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Gewählte Doctoral Thesis:

Nityanand Sharma (2015): Hydrogel Nanostructures for Plasmonic and Biosensor Applications.
Doctoral Thesis - Department für Nanobiotechnologie (DNBT), BOKU-Universität für Bodenkultur, pp 124. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Plasmonics is recently emerged nanophotonics research area that focuses at sub-wavelength confinement of light energy by its coupling to surface plasmons at surfaces of metals. Hybrid responsive polymer-metallic nanostructures represent an attractive class of materials with actively tunable plasmonic properties. Such characteristics may enable new applications of plasmonics in analytics that utilize direct or optical spectroscopy-based detection of molecular analytes as well as in development of novel miniaturized plasmonic components. This thesis describes novel implementations of thermo-responsive N-isopropylacrylamide (pNIPAAm) - based hydrogel to metallic nanostructures that support surface plasmons. It reports means of structuring a photo-crosslinkable pNIPAAm layer with features size as small as 100nm by nano-imprint lithography and laser interference lithography. A new technique for in situ observation of swelling characteristics was developed based on optical waveguide mode-enhanced diffraction measurements. A structure that acts as tunable plasmonic crystal was prepared and by its reversible swelling and collapsing a plasmonic bandgap can be open and closed. In addition, pNIPAAm was employed as "glue" in plasmonic structures to serve as a responsive cushion that tethers a thin metallic film with arrays of nanoholes to a solid glass surface to mediate the extraordinary transmission. pNIPAAm was used as glue to form a composite film with high density of nanoparticles imprinted with a low molecular weight organic molecule. The composite film exhibited highly open architecture through which the target analyte L-Boc-phenylalanine-anilide (L-BFA) can freely diffuse and become affinity capture. Direct detection of affinity binding at concentrations around µM was carried by optical waveguide spectroscopy as the composite film can serve at the same time as large capacity affinity binding matrix and an optical waveguide.


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