Surface in biomedical applications

Microporous and microfibrous surfaces on metals are increasingly used in biomedical applications. A recent review by Wen et al. [60] identified advantages over metals with smooth surfaces which included early better adhesion of biomolecules and cells and firmer fixation of bone or connective tissue. 

The fiber optic refractive index sensor finds use in biomedical applications. It uses a silicon chip with optical waveguides forming ring resonators. When the laser wavelength is scanned, the resonators cause dips in the power transmitted through the device. The wavelength at which these dips occur is a measure of the refractive index of the substance in contact with the chip surface. 

Finally, we note that in a very recent work Heuberger et al. investigated protein-resistant copolymer monolayers of PEG grafted to poly(L-lysine) (PLL) (PLL-g-PEG) in terms of the role of water in surface grafted PEG layers [159], interaction forces and morphology [160], compressibility, temperature dependence and molecular architecture [161], PEG is often used in biomedical applications in order to create protein-resistant surfaces but the mechanisms responsible for the protein-repelling properties of PEG are not fully understood. 

Plasticised PVC sheets were surface modified by nucleophilic substitution of chlorine by azide in aqueous media under phase transfer conditions. The azidated PVC surface was then irradiated by UV light to crosslink the surface. It was found that considerable reduction in the migration of the plasticiser di-(2-ethylhexyl phthalate) could be achieved by this technique, depending on the extent of azidation of the PVC surface and the irradiation dose. After surface modification, there was around 30% reduction in the stress-strain properties of the PVC sheets but these values were still well above the minimum prescribed for PVC used in biomedical applications. 19 refs. 

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