Publikationen

The liver is the main organ responsible for the metabolism of ethanol, which suffers significantly as a result of tissue damage due to oxidative stress. It is known that C60 fullerenes are able to efficiently capture and inactivate reactive oxygen species in in vivo and in vitro systems. Therefore, the purpose of this study is to determine whether water-soluble C60 fullerene reduces the level of pathological process development in the liver of rats induced by chronic alcohol intoxication for 3, 6, and 9 months, depending on the daily dose (oral administration; 0.5, 1, and 2 mg/kg) of C60 fullerene throughout the experiment. In this context, the morphology of the C60 fullerene nanoparticles in aqueous solution was studied using atomic force microscopy. Such biochemical parameters of experimental animal blood as ALT (alanine aminotransferase), AST (aspartate aminotransferase), GGT (gamma-glutamyl transferase) and ALP (alkaline phosphatase) enzyme activities, CDT (carbohydrate-deficient transferrin) level, values of pro-antioxidant balance indicators (concentrations of H2O2 (hydrogen peroxide) and GSH (reduced glutathione), activities of CAT (catalase), SOD (superoxide dismutase) and GPx (selenium-dependent glutathione peroxidase)), and pathohistological and morphometric features of liver damage were analyzed. The most significant positive change in the studied biochemical parameters (up to 29 ± 2% relative to the control), as markers of liver damage, was recorded at the combined administration of alcohol (40% ethanol in drinking water) and water-soluble C60 fullerenes in the optimal dose of 1 mg/kg, which was confirmed by small histopathological changes in the liver of rats. The obtained results prove the prospective use of C60 fullerenes as powerful antioxidants for the mitigation of pathological conditions of the liver arising under prolonged alcohol intoxication.

Via inline-nuclear magnetic resonance measurements, the homogeneously catalyzed poly(oxymethylene dimethyl ether) fuel synthesis using trioxane and dimethoxy methane is investigated. Besides the Brønsted acid (BA) catalyst triflic acid (TfOH) different metal halides are studied as Lewis-acidic (LA) catalysts. Among the used LAs, MgCl2, the weakest based on electronegativity, reveals the highest catalytical activity. Additionally, the influence of the concentration of BA and LA is investigated. An increase in BA concentration leads to an exponential increase of the reaction rate, while increasing the concentration of the LA leads to a volcano plot with its optimum at a LA : BA ratio of 1 : 3. The influence of the LA on the electron density of the intermediate formaldehyde is concluded as the main factor for this behavior.

The sensitivity and optical properties of silver nanoprisms (triangular plates with round-truncated corners) are investigated in this paper. Results of boundary element method simulations are compared with experimental results and literature data. Based on electron microscopy images of the synthesized nanoprisms, a single-particle model is set up for simulations with three running parameters: edge length, thickness, and roundness (defined as the radius of the circumscribed circle divided by the edge length). These geometric parameters can be optimized during chemical synthesis to create sensors with improved sensitivity. The effect of biomolecular layers is also investigated. As a novel approach to improve the agreement between the simulated and experimentally measured extinction spectra, the single-particle model is extended to consider the variation of the prisms' parameters in the form of distributions. The resulting extinction cross-section spectra correspond well with the experimental data. The calculated bulk refractive index sensitivity is 670 nm/RIU (RIU stands for refractive index unit) for the single particle model (length = 150 nm, thickness = 10 nm, and roundness = 0.1), while (690 ± 5) nm/RIU for the extended model. The presented model and obtained relations between sensitivity and geometry can be effectively used to design and optimize the fabrication technologies for silver nanoprism-based sensing applications.

The application of a biocompatible polymer nanocarrier can provide target delivery to tumor tissues, improved pharmacokinetics, controlled drug release, etc. Therefore, the proposed strategy was to use the water-soluble star-like copolymers with a Dextran core and Poly(N-isopropylacrylamide) grafts (D-g-PNIPAM) for conjugation with the widely used chemotherapy drugs in oncology-Cisplatin (Cis-Pt) and Doxorubicin (Dox). The molecular characteristics of the copolymer were received using size-exclusion chromatography. The physicochemical characterization of the D-g-PNIPAM-Cis-Pt (or Dox) nanosystem was conducted using dynamic light scattering and FTIR spectroscopy. Using traditional biochemical methods, a comparative analysis of the enhancement of the cytotoxic effect of free Cis-Pt and Dox in combination with D-g-PNIPAM copolymers was performed in cancer cells of the Lewis lung carcinoma line, which are both sensitive and resistant to Dox; in addition, the mechanism of their action in vitro was evaluated.

Six soil samples from three layers of an archaeological investigation profile from a pre-industrial ash deposit place have been investigated by NGS analyses of 16 S rRNA. The three pairs of sample originate from top soil (internal reference), from an intermediate ash layer and from a lower ash layer, formed about two centuries ago. In addition to general abundant bacteria, special genera known as halophilic or alkaline-tolerant have been found as expected from the history of the place and from the measured pH-value and conductivity measurements. The close relations between samples of pairs and the differences between the three soil layers are clearly indicated by abundance correlation and PCA-diagrams. Comparative PCA correlation plots including samples from an archaeological excavation site dedicated to pre-industrial coal mining illustrate the high distinguishability of investigated soils. These relations are particular clearly shown when lower abundant bacteria are regarded. The investigations are a further example for the “ecological memory of soil” reflecting the strong human impact on this pre-industrial embossed place.

A novel nanoformulation, C60 fullerene loaded with a plant alkaloid Piperlongumine (PL) molecules (C60-PL nanocomplex), as a potential drug for the treatment of highly metastatic lung cancer was created and characterized by using ultrasonic technology, computer simulation, atomic force and scanning tunneling microscopy. The aim of the study was to evaluate the antimetastatic potential of PL alone and the C60-PL nanocomplex using Lewis lung carcinoma (LLC) cell line as a model. Evidence has been obtained that the 2:1C60-PL nanocomplex is a potent agent capable of effectively reducing the survival, migration and invasion of LLC cells in vitro, as well as tumor growth and metastasis in vivo compared to free PL. These effects in cell behavior were shown to be associated with an increased Bax expression and high level of cleaved PARP confirming the proapototic potential of C60-PL nanocomplex as well as down-regulation of the mRNA of epithelial-mesenchymal transition regulator Twist1 and cancer stem cell marker CD44, a reduced level of phosphorylated mTOR and adaptor protein Ruk/CIN85. Histological analysis of the lung tissue of LLC-bearing mice showed that in animals that received the C60-PL nanocomplex, the regression of metastases prevailed over their growth. The obtained results allow to conclude that the proposed C60-PL nanocomplex represents a promising drug for the treatment of metastatic lung cancer.

Recent progress in nanotechnology has attracted interest to a biomedical application of the carbon nanoparticle C60 fullerene (C60) due to its unique structure and versatile biological activity. The dual functionality of C60 as a photosensitizer and a drug nanocarrier sets an opportunity to improve the efficiency of chemotherapeutic drugs for cancer cells. Pristine C60 demonstrates time-dependent accumulation with predominant mitochondrial localization in cancer cells. Nanomolar amounts of C60-drug nanocomplexes in 1:1 and 2:1 molar ratios improve the efficiency of cell treatment, complementing it with photodynamic approach. The cooperative enhancement interactions between mechanisms of chemo- and photodynamic therapies contribute to the obtained synergistic effect (namely “1+1>2”). A strong synergy of treatments arising from the combination of C60-mediated drug delivery and C60 photoexcitation indicates that a combination of chemo- and photodynamic treatments with C60-drug nanoformulations could provide a promising synergetic approach for cancer treatment.

In the quest for effective COVID-19 treatments and vaccines, traditional biochemical methods have been paramount, yet the challenge of accommodating diverse viral mutants persists. Recent simulations propose an innovative physical strategy involving an external electric field applied to the SARS-CoV-2 spike protein, demonstrating a reduced viral binding potential. However, limited empirical knowledge exists regarding the characteristics of the spike protein after E-field treatment. Our study addresses this gap by employing diverse analytical techniques to elucidate the impact of low/moderate E-field intensity on the binding of the SARS-CoV-2 spike protein to the ACE2 receptor. Through comprehensive analysis, we unveil a substantial reduction in the spike protein binding capacity validated via enzyme-linked immunosorbent assay and quartz crystal microbalance experiments. Remarkably, the E-field exposure induces significant protein structure rearrangement, leading to an enhanced negative surface zeta potential confirmed by dynamic light scattering. Circular dichroism spectroscopy corroborates these structural changes, showing alterations in the secondary protein structures. This study provides insights into SARS-CoV-2 spike protein modification under an E-field pulse, potentially paving the way for nonbiochemical strategies to mitigate viral reactivity and opening avenues for innovative therapeutic and preventive approaches against COVID-19 and its evolving variants.

Cancer sonodynamic therapy (SDT) is the therapeutic strategy of a high-frequency ultrasound (US) combined with a special sonosensitizer that becomes cytotoxic upon US exposure. The growing number of newly discovered sonosensitizers and custom US in vitro treatment solutions push the SDT field into a need for systemic studies and reproducible in vitro experimental set-ups. In the current research, we aimed to compare two of the most used and suitable SDT in vitro set-ups - “sealed well” and “transducer in well” - in one systematic study. We assessed US pressure, intensity, and temperature distribution in wells under US irradiation. Treatment efficacy was evaluated for both set-ups towards cancer cell lines of different origins, treated with two promising sonosensitizer candidates - carbon nanoparticle C60 fullerene (C60) and herbal alkaloid berberine. C60 was found to exhibit higher sonotoxicity toward cancer cells than berberine. The higher efficacy of sonodynamic treatment with a “transducer in well” set-up than a “sealed well” set-up underlined its promising application for SDT in vitro studies. The “transducer in well” set-up is recommended for in vitro US treatment investigations based on its US-field homogeneity and pronounced cellular effects. Moreover, SDT with C60 and berberine could be exploited as a promising combinative approach for cancer treatment.

The biomechanical parameters of muscle gastrocnemius contraction and biochemical parameters of blood and muscle tissue in rats after chronic alcoholization for 3, 6, and 9 months were studied. The oral administration of C60 fullerene aqueous solution (C60FAS) at doses of 0.5, 1, and 2 mg/kg throughout the experiment was used as a therapeutic agent. C60FAS in each of the experimental groups was administered in three ways: 1 h before alcohol intake, together with alcohol, and 1 h after alcohol intake. The most significant positive effects were recorded when alcohol and C60FAS were administered together at the optimal dose of 1 mg/kg. So, the increase in muscle gastrocnemius contraction force was 20 ± 1%, 33 ± 2% and 65 ± 3% (p < 0.05) compared with control at 3, 6, and 9 months alcoholization, respectively, as well as a high level of its fluctuations correction was observed throughout the experiment. Biochemical parameters such as blood levels of creatinine, creatine phosphokinase, lactate and lactate dehydrogenase as well as pro- and antioxidant balance (content of hydrogen peroxide and reduced glutathione, as well as catalase, selenium-dependent glutathione peroxidase and superoxide dismutase activities) in muscle gastrocnemius tissues decreased from 15 ± 2% (3 months of alcoholization) to 45 ± 2% (9 months of alcoholization) (p < 0.05) compared to controls. The results indicate promising prospects for the use of water-soluble C60 fullerenes, as powerful antioxidants, for the correction of pathological conditions of the muscular system arising from alcohol intoxication.

Background: Being a scavenger of free radicals, C60 fullerenes can influence on the physiological processes in skeletal muscles, however, the effect of such carbon nanoparticles on muscle contractility under acute muscle inflammation remains unclear. Thus, the aim of the study was to reveal the effect of the C60 fullerene aqueous solution (C60FAS) on the muscle contractile properties under acute inflammatory pain. Methods: To induce inflammation a 2.5% formalin solution was injected into the rat triceps surae (TS) muscle. High-frequency electrical stimulation has been used to induce tetanic muscle contraction. A linear motor under servo-control with embedded semi-conductor strain gauge resistors was used to measure the muscle tension. Results: In response to formalin administration, the strength of TS muscle contractions in untreated animals was recorded at 23% of control values, whereas the muscle tension in the C60FAS-treated rats reached 48%. Thus, the treated muscle could generate 2-fold more muscle strength than the muscle in untreated rats. Conclusions: The attenuation of muscle contraction force reduction caused by preliminary injection of C60FAS is presumably associated with a decrease in the concentration of free radicals in the inflamed muscle tissue, which leads to a decrease in the intensity of nociceptive information transmission from the inflamed muscle to the CNS and thereby promotes the improvement of the functional state of the skeletal muscle.

The energies of the frontier molecular orbitals determine the optoelectronic properties in organic films, which are crucial for their application, and strongly depend on the morphology and supramolecular structure. The impact of the latter two properties on the electronic energy levels relies primarily on nearest-neighbor interactions, which are difficult to study due to their nanoscale nature and heterogeneity. Here, an automated method is presented for fabricating thin films with a tailored ratio of surface to bulk sites and a controlled extension of domain edges, both of which are used to control nearest-neighbor interactions. This method uses a Langmuir–Schaefer-type rolling transfer of Langmuir layers (rtLL) to minimize flow during the deposition of rigid Langmuir layers composed of π-conjugated molecules. Using UV–vis absorption spectroscopy, atomic force microscopy, and transmission electron microscopy, it is shown that the rtLL method advances the deposition of multi-Langmuir layers and enables the production of films with defined morphology. The variation in nearest-neighbor interactions is thus achieved and the resulting systematically tuned lowest unoccupied molecular orbital (LUMO) energies (determined via square-wave voltammetry) enable the establishment of a model that functionally relates the LUMO energies to a morphological descriptor, allowing for the prediction of the range of accessible LUMO energies.

Soil samples taken during archaeological investigations of a historical tannery area in the eastern suburb of the medieval city of Jena have been investigated by 16S r-RNA gene profiling. The analyses supplied a large spectrum of interesting bacteria, among them Patescibacteria, Methylomirabilota, Asgardarchaeota, Zixibacteria, Sideroxydans and Sulfurifustis. Samples taken from soil inside the residues of large vats show large differences in comparison to the environmental soil. The PCAs for different abundance classes clearly reflect the higher similarity between the bacterial communities of the outside-vat soils in comparison with three of the inside-vat soil communities. Two of the in-side vat soils are distinguishable from the other samples by separate use of each abundance class, but classes of lower abundance are better applicable than the highly abundant bacteria for distinguishing the sampling sites by PCA, in general. This effect could be interpreted by the assumption that less abundant types in the 16S r-RNA data tend to be more related to an earlier state of soil development than the more abundant and might be, therefore, better suited for conclusions on the state of the soils in an earlier local situation. In addition, the analyses allowed identification of specific features of each single sampling site. In one site specifically, DNA hints of animal residue-related bacteria were found. Obviously, the special situation in the in-site vat soils contributes to the diversity of the place, and enhances its Beta-diversity. Very high abundancies of several ammonia-metabolizing and of sulphur compound-oxidizing genera in the metagenomics data can be interpreted as an echo of the former tannery activities using urine and processing keratin-rich animal materials. In summary, it can be concluded that the 16S r-RNA analysis of such archaeological places can supply a lot of data related to ancient human impacts, representing a kind of “ecological memory of soil”.

Cholesterin hat es bis in den Alltagssprachgebrauch gebracht. Allein deshalb ist es für Praktika im Chemiestudium ein interessanter Vertreter der Steroide. Zudem ist es einfach zu gewinnen.

Multi-walled carbon nanotubes doped with sulfur and nitrogen (S-N-MWCNTs) were grown onto silicon/silicon oxide wafer by means of chemical vapor deposition upon decomposition of dimethyl sulfoxide (DMSO) and acetonitrile (ACN) in presence of catalyst. The S-N-MWCNTs were characterized by scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The findings demonstrate that S-N-MWCNTs exhibit bamboo-shaped nanostructure, quite similar to pure nitrogen-doped carbon nanotubes. The S-N-MWCNTs were investigated with respect to their electrochemical response to ferrocyanide/ferricyanide, [Fe(CN)6]4-/3- in potassium chloride aqueous solutions by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The recorded CVs demonstrate strong dependence of electrochemical response, electron transfer kinetics, and sensitivity of S-N-MWCNTs on concentration of decomposed DMSO precursor. Namely, upon increasing concentration of decayed DMSO up to 2% wt. the current density, the electron transfer kinetics, and the sensitivity of S-N-MWCNTs toward [Fe(CN)6]4-/3- tend to enhance. The extracted EIS results approve that when DMSO reaches the optimum concentration of 2% wt. the barrier for electron transfer decreases significantly leading, consequently, to faster electron transfer kinetics. The S-N-MWCNTs exhibit considerable stability and excellent reproducibility, and thus it can be considered suitable analytical tool for detection of redox systems at micromolar level.

Cathode-associated microbial communities (caMCs) are the functional key elements in the conversion of excess electrical energy into biomass. In this study, we investigated the development of electrochemical caMCs based on two-chamber microbial electrolytic cells (MECs) after optimization of media composition. Microbial communities obtained from a historical soil sample were inoculated into the cathode chamber of MECs. The inorganic medium with (A) carbon dioxide in air or (B) 100 mM sodium bicarbonate as carbon source was used in the absence of any organic carbon source. After 12 days of operation, the experimental results showed that (1) the bacterial community in group B exhibited lush growth and (2) a single strain TX168 Epilithonimonas bovis isolated from group A indicated electrochemical activity and synthesized large volumes of biomass using sodium bicarbonate. We also analyzed the caMCs of the MECs and reference samples without electro-cultivation using 16S rRNA gene sequencing. The results showed that the caMCs of MECs in groups A and B were dominated by the genera Acinetobacter and Pseudomonas. The caMCs were further inoculated and cultured on different agars to isolate specific electroactive bacterial strains. Overall, our study highlights the possibility of converting excess energy into biomass by electro-cultivation and the importance of selecting appropriate media to enrich specific microbial communities and single strains in MECs.

This study presents the development of a hierarchical design concept for the synthesis of multi-scale polymer particles with up to five levels of organization. The synthesis of core-shell microparticles containing nested sets of dispersed metal and polymer micro- and nanoparticles is achieved through in situ photopolymerization using a double co-axial capillaries microfluidic device. The flow rates of the carrier, shell, and core phases are optimized to control particle size and result in stable core-shell particles with well-dispersed three-level composites in the shell matrix. The robustness and reversibility of these core-shell particles are demonstrated through five cycles of drying and re-swelling, showing that the size and structure of core-shell particles remain unchanged. Additionally, the permeability and mobility of dye molecules within the shell matrix are tested and showed that different molecular weight dyes have different penetration times. This study highlights the potential of microfluidics as a powerful tool for the controlled and precise synthesis of complex structured materials and demonstrates the versatility and potential of these core-shell particles for sensing applications as particle-based surface-enhanced Raman scattering (SERS).

Graphene oxide (GO) derived from the oxidization of graphite exhibits high specific surface area with potential in electrochemical applications. Furthermore, silver and zinc oxide nanoparticles, further denoted as AgNPs and ZnONPs, respectively, display superior physicochemical and electronic properties, that would significantly improve the electrocatalytic properties by being applied in electrochemical sensing. Consequently, in the present work, three different hybrid nanomaterials consisting of reduced graphene oxide (rGO) modified with either AgNPs, ZnONPs, or combined AgZnONPs were synthesized and characterized. The synthesis of GO was performed by a modified Hummer's method, while the decoration of GO with the nanoparticles was carried out by self-assembly solvothermal processes. The Ag-rGO, ZnO-rGO, and AgZnO-rGO nanocomposite hybrid materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDX). Furthermore, the electrochemical responses of the fabricated nanocomposites towards the standard ferrocyanide/ferricyanide [Fe(CN)6]3-/4- redox system were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The results have been explained in terms of structural differences between the nanoparticles formed on the surface of the fabricated nanocomposite materials. Namely, the improved electrochemical performance of ZnO-rGO can be attributed to the high surface to volume ratio of ZnO, which provides greater area of electrode/electrolyte junction and consequently, large number of sites at the electrolyte-ZnO interface. The aim of the present work is the fabrication of novel high-performance rGO-based nanomaterials for applications in electrochemical sensing.

The carbon fullerene C60 is an anti-inflammatory substance that reduces cellular stress levels. In this study, C60 fullerenes were deposited on complex dental implants to improve cell attachment and vitality. For the first time, fullerene C60 films were deposited via high-vacuum sublimation on complex-shaped Ti-6Al-4V dental implants with a threaded-screw design. The “as-deposited” fullerene C60 films were compared with fullerene C60 films on dental Ti-6Al-4V implants using a threaded-screw design after three weeks of incubation in Hank's balanced salt solution (HBSS). It was proven by Raman spectroscopy that the incubation in potassium and alkali-ion rich HBSS at 37 &ring;C resulted in a reduction of monomeric fullerene C60 fraction and an increase in dimer, linear chain and polymerized C60 molecules. Furthermore, the structure of the C60 films differed depending on the measurement position on dental implants with a threaded-screw design. The fraction of monomeric fullerene C60 was highest on top of the trapezoidal thread, which had a micropatterned topography. Nano-indentations were performed at this position with a maximum load of 1000 μN. The fullerene C60 films showed a nano-hardness of 0.3 ± 0.1 GPa and a Young's modulus of 7.6 ± 3.6 GPa at this position, which is typical for monomeric fullerene C60 with weak interatomic interaction in the face-centred-cubic crystal structure. The murine embryonal calvarial stem-cell line MC3T3-E1 (ECACC, UK), which is driven toward osteogenic differentiation, spread out extremely well on the fullerene C60 film, with improved cell morphology compared to uncoated Ti-6Al-4V. Cell nuclei density were determined to be 237.5 cell nuclei per mm2 for the Ti-6Al-4V dental implants with a threaded-screw design with fullerene C60 coating in “as-deposited” condition. This was approximately 40 % better than that of uncoated Ti-6Al-4V dental implants with a threaded-screw design.

The acoustic pressure waves of ultrasound (US) not only penetrate biological tissues deeper than light, but they also generate light emission, termed sonoluminescence. This promoted the idea of its use as an alternative energy source for photosensitizer excitation. Pristine C60 fullerene (C60), an excellent photosensitizer, was explored in the frame of cancer sonodynamic therapy (SDT). For that purpose, we analyzed C60 effects on human cervix carcinoma HeLa cells in combination with a low-intensity US treatment. The time-dependent accumulation of C60 in HeLa cells reached its maximum at 24 h (800 ± 66 ng/106 cells). Half of extranuclear C60 is localized within mitochondria. The efficiency of the C60 nanostructure’s sonoexcitation with 1 MHz US was tested with cell-based assays. A significant proapoptotic sonotoxic effect of C60 was found for HeLa cells. C60′s ability to induce apoptosis of carcinoma cells after sonoexcitation with US provides a promising novel approach for cancer treatment.

Photodynamic Therapy (PDT) is a non-invasive therapeutic modality that can treat a wide variety of cancer types by means of photosensitizer drug, light, and oxygen. Due to enhanced specificity and fewer side effects, PDT can be an alternative approach for cancer treatments. However, conventional photosensitizers (PSs) exhibit low selectivity, hydrophobicity, and limited photophysical properties. Nanotechnology emerges as a potential solution to these issues and improves PDT efficiency. Nanomaterials such as Carbon Quantum Dots (CQDs) and Graphene Quantum Dots (GrQDs) have been widely applied on PDT research recently, regarding their excellent photoluminescence properties, biocompatibility, as well as their hydrophilicity. The present review article summarizes the main features of PDT and carbon-based quantum dots with an emphasis on used PSs and methods for synthesis of carbon dots. Additionally, the most recent applications of CQDs and GrQDs in PDT have been extensively discussed. The main conclusion that arises is that carbon-based quantum dots seem to be a powerful tool in cancer diagnosis and treatment.

Platelets are cell fragments from megakaryocytes devoid of the cell nucleus. They are highly sensitive and easily activated by nonphysiological surfaces. Activated platelets have an intrinsic mechanism to release various proteins that participate in multiple pathways, initiating the platelet activation cascade. Surface-induced platelet activation is a challenge encountered during platelet storage, which eventually leads to aggregation of platelets and can thereby result in the degradation of the platelet concentrates. We have previously reported that surface-induced platelet activation can be minimized by either modifying their contact surfaces with polymers or introducing nanogroove patterns underneath the platelets. Here, we investigated the response of platelets to various nanotopographical surfaces printed using fluidic force microscopy (FluidFM). We found that the hemispherical array (grid) and hexagonal tile (hive) structures caused a reduction of surface stiffness, which leads to an inhibition of platelet adhesion. Our results reveal that nanopatterns enable the inhibition of platelet activation on surfaces, thus implying that development in nanotexturing of storage bags can extend the lifetime of platelet concentrates.

Heparin-induced thrombocytopenia (HIT) is caused by newly formed platelet-activating antibodies against complexes formed between platelet factor 4 (PF4) and heparin (H). HIT can result in life-threatening complications; thus, early detection of HIT antibodies is crucial for the treatment of the disease. The enzyme-linked immune absorbance assay (ELISA) for the identification of HIT antibodies is widely used in many laboratories, but in general, this test provides only ∼50% accuracy while other methods show multiple limitations. Here, we developed a new cell-based ELISA to improve the detection of HIT antibodies. Instead of immobilizing PF4 or PF4/H complexes directly onto a plate as in the standard ELISA, we added the complexes on breast cancer cells, i.e., cell line MDA-MB-231, and applied the same protocol for antibody detection. Using confocal laser scanning microscopy and flow cytometry for the characterization of bound complexes, we identified two types of HIT-mimicked antibodies (KKO and 1E12), which were able to differentiate from the non-HIT antibody (RTO). PF4-treated MDA-MB-231 cells allowed binding of HIT-mimicked antibodies better than PF4/H complexes. With human sera, the cell-based ELISA allowed better differentiation of clinically relevant from non-clinically relevant HIT antibodies as compared with the standard ELISA. Our findings provide a potential approach that contributes to the development of better assays for the detection of HIT antibodies.

Three-dimensional printing at the micro-/nanoscale represents a new challenge in research and development to achieve direct printing down to nanometre-sized objects. Here, FluidFM, a combination of microfluidics with atomic force microscopy, offers attractive options to fabricate hierarchical polymer structures at different scales. However, little is known about the effect of the substrate on the printed structures and the integration of (bio)functional groups into the polymer inks. In this study, we printed micro-/nanostructures on surfaces with different wetting properties, and integrated molecules with different functional groups (rhodamine as a fluorescent label and biotin as a binding tag for proteins) into the base polymer ink. The substrate wetting properties strongly affected the printing results, in that the lateral feature sizes increased with increasing substrate hydrophilicity. Overall, ink modification only caused minor changes in the stiffness of the printed structures. This shows the generality of the approach, as significant changes in the mechanical properties on chemical functionalization could be confounders in bioapplications. The retained functionality of the obtained structures after UV curing was demonstrated by selective binding of streptavidin to the printed structures. The ability to incorporate binding tags to achieve specific interactions between relevant proteins and the fabricated micro-/nanostructures, without compromising the mechanical properties, paves a way for numerous bio and sensing applications. Additional flexibility is obtained by tuning the substrate properties for feature size control, and the option to obtain functionalized printed structures without post-processing procedures will contribute to the development of 3D printing for biological applications, using FluidFM and similar dispensing techniques.

Die Aufklärung von Reaktionsmechanismen ist in der Katalyse wichtig, um die geschwindigkeitsbegrenzende Schritte zu verstehen und zu beschleunigen. Mit maschinellem Lernen lassen dann sich auf Basis der Mechanismen neue Katalysatoren entwickeln. Photochemische Umsetzungen in weichen Membranen folgen einer anderen Kinetik als Reaktionen in Lösung. Mikroschwimmer, Mikromotoren oder Phototaxis zählen zu aktiver Materie. Sie wandeln kontinuierlich Energie aus ihrer Umgebung um und bewegen sich autonom.

Heparin-induced thrombocytopenia (HIT), a severe autoimmune disorder, occurs in patients undergoing heparin therapy. The presence of platelet-activating antibodies against platelet factor 4/Heparin in the blood confirms patients suffering from HIT. The most widely used methods for HIT diagnosis are immunoassays but the results only suit to rule out HIT as the assays provide only around 50% specificity. To confirm HIT, samples with positive results in immunoassays are retested in functional assays (>98% specificity) that track platelet-activating antibodies via platelet aggregation. However, the protocols in functional assays are either time-consuming (due to the requirement of the detection of serotonin release) or require highly trained staff for the visualization of platelets. Here, we applied a cheap and easy-to-use contactless sensor, which employs high-frequency microwaves to detect the changes in the resonant frequency caused by platelet aggregation/activation. Analysis of change in conductivity and permittivity allowed us to distinguish between HIT-like (KKO) and non-HIT-like (RTO) antibodies. KKO caused a stronger reduction of conductivity of platelet samples than RTO. Our results imply that the high-frequency contactless sensor can be a promising approach for the development of a better and easier method for the detection of HIT.

This work presents the application of droplet-based microfluidics for the cultivation of microspores from Brassica napus using the doubled haploid technology. Under stress conditions (e.g. heat shock) or by chemical induction a certain fraction of the microspores can be reprogrammed and androgenesis can be induced. This process is an important approach for plant breeding because desired plant properties can be anchored in the germline on a genetic level. However, the reprogramming rate of the microspores is generally very low, increasing it by specific stimulation is, therefore, both a necessary and challenging task. In order to accelerate the optimisation and development process, the application of droplet-based microfluidics can be a promising tool. Here, we used a tube-based microfluidic system for the generation and cultivation of microspores inside nL-droplets. Different factors like cell density, tube material and heat shock conditions were investigated to improve the yield of vital plant organoids. Evaluation and analysis of the stimuli response were done on an image base aided by an artificial intelligence cell detection algorithm. Droplet-based microfluidics allowed us to apply large concentration programs in small test volumes and to screen the best conditions for reprogramming cells by the histone deacetylase inhibitor trichostatin A and for enhancing the yield of vital microspores in droplets. An enhanced reprogramming rate was found under the heat shock conditions at 32 &ring;C for about 3 to 6 days. In addition, the comparative experiment with MTP showed that droplet cultivation with lower cell density (<10 cells per droplet) or adding media after 3 or 6 days significantly positively affects the microspore growth and embryo rate inside 120 nL droplets. Finally, the developed embryos could be removed from the droplets and further grown into mature plants. Overall, we demonstrated that the droplet-based tube system is suitable for implementation in an automated, miniaturized system to achieve the induction of embryogenic development in haploid microspore stem cells of Brassica napus.

The C-H activation and subsequent carbonylation mediated by metal complexes, i. e., Rh(I) complexes, has drawn considerable attention in the past. To extend the mechanistic insight from Rh complexes featuring monodentate ligands like P(Me)3 towards more active bisphosphines (PLP), a computationally derived fully conclusive mechanistic picture of the Rh(I)-catalyzed C-H activation and carbonylation is presented here. Depending on the nature of the bisphosphine ligand, the highest lying transition state (TS) is associated either to the initial C-H activation in [Rh(PLP)(CO)(Cl)] or to the rearrangement of the chloride in [Rh(PLP)(H)(R)(Cl)]. The chloride rearrangement was found to play a key role in the subsequent carbonylation. A set of 20 complexes of different architectures was studied, in order to fine tune the C-H activation in a knowledge-driven approach. The computational analysis suggests that a flexible ligand architecture with aromatic rings can potentially increase the performance of Rh-based catalysts for the C-H activation.

The principle of droplet-based microfluidics was used for the characterization of dose/response functions of the soil bacteria Rhodococcus sp. and Chromobacterium vaccinii using a combination of optical and electrical sensors for the detection of bacterial growth and metabolic activity. For electrical characterization, a micro flow-through impedance module was developed which assessed the response of bacterial populations inside 500 nL fluid segments without direct galvanic contact between the electrodes and the electrolyte. It was found that the impedance sensor can detect an increase in cell density and is particularly suited for monitoring the metabolic response due to changes in the cultivation medium inside the separated fluid segments. Due to this sensitivity, the sensor is useful for investigating growing bacteria or cell cultures in small fluid compartments and obtaining highly resolved dose-response functions by microfluid segment sequences. The impedimetric data agree well with the optical data concerning the characteristic response of bacteria populations in the different concentration regions of heavy metal ions. However, the sensor supplies valuable complementary data on metabolic activity in case of low or negligible cell division rates.

This metagenomics investigation of three closely adjacent sampling sites from an archaeological excavation of a pre-industrial coal mining exploration shaft provides detailed information on the composition of the local soil bacterial communities. The observed significant differences between the samples, reflected in the 16S r-RNA analyses, were consistent with the archaeologically observed situation distinguishing the coal seam, the rapidly deposited bright sediment inside an exploration shaft, and the topsoil sediment. In general, the soils were characterized by a dominance of Proteobacteria, Actinobacteria, Acidobacteria, and Archaea, whereas the coal seam was characterized by the highest proportion of Proteobacteria; the topsoil was characterized by very high proportions of Archaea - in particular, Nitrosotaleaceae - and Acidobacteria, mainly of Subgroup 2. Interestingly, the samples of the fast-deposited bright sediment showed a rank function of OTU abundances with disproportional values in the lower abundance range. This could be interpreted as a reflection of the rapid redeposition of soil material during the refilling of the exploration shaft in the composition of the soil bacterial community. This interpretation is supported by the observation of a comparatively high proportion of reads relating to bacteria known to be alkaliphilic in this soil material. In summary, these investigations confirm that metagenomic analyses of soil material from archaeological excavations can provide valuable information about the local soil bacterial communities and the historical human impacts on them.

Hierarchical assemblies of functional polymer particles are promising due to their surface as well as physicochemical properties. However, hierarchical composites are complex and challenging to form due to the many steps necessary for integrating different components into one system. Highly structured four-level composite particles were formed in a four-step process. First of all, gold (Au) nanoparticles, poly(methyl methacrylate) (PMMA) nanoparticles, and poly(tripropylene glycol diacrylate) (poly-TPGDA) microparticles were individually synthesized. By applying microfluidic techniques, polymer nano- and microparticles were formed with tunable size and surface properties. Afterwards, the negatively charged gold nanoparticles and PMMA particles functionalized with a positively charged surface were mixed to form Au/PMMA assemblies. The Au/PMMA composites were mixed and incubated with poly-TPGDA microparticles to form ternary Au/PMMA/poly-TPGDA assemblies. For the formation of composite-containing microparticles, Au/PMMA/poly-TPGDA composites were dispersed in an aqueous acrylamide-methylenebisacrylamide solution. Monomer droplets were formed in a co-flow microfluidic device and photopolymerized by UV light. In this way, hierarchically structured four-level composites consisting of four different size ranges - 0.025/0.8/30/1000 μm - were obtained. By functionalizing polymer nano- and microparticles with different fluorescent dyes, it was possible to visualize the same composite particle under two different excitation modes (λex = 395-440 and λex = 510-560 nm). The Au/PMMA/poly-TPGDA composite-embedded polyacrylamide microparticles can be potentially used as a model for the creation of composite particles for sensing, catalysis, multilabeling, and biomedical applications.

Droplet-based microfluidic screening techniques can benefit from interfacing established microtiter plate-based screening and sample management workflows. Interfacing tools are required both for loading preconfigured microtiter-plate (MTP)-based sample collections into droplets and for dispensing the used droplets samples back into MTPs for subsequent storage or further processing. Here, we present a collection of Digital Microfluidic Pipetting Tips (DMPTs) with integrated facilities for droplet generation and manipulation together with a robotic system for its operation. This combination serves as a bidirectional sampling interface for sample transfer from wells into droplets (w2d) and vice versa droplets into wells (d2w). The DMPT were designed to fit into 96-deep-well MTPs and prepared from glass by means of microsystems technology. The aspirated samples are converted into the channel-confined droplets’ sequences separated by an immiscible carrier medium. To comply with the demands of dose-response assays, up to three additional assay compound solutions can be added to the sample droplets. To enable different procedural assay protocols, four different DMPT variants were made. In this way, droplet series with gradually changing composition can be generated for, e.g., 2D screening purposes. The developed DMPT and their common fluidic connector are described here. To handle the opposite transfer d2w, a robotic transfer system was set up and is described briefly.

Aqueous-organic redox flow batteries (RFBs) have gained considerable interest in recent years, given their potential for an economically viable energy storage at large scale. This, however, strongly depends on both the robustness of the underlying electrolyte chemistry against molecular decomposition reactions as well as the device's operation. With regard to this, the presented study focuses on the use of in situ IR spectroscopy in combination with a multivariate curve resolution approach to gain insight into both the molecular structures of the active materials present within the electrolyte as well as crucial electrolyte state parameters, represented by the electrolyte's state of charge (SOC) and state of health (SOH). To demonstrate the general applicability of the approach, methyl viologen (MV) and bis(3-trimethylammonium)propyl viologen (BTMAPV) are chosen, as viologens are frequently used as negolytes in aqueous-organic RFBs. The study's findings highlight the impact of in situ spectroscopy and spectral deconvolution tools on the precision of the obtainable SOC and SOH values. Furthermore, the study indicates the occurrence of multiple viologen dimers, which possibly influence the electrolyte lifetime and charging characteristics.

The development of an effective therapy aimed at restoring muscle dysfunctions in clinical and sports medicine, as well as optimizing working activity in general remains an urgent task today. Modern nanobiotechnologies are able to solve many clinical and social health problems, in particular, they offer new therapeutic approaches using biocompatible and bioavailable nanostructures with specific bioactivity. Therefore, the nanosized carbon molecule, C60 fullerene, as a powerful antioxidant, is very attractive. In this study, a comparative analysis of the dynamic of muscle soleus fatigue processes in rats was conducted using 50 Hz stimulation for 5 s with three consistent pools after intraperitoneal administration of the following antioxidants: C60 fullerene (a daily dose of 1 mg/kg one hour prior to the start of the experiment) and N-acetylcysteine (NAC; a daily dose of 150 mg/kg one hour prior to the start of the experiment) during five days. Changes in the integrated power of muscle contraction, levels of the maximum and minimum contraction force generation, time of reduction of the contraction force by 50% of its maximum value, achievement of the maximum force response, and delay of the beginning of a single contraction force response were analyzed as biomechanical markers of fatigue processes. Levels of creatinine, creatine phosphokinase, lactate, and lactate dehydrogenase, as well as pro- and antioxidant balance (thiobarbituric acid reactive substances, hydrogen peroxide, reduced glutathione, and catalase activity) in the blood of rats were analyzed as biochemical markers of fatigue processes. The obtained data indicate that applied therapeutic drugs have the most significant effects on the 2nd and especially the 3rd stimulation pools. Thus, the application of C60 fullerene has a (50-80)% stronger effect on the resumption of muscle biomechanics after the beginning of fatigue than NAC on the first day of the experiment. There is a clear trend toward a positive change in all studied biochemical parameters by about (12-15)% after therapeutic administration of NAC and by (20-25)% after using C60 fullerene throughout the experiment. These findings demonstrate the promise of using C60 fullerenes as potential therapeutic nanoagents that can reduce or adjust the pathological conditions of the muscular system that occur during fatigue processes in skeletal muscles.

Recent trends in 3D cell culturing has placed organotypic tissue models at another level. Now, not only is the microenvironment at the cynosure of this research, but rather, microscopic geometrical parameters are also decisive for mimicking a tissue model. Over the years, technologies such as micromachining, 3D printing, and hydrogels are making the foundation of this field. However, mimicking the topography of a particular tissue-relevant substrate can be achieved relatively simply with so-called template or morphology transfer techniques. Over the last 15 years, in one such research venture, we have been investigating a micro thermoforming technique as a facile tool for generating bioinspired topographies. We call them MatriGrid®s. In this research account, we summarize our learning outcome from this technique in terms of the influence of 3D micro morphologies on different cell cultures that we have tested in our laboratory. An integral part of this research is the evolution of unavoidable aspects such as possible label-free sensing and fluidic automatization. The development in the research field is also documented in this account.

Supramolecular materials provide unique opportunities to mimic both the structure and mechanics of the biopolymer networks that compose the extracellular matrix. However, strategies to modify their filamentous structures in space and time in 3D cell culture to study cell behavior as encountered in development and disease are lacking. We herein disclose a multicomponent squaramide-based supramolecular material whose mechanics and bioactivity can be controlled by light through co-assembly of a 1,2-dithiolane (DT) monomer that forms disulfide cross-links. Remarkably, increases in storage modulus from ∼200 Pa to >10 kPa after stepwise photo-cross-linking can be realized without an initiator while retaining colorlessness and clarity. Moreover, viscoelasticity and plasticity of the supramolecular networks decrease upon photo-irradiation, reducing cellular protrusion formation and motility when performed at the onset of cell culture. When applied during 3D cell culture, force-mediated manipulation is impeded and cells move primarily along earlier formed channels in the materials. Additionally, we show photopatterning of peptide cues in 3D using either a photomask or direct laser writing. We demonstrate that these squaramide-based filamentous materials can be applied to the development of synthetic and biomimetic 3D in vitro cell and disease models, where their secondary cross-linking enables mechanical heterogeneity and shaping at multiple length scales.

Functional biomechanical parameters of muscle soleus contraction in rats as well as selected blood biochemical parameters were studied during the first 3 days of post-traumatic syndrome progression caused by the destruction of muscle cells by compression. Single administration of the antioxidant C60 fullerene and the selective agonist of TRPM8 channels menthol were used as therapeutic agents. Injection of C60 fullerene at a concentration of 1 mg/kg into the damaged muscle improved its contractile function by 25-28%. The use of combined injections of C60 fullerene and menthol (at the concentration 1 mg/kg) improved this index by additional 27-39% and simultaneously stabilized the decrease in muscle strength observed throughout the experiment. A tendency towards a decrease in the indexes of the above described biochemical parameters by 10-15% were found with the therapeutic administration of C60 fullerene. With combined injections of C60 fullerene and menthol, the above described biochemical parameters decreased by an additional 17-24%. The synergism between the action of menthol and C60 fullerene on the post-traumatic recovery of skeletal muscle function opens up new perspectives for the clinical application of this combination therapy.

Biomechanical and biochemical changes in the muscle soleus of rats during imitation of hind limbs unuse were studied in the model of the Achilles tendon rupture (Achillotenotomy). Oral administration of water-soluble C60 fullerene at a dose of 1 mg/kg was used as a therapeutic agent throughout the experiment. Changes in the force of contraction and the integrated power of the muscle, the time to reach the maximum force response, the mechanics of fatigue processes development, in particular, the transition from dentate to smooth tetanus, as well as the levels of pro- and antioxidant balance in the blood of rats on days 15, 30 and 45 after injury were described. The obtained results indicate a promising prospect for C60 fullerene use as a powerful antioxidant for reducing and correcting pathological conditions of the muscular system arising from skeletal muscle atrophy.

The personal risks of infection, as well as the conditions for achieving herd immunity, are strongly dependent on an individual’s response to the infective agents on the one hand, and the individual’s reactions to vaccination on the other hand. The main goal of this work is to illustrate the importance of quantitative individual effects for disease risk in a simple way. The applied model was able to illustrate the quantitative effects, in the cases of different individual reactions, after exposition to viruses or bacteria and vaccines. The model was based on simple kinetic equations for stimulation of antibody production using different concentrations of the infective agent, vaccine and antibodies. It gave a qualitative explanation for the individual differences in breakthrough risks and different requirements concerning a second, third or further vaccinations, reconsidering different efficiencies of the stimulation of an immune reaction.

Noncovalent water-soluble nanocomplexes of C60 fullerene (C60) with chemotherapeutic drugs (Doxorubicin (Dox), Cisplatin (Cis), and herbal alkaloid Berberine (Ber)) were created. Their anticancer action toward various tumor cells was studied in vitro, addressing specifically their biological synergy, compared with the action of these drugs in the non-immobilized form. Different theoretical and experimental (SEM and AFM microscopy, UV-Vis, DLS, NMR and SANS spectroscopy, ITC calorimetry) methods were applied for getting insight into the nature of the nanocomplexes with drug molecules, as well as into the physical forces enabling stabilization of these complexes. Physicochemical mechanisms were proposed for drug interaction with C60. An enhancement of the toxic action of the created water-soluble C60-drug nanocomplexes toward cancer cells, compared to the action of free drug, was found. Specifically, the C60-Dox nanocomplexes demonstrated ˜3.5 higher cytotoxic potential in the leukemic cell lines (CCRF-CEM, Jurkat, THP1, and Molt-16) in comparison with free Dox in the nanometer range of concentrations. Besides, C60 doubled the intracellular level of the up-taken Dox, which also evidenced its function as a nanocarrier. The toxic effect of C60-Cis nanocomplex toward Lewis lung carcinoma (LLC) cells was shown to be higher with IC50 values 3.3 and 4.5 times at 48 h and 72 h, respectively, as compared to the IC50 of free drug. 12.5 [my] Cis had no effect on LLC cells' viability. The C60-Cis nanocomplex in Cis-equivalent concentration substantially decreased the viability of tumor cells, impaired their shape and adhesion, inhibited migration, and induced their accumulation in the pro-apoptotic sub-G1 phase of cell cycle. An induction of apoptosis by the C60-Cis nanocomplex was confirmed by the activation of caspase 3/7 and externalization of phosphatidylserine on the outer membrane of LLC cells after their double staining with the Annexin V-FITC/PI. The complexation with C60 promoted intracellular uptake of the Ber. An increase in C60 concentration in the C60-Ber nanocomplexes was accompanied by the elevation of their antiproliferative potential toward CCRF-CEM cells in the order: free Ber < 1:2 < 1:1 < 2:1.These findings suggest a universal potential of water-soluble pristine C60 as a unique nano-platform for the delivery of the chemotherapeutic drugs in cytotoxic effect of these drugs.

Introduction: The emergence of a new member of the Coronaviridae family, which caused the 2020 pandemic, requires detailed research on the evolution of coronaviruses, their structure and properties, and interaction with cells. Modern nanobiotechnologies can address the many clinical challenges posed by the COVID-19 pandemic. In particular, they offer new therapeutic approaches using biocompatible nanostructures with “specific” antiviral activity. Therefore, the nanosized spherical-like molecule (0.72 nm in diameter) composed of 60 carbon atoms, C60 fullerene, is of interest in terms of fighting coronaviruses due to its high biological activity. In here, we aim to evaluate the effectiveness of anticoronavirus action of water-soluble pristine C60 fullerene in the model and in vitro systems. As a model, apathogenic for human coronavirus, we used transmissible gastroenteritis virus of swine (TGEV), which we adapted to the BHK-21 cell culture (kidney cells of a newborn Syrian hamster).Methods: The shape and size of the particles present in C60 fullerene aqueous colloidal solution (C60FAS) of given concentration, as well as C60FAS stability (value of zeta potential) were studied using microscopic (STM, scanning tunneling microscopy, and AFM, atomic force microscopy) and spectroscopic (DLS, dynamic light scattering) methods. The cytopathic effect of TGEV was determined with the help of a Leica DM 750 microscope and the degree of monolayer changes in cells was assessed. The microscopy of the viral suspension was performed using a high resolution transmission electron microscope (HRTEM; JEM-1230, Japan). Finally, the search for and design of optimal possible complexes between C60 fullerene and target proteins in the structure of SARS-CoV-2 coronavirus, evaluation of their stability in the simulated cellular environment were performed using molecular dynamics and docking methods.Results: It was found that the maximum allowable cytotoxic concentration of C60 fullerene is 37.5 ± 3.0 [my]g/ml. The investigated C60FAS reduces the titer of coronavirus infectious activity by the value of 2.00 ± 0.08 TCID50/ml. It was shown that C60 fullerene interacts directly with SARS-CoV-2 proteins, such as RdRp (RNA-dependent RNA polymerase) and 3CLpro (3-chymotrypsin-like protease), which is critical for the life cycle of the coronavirus and, thus, inhibits its functional activity. In both cases, C60 fullerene fills the binding pocket and gets stuck there through stacking and steric interactions.Conclusion: Pioneer in vitro study to identify the anticoronavirus activity of water-soluble pristine C60 fullerenes indicates that they are highly promising for further preclinical studies, since a significant inhibition of the infectious activity of swine coronavirus of transmissible gastroenteritis in BHK-21 cell culture was found. According to molecular modeling results, it was shown that C60 fullerene can create the stable complexes with 3CLpro and RdRp proteins of SARS-CoV-2 coronavirus and, thus, suppress its functional activity.

In this study the catalytic activity of different gold and bimetallic nanoparticle solutions towards the reduction of methylene blue by sodium borohydride as a model reaction is investigated. By utilizing differently shaped gold nanoparticles, i.e., spheres, cubes, prisms and rods as well as bimetallic gold–palladium and gold-platinum core-shell nanorods, we evaluate the effect of the catalyst surface area as available gold surface area, the shape of the nanoparticles and the impact of added secondary metals in case of bimetallic nanorods. We track the reaction by UV/Vis measurements in the range of 190-850 nm every 60 s. It is assumed that the gold nanoparticles do not only act as a unit transferring electrons from sodium borohydride towards methylene blue but can promote the electron transfer upon plasmonic excitation. By testing different particle shapes, we could indeed demonstrate an effect of the particle shape by excluding the impact of surface area and/or surface ligands. All nanoparticle solutions showed a higher methylene blue turnover than their reference, whereby gold nanoprisms exhibited 100% turnover as no further methylene blue absorption peak was detected. The reaction rate constant k was also determined and revealed overall quicker reactions when gold or bimetallic nanoparticles were added as a catalyst, and again these were highest for nanoprisms. Furthermore, when comparing gold and bimetallic nanorods, it could be shown that through the addition of the catalytically active second metal platinum or palladium, the dye turnover was accelerated and degradation rate constants were higher compared to those of pure gold nanorods. The results explore the catalytic activity of nanoparticles, and assist in exploring further catalytic applications.

In this study, a novel approach to create arbitrarily shaped 3D hydrogel objects is presented, wherein freeform two-photon polymerization (2PP) is enabled by the combination of a photosensitive hydrogel and an intrinsic support matrix. This way, topologies without physical contact such as a highly porous 3D network of concatenated rings were realized, which are impossible to manufacture with most current 3D printing technologies. Micro-Raman and nanoindentation measurements show the possibility to control water uptake and hence tailor the Young's modulus of the structures via the light dosage, proving the versatility of the concept regarding many scaffold characteristics that makes it well suited for cell specific cell culture as demonstrated by cultivation of human induced pluripotent stem cell derived cardiomyocytes.

Microfluidic techniques allow for the tailored construction of specific microparticles, which are becoming increasingly interesting and relevant. Here, using a microfluidic hole-plate-device and thermal-initiated free radical polymerization, submicrometer polymer particles with a highly textured surface were synthesized. Two types of monomers were applied: (1) methylmethacrylate (MMA) combined with crosslinkers and (2) divinylbenzene (DVB). Surface texture and morphology can be influenced by a series of parameters such as the monomer-crosslinker-solvent composition, surfactants, and additives. Generally, the most structured surfaces with the simultaneously most uniform particles were obtained in the DVB-toluene-nonionic-tensides system. In a second approach, poly-MMA (PMMA) particles were used to build aggregates with bigger polymer particles. For this purpose, tripropyleneglycolediacrylate (TPGDA) particles were synthesized in a microfluidic co-flow arrangement and polymerized by light- irradiation. Then, PMMA particles were assembled at their surface. In a third step, these composites were dispersed in an aqueous acrylamide-methylenebisacrylamide solution, which again was run through a co-flow-device and photopolymerized. As such, entities consisting of particles of three different size ranges - typically 0.7/30/600 [my]m - were obtained. The particles synthesized by both approaches are potentially suitable for loading with or incorporation of analytic probes or catalysts such as dyes or metals.

Effective targeting of metastasis is considered the main problem in cancer therapy. The development of herbal alkaloid Berberine (Ber)-based anticancer drugs is limited due to Ber’ low effective concentration, poor membrane permeability, and short plasma half-life. To overcome these limitations, we used Ber noncovalently bound to C60 fullerene (C60). The complexation between C60 and Ber molecules was evidenced with computer simulation. The aim of the present study was to estimate the effect of the free Ber and C60-Ber nanocomplex in a low Ber equivalent concentration on Lewis lung carcinoma cells (LLC) invasion potential, expression of epithelial-to-mesenchymal transition (EMT) markers in vitro, and the ability of cancer cells to form distant lung metastases in vivo in a mice model of LLC. It was shown that in contrast to free Ber its nanocomplex with C60 demonstrated significantly higher efficiency to suppress invasion potential, to downregulate the level of EMT-inducing transcription factors SNAI1, ZEB1, and TWIST1, to unblock expression of epithelial marker E-cadherin, and to repress cancer stem cells-like markers. More importantly, a relatively low dose of C60-Ber nanocomplex was able to suppress lung metastasis in vivo. These findings indicated that сomplexation of natural alkaloid Ber with C60 can be used as an additional therapeutic strategy against aggressive lung cancer.

Paper presents the results of experimental investigations of magnetoresistance of filled with iron multi-walled carbon nanotubes. Multi-walled carbon nanotubes have been prepared by pyrolysis of benzene in a tubular quartz furnace at a temperature of 950&ring;C with use ferrocene as a source of iron. The obtained by this method carbon nanotubes contain in the inner cavity the particles of the magnetic phase, namely iron, iron carbide and iron oxides in various concentrations. The electrical resistance of bulk specimens of modified carbon nanotubes have been carried out in the temperature interval from 4.2 K to 293 K and in magnetic field up to 2 T. It is shown that magnetoresistance of modified carbon nanotubes is determined by a combination of two effects: the giant magnetoresistance effect and anisotropic magnetoresistance effect, moreover, the relative contribution of each effect depends on the concentration of the magnetic phase.

Based on WHO reports the new SARS-CoV-2 coronavirus is currently widespread all over the world. So far > 162 million cases have been confirmed, including > 3 million deaths. Because of the pandemic still spreading across the globe the accomplishment of computational methods to find new potential mechanisms of virus inhibitions is necessary. According to the fact that C60 fullerene (a sphere-shaped molecule consisting of carbon) has shown inhibitory activity against various protein targets, here the analysis of the potential binding mechanism between SARS-CoV-2 proteins 3CLpro and RdRp with C60 fullerene was done; it has resulted in one and two possible binding mechanisms, respectively. In the case of 3CLpro, C60 fullerene interacts in the catalytic binding pocket. And for RdRp in the first model C60 fullerene blocks RNA synthesis pore and in the second one it prevents binding with Nsp8 co-factor (without this complex formation, RdRp can't perform its initial functions). Then the molecular dynamics simulation confirmed the stability of created complexes. The obtained results might be a basis for other computational studies of 3CLPro and RdRp potential inhibition ways as well as the potential usage of C60 fullerene in the fight against COVID-19 disease.

Colloidal metal nanoparticles in an electrolyte environment are not only electrically charged but also electrochemically active objects. They have the typical character of metal electrodes with ongoing charge transfer processes on the metal/liquid interface. This picture is valid for the equilibrium state and also during the formation, growth, aggregation or dissolution of nanoparticles. This behavior can be understood in analogy to macroscopic mixed-electrode systems with a free-floating potential, which is determined by the competition between anodic and cathodic partial processes. In contrast to macroscopic electrodes, the small size of nanoparticles is responsible for significant effects of low numbers of elementary charges and for self-polarization effects as they are known from molecular systems, for example. The electrical properties of nanoparticles can be estimated by basic electrochemical equations. Reconsidering these fundamentals, the assembly behavior, the formation of nonspherical assemblies of nanoparticles and the growth and the corrosion behavior of metal nanoparticles, as well as the formation of core/shell particles, branched structures and particle networks, can be understood. The consequences of electrochemical behavior, charging and self-polarization for particle growth, shape formation and particle/particle interaction are discussed.

We present a new methodological approach for the assessment of the susceptibility of Rhodococcus erythropolis strains from specific sampling sites in response to increasing heavy metal concentration (Cu2+, Ni2+, and Co2+) using the droplet-based microfluid technique. All isolates belong to the species R. erythropolis identified by Sanger sequencing of the 16S rRNA. The tiny step-wise variation of metal concentrations from zero to the lower mM range in 500 nL droplets not only provided accurate data for critical metal ion concentrations but also resulted in a detailed visualization of the concentration-dependent response of bacterial growth and autofluorescence activity. As a result, some of the isolates showed similar characteristics in heavy metal tolerance against Cu2+, Ni2+, and Co2+. However, significantly different heavy metal tolerances were found for other strains. Surprisingly, samples from the surface soil of ancient copper mining areas supplied mostly strains with a moderate sensitivity to Cu2+, Ni2+, and Co2+, but in contrast, a soil sample from an excavation site of a medieval city that had been covered for about eight centuries showed an extremely high tolerance against cobalt ion (up to 36 mM). The differences among the strains not only may be regarded as results of adaptation to the different environmental conditions faced by the strains in nature but also seem to be related to ancient human activities and temporal partial decoupling of soil elements from the surface. This investigation confirmed that microfluidic screening offers empirical characterization of properties from same species which has been isolated from sites known to have different human activities in the past.

A new water-soluble thermosensitive star-like copolymer, dextran-graft-poly-N-iso-propilacrylamide (D-g-PNIPAM), was created and characterized by various techniques (size-exclusion chromatography, differential scanning calorimetry, Fourier-transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS) spectroscopy). The viability of cancer cell lines (human transformed cervix epithelial cells, HeLa) as a model for cancer cells was studied using MTT and Live/Dead assays after incubation with a D-g-PNIPAM copolymer as a carrier for the drug doxorubicin (Dox) as well as a D-g-PNIPAM + Dox mixture as a function of the concentration. FTIR spectroscopy clearly indicated the complex formation of Dox with the D-g-PNIPAM copolymer. The size distribution of particles in Hank’s solution was determined by the DLS technique at different temperatures. The in vitro uptake of the studied D-g-PNIPAM + Dox nanoparticles into cancer cells was demonstrated by confocal laser scanning microscopy. It was found that D-g-PNIPAM + Dox nanoparticles in contrast to Dox alone showed higher toxicity toward cancer cells. All of the aforementioned facts indicate a possibility of further preclinical studies of the water-soluble D-g-PNIPAM particles’ behavior in animal tumor models in vivo as promising carriers of anticancer agents.

An automated microfluidic system with computer-controlled syringe pumps was applied for screening a three-dimensional concentration space for the formation of binary gold-platinum metal nanorods. Leveraging the micro segmented flow technique, precise residence and reactant addition timings as well as concentration spaces were addressed. The density and thickness of quasi-isotropic platinum shells on gold nanorod cores were tuned from isolated spots to a dense arrangement of high-aspect-ratio columns. The changing optical properties of the particles in the platinum deposition were used for monitoring the reaction progress and the products by the means of a fiber based micro flow-through spectrophotometer allowing to optimize process times. From our data, we propose an electrochemical model, postulating a diode-like effect and limitations for the formation of Pt nuclei on the gold surface and the formation of nano local elements. This point of view is supported by the observed decoration effects of gold facets and to the formation of columnar structures of the platinum shell.

A major challenge in the use of HepG2 cell culture models for drug toxicity screening is their lack of maturity in 2D culture. 3D culture in Matrigel promotes the formation of spheroids that express liver-relevant markers, yet they still lack various primary hepatocyte functions. Therefore, alternative matrices where chemical composition and materials properties are controlled to steer maturation of HepG2 spheroids remain desired. Herein, a modular approach is taken based on a fully synthetic and minimalistic supramolecular matrix based on squaramide synthons outfitted with a cell-adhesive peptide, RGD for 3D HepG2 spheroid culture. Co-assemblies of RGD-functionalized squaramide-based and native monomers resulted in soft and self-recovering supramolecular hydrogels with a tunable RGD concentration. HepG2 spheroids are self-assembled and grown ( 150 m) within the supramolecular hydrogels with high cell viability and differentiation over 21 days of culture. Importantly, significantly higher mRNA and protein expression levels of phase I and II metabolic enzymes, drug transporters, and liver markers are found for the squaramide hydrogels in comparison to Matrigel. Overall, the fully synthetic squaramide hydrogels are proven to be synthetically accessible and effective for HepG2 differentiation showcasing the potential of this supramolecular matrix to rival and replace naturally-derived materials classically used in high-throughput toxicity screening.

The east and southeast rim of Harz mountains (Germany) are marked by a high density of former copper mining places dating back from the late 20th century to the middle age. A set of 18 soil samples from pre- and early industrial mining places and one sample from an industrial mine dump have been selected for investigation by 16S rRNA and compared with six samples from non-mining areas. Although most of the soil samples from the old mines show pH values around 7, RNA profiling reflects many operational taxonomical units (OTUs) belonging to acidophilic genera. For some of these OTUs, similarities were found with their abundances in the comparative samples, while others show significant differences. In addition to pH-dependent bacteria, thermophilic, psychrophilic, and halophilic types were observed. Among these OTUs, several DNA sequences are related to bacteria which are reported to show the ability to metabolize special substrates. Some OTUs absent in comparative samples from limestone substrates, among them Thaumarchaeota were present in the soil group from ancient mines with pH > 7. In contrast, acidophilic types have been found in a sample from a copper slag deposit, e.g., the polymer degrading bacterium Granulicella and Acidicaldus, which is thermophilic, too. Soil samples of the group of pre-industrial mines supplied some less abundant, interesting OTUs as the polymer-degrading Povalibacter and the halophilic Lewinella and Halobacteriovorax. A particularly high number of bacteria (OTUs) which had not been detected in other samples were found at an industrial copper mine dump, among them many halophilic and psychrophilic types. In summary, the results show that soil samples from the ancient copper mining places contain soil bacterial communities that could be a promising source in the search for microorganisms with valuable metabolic capabilities.

In the course of screening the surface soils of ancient copper mines and smelters (East Harz, Germany) an aerobic, non-motile and halotolerant actinobacterium forming small rods or cocci was isolated. The strain designated F300T developed creamy to yellow colonies on tryptone soy agar and grew optimally at 28 &ring;C, pH 7-8 and with 0.5-2% (m/v) NaCl. Its peptidoglycan was of type A4α l-Lys-l-Glu (A11.54). The menaquinone profile was dominated by MK-8(II, III-H4) and contained minor amounts of MK-8(H2), MK-8(H6) and MK-9(H4). The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, mono and diacylated phosphatidylinositol dimannosides, and components that were not fully characterized, including two phospholipids, two glycolipids and an uncharacterized lipid. Major whole-cell sugars were rhamnose and ribose. The fatty acid profile contained mainly iso and anteiso branched fatty acids (anteiso-C15:0, iso-C14:0) and aldehydes/dimethylacetals (i.e. not fatty acids). Sequence analysis of its genomic DNA and subsequent analysis of the data placed the isolate in the group currently defined by members of the genera Ruania and Haloactinobacterium (family Ruaniaceae , order Micrococcales ) as a sister taxon to the previously described species Haloactinobacterium glacieicola , sharing an average nucleotide identity and average amino acid identity values of 85.3 and 85.7%, respectively. Genotypic and chemotaxonomic analyses support the view that strain F300T (=DSM 108350T=CIP 111667T) is the type strain of a new genus and new species for which the name Occultella aeris gen. nov., sp. nov. is proposed. Based on revised chemotaxonomic and additional genome based data, it is necessary to discuss and evaluate the results in the light of the classification and nomenclature of members of the family Ruaniaceae , i.e. the genera Haloactinobacterium and Ruania . Consequently, the reclassification of Haloactinobacterium glacieicola as Occultella glacieicola comb. nov. and Haloactinobacterium album as Ruania alba comb. nov., with an emended description of the genus Ruania are proposed.,

External mechanical stimuli represent elementary signals for living cells to adapt to their adjacent environment. These signals range from bulk material properties down to nanoscopic surface topography and trigger cell behaviour. Here, we present a novel approach to generate tailored surface roughnesses in the nanometer range to tune surface properties by particle size and volume ratio. Time-resolved local mean-squared displacement (LMSD) analysis of amoeboid cell migration reveals that nanorough surfaces alter effectively cell migration velocities and the active cell migration phases. Since the UV curable composite material is easy to fabricate and can be structured via different light based processes, it is possible to generate hierarchical 3D cell scaffolds for tissue engineering or lab-on-a-chip applications with adjustable surface roughness in the nanometre range.

The application of double electron-electron resonance (DEER) with site-directed spin labeling (SDSL) to measure distances in proteins and protein complexes in living cells puts rigorous restraints on the spin-label. The linkage and paramagnetic centers need to resist the reducing conditions of the cell. Rigid attachment of the probe to the protein improves precision of the measured distances. Here, three two-armed GdIII complexes, GdIII-CLaNP13a/b/c were synthesized. Rather than the disulfide linkage of most other CLaNP molecules, a thioether linkage was used to avoid reductive dissociation of the linker. The doubly GdIII labeled N55C/V57C/K147C/T151C variants of T4Lysozyme were measured by 95 GHz DEER. The constructs were measured in vitro, in cell lysate and in Dictyostelium discoideum cells. Measured distances were 4.5 nm, consistent with results from paramagnetic NMR. A narrow distance distribution and typical modulation depth, also in cell, indicate complete and durable labeling and probe rigidity due to the dual attachment sites.

Micro and nanoparticles are not only understood as components of materials but as small functional units too. Particles can be designed for the primary transduction of physical and chemical signals and, therefore, become a valuable component in sensing systems. Due to their small size, they are particularly interesting for sensing in microfluidic systems, in microarray arrangements and in miniaturized biotechnological systems and microreactors, in general. Here, an overview of the recent development in the preparation of micro and nanoparticles for sensing purposes in microfluidics and application of particles in various microfluidic devices is presented. The concept of sensor particles is particularly useful for combining a direct contact between cells, biomolecules and media with a contactless optical readout. In addition to the construction and synthesis of micro and nanoparticles with transducer functions, examples of chemical and biological applications are reported.

Previously, we have demonstrated that water dispersible single-walled carbon nanotubes (SWCNTs) may be used in low therapeutic doses in antihypertensive therapy as promising agents capable of activating constitutive nitric oxide synthase (NOS) in spontaneously hypertensive rats, thus increasing the NO production in central and peripheral elements of the cardiovascular system [1]. Here we confirm this effect by docking and molecular dynamics simulations, clearly showing that SWCNTs may interact with NOS and guanylate cyclase molecular structures.

Background: C60 fullerenes and their derivatives are actively investigated for the use in neuroscience. Applications of these nanoscale materials require the examination of their interaction with different neural cells, especially with microglia, because these cells, like other tissue resident phagocytes, are the earliest and most sensitive responders to nanoparticles. The aim of this study was to investigate the effect of C60 fullerene and its nanocomplex with doxorubicin (Dox) on the metabolic profile of brain-resident phagocytes - microglia - in vitro. Methods: Resting microglial cells from adult male Wistar rats were used in experiments. Potential C60 fullerene targets in microglial cells were studied by computer simulation. Microglia oxidative metabolism and phagocytic activity were examined by flow cytometry. Griess reaction and arginase activity colorimetric assay were used to explore arginine metabolism. Results: C60 fullerene when used alone did not influence microglia oxidative metabolism and phagocytic activity but shifted arginine metabolism toward the decrease of NO generation. Complexation of C60 fullerene with Dox (C60-Dox) potentiated the ability of the latter to stimulate NO generation. Conclusion: The capability of C60 fullerenes used alone to cause anti-inflammatory shift of microglia arginine metabolism makes them a promising agent for the correction of neuroinflammatory processes involved in neurodegeneration. The potentiating action of C60 fullerene on the immunomodulatory effect of Dox allows us to consider the C60 molecule as an attractive vehicle for this antitumor agent.

Nanoparticles with the sizes in the range (20-30) nm of apatite-type Na+,Zn2+,CO32--doped calcium phosphates were prepared from aqueous solution of Na+-Ca2+-Zn2+-NO3--CO32--PO43- system at molar ratios Ca2+/PO43- =1.67, CО32-/РО43- = 1, Zn2+:Ca2+ = 1:100 or 2:100. The elemental analysis showed growth of Zn2+ content in composition of samples from 0.61 to 1.95 wt% at increasing of Zn2+ amount in an initial solution. According to FTIR and Raman data, B-type substitution of PO43- by CO32- realized in apatite-type calcium phosphates. The mechanical properties study for prepared phases showed the dependence of Young's modulus and compressive strength on Zn2+ amount in their composition. Growth of S. epidermidis after the contact with synthesized apatite containing Na+ (0.25 wt%), Zn2+ (0.61 wt%) and CO32- (1.18 wt%) was significantly delayed with an extension of lag time from 1 to 13-14 h. The prepared sample can be considered as a new prospective biomaterial with antibacterial potential.

16S rRNA profiling has been applied for the investigation of bacterial communities of surface soil samples from forest-covered areas of ten prehistorical ramparts from different parts of Thuringia. Besides the majority bacterial types that are present in all samples, there could be identified bacteria that are highly abundant in some places and absent or low abundant in others. These differences are mainly related to the acidity of substrate and distinguish the communities of lime stone hills from soils of sand/quartzite and basalt hills. Minority components of bacterial communities show partially large differences that cannot be explained by the pH of the soil or incidental effects, only. They reflect certain relations between the communities of different places and could be regarded as a kind of signature-like patterns. Such relations had also been found in a comparison of the data from ramparts with formerly studied 16S rRNA profiling from an iron-age burial field. The observations are supporting the idea that a part of the components of bacterial communities from soil samples reflect their ecological history and can be understood as the "ecological memory" of a place. Probably such memory effects can date back to prehistoric times and might assist in future interpretations of archaeological findings on the prehistoric use of a place, on the one hand. On the other hand, the genetic profiling of soils of prehistoric places contributes to the evaluation of anthropogenic effects on the development of local soil bacterial diversity.

Fluoreszenzdetektion hat eine große Bedeutung in biologischen und medizinischen Anwendungen für die Analyse verschiedener Farbstoffe und Zellkulturen. Durch Kombination von Fluidik, Optik und Elektronik ist die Realisierung eines kompakten und hochempfindlichen Messsystems möglich, welches vorteilhaft bei der Messung von Proben mit kleinen Volumina ist.

We report on the fabrication of an enzyme-free electrochemical sensor for glucose based on a printed film consisting of multi-walled carbon nanotubes (MWCNTs). The MWCNT-based film can be produced by means of a flexographic printing process on a polycarbonate (PC) substrate. The electrochemical response of the MWCNT-based film (referred to as MWCNT-PC) towards the oxidation of glucose at pH 7 was studied by means of cyclic voltammetry and electrochemical impedance spectroscopy. The MWCNT-PC film exhibits substantial electrocatalytic activity towards the oxidation of glucose at an anodic potential of 0.30 V (vs. Ag/AgCl). The findings reveal that the MWCNT-PC film enables non-enzymatic sensing of glucose with a detection limit as low as 2.16 mu M and a sensitivity of 1045 mu Aa (TM) mM(-1)a (TM) cm(-2).

Novel films consist of multi-walled carbon nanotubes (MWCNT) were fabricated by means of catalytic chemical vapor deposition (CVD) technique with decomposition of either acetonitrile (ACN) or benzene (BZ) using ferrocene (FeCp2) as catalyst. The electrochemical and thermodynamic behavior of the ferrocyanide/ferricyanide, [Fe(CN)(6)](3-/4-) redox couple on synthesized MWCNT-based films was investigated by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques at T = (278.15, 283.15, 293.15, and 303.15) K. The redox couple [Fe(CN)(6)](3-/4-) behaves quasi-reversibly on fabricated MWCNT-based films and its reversibility is enhanced upon increasing temperature. Namely, the findings establish that with the rise in temperature the barrier for interfacial electron transfer decreases, leading, consequently, to an enhancement of the kinetics of the charge transfer process. According to thermodynamics the equilibrium of the redox process is shifted towards the formation of [Fe(CN)(6)](3-) at elevated temperatures.

The aim of the present work was the investigation of the interaction of water-soluble pristine fullerenes C-60 with bimolecular lipid model membrane (BLM) and cellular plasma membrane (PM). The findings demonstrate that the fullerenes C-60 at low concentrations, namely in the concentration range of 1.0 x 10(-4)-1.0 mg . ml(-1), are preferentially incorporated into the hydrophobic region of BLM, increasing, thus, its specific conductivity and specific capacity. Furthermore, upon interaction of fullerenes C-60 with PM, pores or other type of local defects are formed, which are wide enough in order to permit the passage of water molecules across the cell membrane resulting to the externalization of phosphatidylserine from the inner to the outer PM leaflet.

Nitrogen-doped multi-walled carbon nanotubes (N-MWCNT) were synthesized by means of catalytic chemical vapor deposition technique using acetonitrile as carbon source material and ferrocene as catalyst. The structure of the synthesized N-MWCNT was characterized by means of microscopic (SEM, HRTEM) as well as spectroscopic (FTIR, Raman) techniques. Furthermore, the specific resistivity and the electrochemical properties of N-MWCNT were investigated and compared with those of pristine MWCNT. The results are discussed in terms of structural differences between pristine MWCNT and N-MWCNT.

The effect of the anticancer drug-doxorubicin (Dox) on hydration properties of a nanocomposite material deposited on silica and modified by small amount of DNA (0.6 wt%) was studied by means of (1)H NMR spectroscopy at low temperatures (in the range of 200-280 K). Signals of either weakly (WAW) or strongly (SAW) associated water, as well as water associated with electrondonor groups of the composite surface (ASW), were observed. The findings reveal that, depending on the temperature and the composition of the dispersion medium, fast molecular exchange takes place between different forms of interphase water. The presence of Dox (0.1-0.2 wt%) in the dispersion medium leads to change of the relative concentrations of different forms of water.

The residence time distribution (RTD) characteristics of three microreactors containing different passive mixing structures, namely, a three dimensional serpentine structure, a split-and-recombine structure and a staggered herringbone structure, were investigated and compared. An experimental input-response technique was applied which required deconvolution of the measured data by modeling of the RTD. The proposed technique provides useful information on optimized application and operation of microfluidic devices. The serpentine reactor and the split-and-recombine reactor show improvement in RTD behaviour, i.e., narrowing of RTD curves, at Re-numbers > 30 due to effective transversal mixing and therefore reduced axial dispersion. In the case of the staggered herringbone structure, dead volumes could be observed which considerably affect the RTD.

The cultivation of the monocellular green alga Chlorella vulgaris was implemented into microfluid segments to demonstrate the possibility of an automated screening of toxic effects of the common algaecide CuCl2. Therefore, the nutritional as well as light and carbon dioxide requirements of the algae had to be adapted to the microfluidic device. Generally, sequences of about 350 fluid segments with single volumes of about 500 nL were applied for the dose-response experiments. The growth of algae cultures inside microfluidic segments was noninvasively measured by microflow through techniques using two different optical channels. A multi-endpoint detection was realized by the photometric characterization of cell density by transmission measurements and the measurement of density of autofluorescent cells. The different methods revealed comparable half maximal effective concentrations (EC50) in the range between 34.6 and 39.9 mg/mL for the toxicity of CuCl2 to the green algae C. vulgaris. By reference experiments in microtiter plates lower EC50 were achieved presumably caused by increased alkalinity of the growth medium due to higher photosynthesis. The results show that the microsegmented flow technique is well suited for the automated determination of dose/response functions for microorganisms like C. vulgaris and for the application of multi-endpoint procedures at the nanoliter scale.

Films of vertically aligned multi-walled carbon nanotubes (MWCNT) were selectively synthesized on silicon dioxide substrate by catalytic chemical vapor deposition using either benzene or acetonitrile as carbon source and ferrocene (1% w/w) as catalyst. The MWCNT were extensively characterized by using scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Raman spectroscopy. In order to examine the prospective application of the fabricated MWCNT films for the detection of electro-active compounds in organic solvent media, electrochemical studies of the oxidation of cobaltocene (CoCp(2)) to cobaltocenium cation (CoCp (2) (+)) (Cp = cyclopentadienyl anion) in acetonitrile were performed on these films. For this purpose, cyclic voltammetry and electrochemical impedance spectroscopy were employed. The electrochemical parameters for the CoCp (2) (+/0) couple in acetonitrile were derived and compared with those obtained using a conventional glassy carbon electrode. The results demonstrate that the synthesized MWCNT films are promising electrode materials for the electrochemical detection of electro-active species in organic solvents. The MWCNT film formed upon decay of benzene has higher capacitance, less Warburg impedance, and less charge transfer resistance, and consequently it provides faster electron transfer kinetics.

Solutions of palladium chloride in acetonitrile are investigated by means of electrospray ionization mass spectrometry (ESI-MS). In contrast to several other metal salts previously investigated using ESI-MS, PdCl(2)2 has a pronounced tendency for aggregation to yield [Pd(m)Cl(2m-1)(CH(3)CN)(n)](+) clusters in the positive ion mode and [Pd(m)Cl(2m+1)](-) clusters when the negative ions are sampled, respectively. The observation of these oligomers parallels polymeric structures of PdCl(2) in the solid phase. The positive ions are most abundant for m = 2 and generally associated with several molecules of the solvent, whereas many different cluster sizes occur for the anions which generally do not appear as solvent associates. Parallel conductivity measurements in the condensed phase lend support to a pronounced tendency for aggregation of PdCl(2) in acetonitrile solution.

In the present article, the electrochemical sensitivity and response of films consisting of carbon nanoparticles were examined to test their potential applications as electrode materials for the construction of electrochemical sensors. For this purpose, a film of vertically aligned multi-walled carbon nanotubes (MWCNTs) on silicon dioxide substrate was synthesized by means of catalytic chemical vapor deposition (CVD) at 900oC using ferrocene (FeCp2) as catalyst and acetonitrile (ACN) as a carbon source. Furthermore, bucky-paper (BP) film was produced upon ultrasonic treatment of aqueous solution of single-walled carbon nanotubes (SWCNTs) in the presence of sodium dodecyl sulfate (SDS) micelle. In order to examine the electrochemical activity of the fabricated films, electrochemical studies of the oxidation of ferrocene (FeCp2) to ferrocenium cation (FeCp2+) (where Cp denotes cyclopentadienyl anion) in ACN containing n-tetrabutylammonium hexafluorophosphat (NBu4PF6) as supporting electrolyte were performed. For the electrochemical experiments the techniques of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed. The electrochemical parameters of the FeCp2+/0 redox couple in ACN on the fabricated films were determined and compared with those obtained using conventional glassy carbon (GC) electrode. The results demonstrate that the FeCp2+/0 redox couple exposes Nernstian response on either MWCNT or GC electrodes while its response on BP film can be recognized as near Nernstian. The findings verify that the synthesized MWCNT and BP films hold promising and important applications in electro-analytical chemistry.

The molar conductivities (Lambda) of aqueous solutions of silver nitrate and thallium nitrate were measured in the temperature range from 291.15 K to 314.15 K. The Lambda values were analyzed using the Lee-Wheaton model, and the limiting molar conductivities (Lambda(o)) as well as the association equilibrium constants (K(A)) were derived. The center-to-center distances (alpha) of the formed ion pairs were considered to be equal to the Bjerrum's distance. The limiting ion conductivities (lambda(+/-)) were determined. The thermodynamic functions, Gibbs energy (Delta G(A)), enthalpy (Delta H(A)), and entropy (Delta S(A)) for the ion-pair formation process were determined as well. The results are discussed in terms of ion-ion and ion-solvent interactions.

Magnetic properties of multi-walled carbon nanotubes (MWCNT) modified with cobalt were studied in detail in the temperature range (4.2-290) K. MWCNT which encapsulate Co nanoparticles were obtained using CVD methods. The low temperature SQUID magnetization measurements were supplemented by structural investigations with thermogravimetric analysis, HRTEM and SEM.

This study was performed to measure the thermal diffusivity of different types of nanocarbon composites. Thermoexfoliated graphite (TEG), ultrasonically dispersed TEG, and multiwalled carbon nanotubes were used as fillers in epoxy polymer matrixes. The nanocarbon filler content was 1-10 wt%. The temperature dependence of the thermal conductivity and the heat capacity were extensively characterized in the temperature range between 150 and 425 K. For this purpose, the thermal diffusivity of the composites was investigated by two experimental methods: dynamic A-calorimeter and photoacoustic. The comparative analysis of thermal diffusivity of compacted TEG samples with different densities and of nanocarbon-epoxy with different filler content was carried out. It was found that for the composites with a low distribution of the nanocarbon filler, the thermal diffusivity increases and that the value is determined by the structural and morphological properties of the filler. The orientation function for the TEG-epoxy composites and the compact TEG samples differs due to the epoxy matrix that reduced anisotropy of the composite. POLYM. COMPOS., 2011. (C) 2010 Society of Plastics Engineers

The material properties of low-temperature co-fired ceramics (LTCCs) enable new application areas beyond the use as basic material for high-density circuits. Therefore, LTCCs are increasingly used for microfluidic applications. A modular LTCC-based microreaction system is presented in this article. One focal point of our work was the development of a connecting system for these ceramic fluidic modules. Importance was attached to solid mechanical design, good temperature resistance of fluidic and electrical connections, and minimized dead volume. In contrast to LTCC-based substrates with only electrical circuits, integration of fluidic components makes great demands, especially on the mechanical processing of the green tapes. Mechanical processing of LTCC was made by laser cutting or laser ablation. Single modules and a complete system are the subject of chemical characterization. LTCC-based mixer structures are characterized using the VillermauxDushman method. The functionality of the whole system is shown with an example reaction.

Gas chromatograph, gas-sensitive semiconducting layers, heterogeneous catalysis, volatile compounds, lipid-containing foods, oxidative ageing, vegetable oils, oxidic semiconductors, quality control, resistive gas sensors