The thermoresponsive polymer poly(N-isopropylacrylamide) was immobilized in a specific pattern on a polystyrene matrix by photolithography. N-Isopropylacrylamide was copolymerized with acrylic acid. The copolymer was coupled with azidoaniline. The low critical solution temperature of the copolymer was lowered by incorporation of azidophenyl groups. The derivatized copolymer was then immobilized on a polystyrene matrix. The surface wettability of the immobilized polystyrene matrix changed with temperature, whereas that of untreated polystyrene matrix was insensitive to temperature. The measurement of contact angle showed that the surface of the immobilized matrix was hydrophobic at 37 °C but hydrophilic at 10 °C. Micropatterned immobilization of the copolymer on the polystyrene matrix surface was carried out using a photomask. The surface micropattern was clearly observed by phase-contrast microscopy at 37 °C. At low temperatures, hydration of graft chains erased the micropattern. The polystyrene matrix with micropatterned surface was applied to tissue engineering. Mouse fibroblast STO cells grown on the surface area, on which thermosensitive polymers were immobilized, were selectively detached by lowering the temperature.

Lewy bodies are considered as the main pathological characteristics of Parkinson's disease (PD). The major component of Lewy bodies is α-synuclein (α-syn). The use of gene therapy that targeting and effectively interfere with the expression of α-syn in neurons has received tremendous attention. In this study, we used magnetic Fe3O4 nanoparticles coated with oleic acid molecules as a nano-carrier. N-isopropylacrylamide derivative (NIPAm-AA) was photo-immobilized onto the oleic acid molecules, and shRNA (short hairpin RNA) was absorbed. The same method was used to absorb nerve growth factor (NGF) to NIPAm-AA to specifically promote neuronal uptake via NGF receptor-mediated endocytosis. Additionally, shRNA plasmid could be released into neurons because of the temperature and pH sensitivity of NIPAm-AA interference with α-syn synthesis. We investigated apoptosis in neurons with abrogated α-syn expression in vitro and in vivo. The results demonstrated that multifunctional superparamagnetic nanoparticles carrying shRNA for α-syn could provide effective repair in a PD model.

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