Schönherr, Holger
5 results
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Publication Access status: Metadata only , Anodic Aluminum Oxide Membrane Assisted Extrusion of Polymer Solutions for Hydrogel FormationThe potential of polymeric nanostructures obtained by extruding polymer solutions through reusable anodic aluminum oxide (AAO) nanopores for the fabrication of nanostructures is investigated systematically to be able to unveil the potential impact of structure on cell culturing. Thus, nanostructured Na‐alginate and poly(vinyl alcohol) (PVA) polymers as well as blended alginate/PVA hydrogels are fabricated. Na‐alginate and PVA fibers with different dimensions can be obtained. By extruding Na‐alginate solutions into a non‐solvent also networks of uniform nanofibers (diameter <20 nm) are generated. PVA forms agglomerations of nanofibers and nanopArticles with diameter >100 nm. In ADDition, cell line‐dependent behavior of the cross‐linked PVA/alginate nanofibers is observed, which is characterized by reduced cell adhesion and cluster formation of PaTu 8988t cells on these blend nanofibers compared to normal cell adhesive behavior of NIH 3T3 cells.Source Type:Article4 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Boosting the Cell Harvesting Performance of Poly(di(ethylene glycol)methyl ether methacrylate) Cell Release Layers via Copolymerization of Photo‐ and Thermoresponsive MonomersThe performance of the cell‐selective thermoresponsive poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) cell harvest system is shown to be drastically enhanced by exploiting the combination of photoresponsive spiropyran derivates and PDEGMA in copolymerized brushes. The analysis of copolymerized 1′‐(2‐methacryloxyethyl)‐3′,3′‐dimethyl‐6‐nitrospiro(2 H ‐1‐benzopyran‐2,2′‐indoline) (SPMA) (DEMGA) di(ethylene glycol)methyl ether methacrylate brushes revealed that a minor adjustment of the SPMA/DEGMA ratios results in a significant alternation of wettability as well as protein adsorption, when switching the temperature from 37 to 22 °C and alternately irradiating using different light wavelengths (from 530 to 365 nm). Thin P(SPMA‐ co ‐DEGMA) layers supported pancreatic tumor PaTu 8988t cells with high cell viability. Copolymer layers with 2.5% SPMA/DEGMA led to the highest efficiency of enzyme‐free cell release with very good cell viability. The release is induced by cooling the cell culture medium to 22 °C and irradiating the surface with 365 nm light. Compared to neat PDEGMA, the P(SPMA‐ co ‐DEGMA) layers showed a threefold increase in the speed of the change of cell morphology of the attached cells and a >5 times increased fraction of detached cells, which underlines the potential of these dual responsive PDEGMA systems for optimized performance in the facile capture, culture, and release of different cell lines.Source Type:Article2 - Some of the metrics are blocked by yourconsent settings
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Publication Access status: Metadata only , Interlayer Affected Diamond Electrochemistry(2024); ; ; ; Diamond electrochemistry is primarily influenced by quantities of sp 3 ‐carbon, surface terminations, and crystalline structure. In this work, a new dimension is introduced by investigating the effect of using substrate‐interlayers for diamond growth. Boron and nitrogen co‐doped nanocrystalline diamond (BNDD) films are grown on Si substrate without and with Ti and Ta as interlayers, named BNDD/Si, BNDD/Ti/Si, and BNDD/Ta/Ti/Si, respectively. After detailed characterization using microscopies, spectroscopies, electrochemical techniques, and density functional theory simulations, the relationship of composition, interfacial structure, charge transport, and electrochemical properties of the interface between diamond and metal is investigated. The BNDD/Ta/Ti/Si electrodes exhibit faster electron transfer processes than the other two diamond electrodes. The interlayer thus determines the intrinsic activity and reaction kinetics. The reduction in their barrier widths can be attributed to the formation of TaC, which facilitates carrier tunneling, and simultaneously increases the concentration of electrically active defects. As a case study, the BNDD/Ta/Ti/Si electrode is further employed to assemble a redox‐electrolyte‐based supercapacitor device with enhanced performance. In summary, the study not only sheds light on the intricate relationship between interlayer composition, charge transfer, and electrochemical performance but also demonstrates the potential of tailored interlayer design to unlock new capabilities in diamond‐based electrochemical devices.Source Type:Article5 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , On‐Demand Cell Sheet Release with Low Density Peptide‐Functionalized Non‐LCST Polymer BrushesCell sheet harvesting offers a great potential for the development of new therapies for regenerative medicine. For cells to adhere onto surfaces, proliferate, and to be released on demand, thermoresponsive polymeric coatings are generally considered to be required. Herein, an alternative approach for the cell sheet harvesting and rapid release on demand is reported, circumventing the use of thermoresponsive materials. This approach is based on the end‐group biofunctionalization of non‐thermoresponsive and antifouling poly(2‐hydroxyethyl methacrylate) (p(HEMA)) brushes with cell‐adhesive peptide motifs. While the nonfunctionalized p(HEMA) surfaces are cell‐repellant, ligation of cell‐signaling ligand enables extensive attachment and proliferation of NIH 3T3 fibroblasts until the formation of a confluent cell layer. Remarkably, the formed cell sheets can be released from the surfaces by gentle rinsing with cell‐culture medium. The release of the cells is found to be facilitated by low surface density of cell‐adhesive peptides, as confirmed by X‐ray photoelectron spectroscopy. Additionally, the developed system affords possibility for repeated cell seeding, proliferation, and release on previously used substrates without any additional pretreatment steps. This new approach represents an alternative to thermally triggered cell‐sheet harvesting platforms, offering possibility of capture and proliferation of various rare cell lines via appropriate selection of the cell‐adhesive ligand.Source Type:Article4
