Ambient temperature ligation of diene functional polymer and peptide strands onto cellulose via photochemical and thermal protocols

Linkert K, Goldmann AS, Börner HG, Barner-Kowollik C.Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76128, Karlsruhe, Germany; Institut für Biologische Grenzflächen, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, In the present contribution, two novel ambient temperature avenues are introduced to functionalize solid cellulose substrates in a modular fashion with synthetic polymer strands (poly(trifluoro ethyl methacrylate), PTFEMA, Mn = 4400 g mol(-1) , Đ = 18) and an Arg-Gly-Asp (RGD) containing peptide sequence. Both protocols rely on a hetero Diels-Alder reaction between an activated thiocarbonyl functionality and a diene species. In the first-thermally activated-protocol, the cellulose features surface-expressed thiocarbonylthio compounds, which readily react with diene terminal macromolecules at ambient temperature. In the second protocol, the reactive ene species are photochemically generated based on a phenacyl sulfide-decorated cellulose surface, which upon irradiation expresses highly reactive thioaldehyde species.

The generated functional hybrid surfaces are characterized in-depth via ToF-SIMS and XPS analysis, revealing the successful covalent attachment of the grafted materials, including the spatially resolved patterning of both synthetic polymers and peptide strands using the photochemical protocol. The study thus provides a versatile platform technology for solid cellulose substrate modification via efficient thermal and photochemical ligation strategies.© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Crack-Photolithography for Membrane-Free Diffusion-Based Micro/Nanofluidic Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil, Recent advances in controlling the cracking phenomena established a novel unconventional fabrication technique to generate mixed-scale patterns/structures with resolution and accuracy comparable to conventional nanofabrication techniques. Here, we adapt our previous cracking-assisted nanofabrication technique (called "crack-photolithography") relying on only the standard photolithography to develop micro/nanofluidic devices with greatly reduced time and cost. The crack-photolithography makes it possible not only to simultaneously produce micropatterns and nanopatterns with various dimensions but also to replicate both of the mixed-scale patterns in a high-throughput manner.

Therefore, a microfluidic channel network can easily be fabricated with a nanochannel array that can function as a nanoporous membrane wherever necessary, which basically plays a key role in diffusion-allowed but convection-suppressed microfluidic devices. In addition, the nanochannel array can manipulate the transport of small molecules by adjusting its dimension and/or number at will, so that nanochannel-array-integrated micro/nanofluidic devices prove even more robust and accurate in diffusion control than conventional membrane-integrated microfluidic devices. As an application of such micro/nanofluidic devices, we employed synthetic bacterial cells and found that their genetic induction and expression are dominated by extracellular diffusive microenvironments that were completely engineered using the nanochannel array. Hence, the crack-photolithography could provide innovative fabrication techniques for unprecedented micro/nanofluidic devices that show substantial potential for a wide range of biological and chemical applications.Heterogeneous mesoporous manganese oxide catalyst for aerobic and additive-free oxidative aromatization of N-heterocycles.Herein, we report a heterogeneous, aerobic, additive-free and environmentally benign catalytic protocol for oxidative aromatization of saturated nitrogen-heterocycles using a mesoporous manganese oxide material. The aromatized products can be separated by easy filtration and the catalyst is reusable for at least four cycles.

Mechanistic investigation provides evidence for radical intermediates, a multi-electron redox cycle between Mn centers, and Biochemical significance of 19-hydroxytestosterone in the process of 19-Hydroxyandrogens are known to be an intermediary metabolite in the aromatizing reaction, though the physiological role of this compound has not yet been clarified. In this study, microsomes obtained from human corpus luteum were incubated with testosterone or 19-hydroxytestosterone (19-OHT) as the substrate to investigate the biochemical significance of 19-OHT in the process of aromatization in the ovary. The inhibitory effects of 4-hydroxyandrostenedione (4-OHA) on the formation of estradiol from testosterone and 19-OHT in human ovary were also investigated. When testosterone was incubated with human ovarian microsomes, 19-OHT and estradiol were identified. When Photoacid Generator -OHT was used as the substrate, the formation of estradiol was demonstrated. To our knowledge, this is the first report to demonstrate the formation of estradiol from 19-OHT in human ovarian tissue. The Km value of aromatase for testosterone on human corpus luteum microsomes was 01 microM.

4-OHA exhibited inhibition with a Ki of 35 nM. With testosterone and 19-OHT as the substrate, the formation of estradiol was also equally inhibited by 4-OHA. A dose dependent inhibition of estradiol formation was observed, with no apparent accumulation of 19-OHT.