PATTERNED IMMOBILIZATION OF THERMORESPONSIVE POLYMER

The thermoresponsive polymer poly(N-isopropylacrylamide) was immobiliz ed in a specific pattern on a polystyrene matrix by photolithography. N-Isopropylacrylamide was copolymerized with acrylic acid. The copolym er was coupled with azidoaniline. The low critical solution temperatur e of the copolymer was lowered by incorporation of azidophenyl groups. The derivatized copolymer was then immobilized on a polystyrene matri x. The surface wettability of the immobilized polystyrene matrix chang ed with temperature, whereas that of untreated polystyrene matrix was insensitive to temperature. The measurement of contact angle showed th at the surface of the immobilized matrix was hydrophobic at 37 degrees C but hydrophilic at 10 degrees C. Micropatterned immobilization of t he copolymer on the polystyrene matrix surface was carried out using a photomask. The surface micropattern was clearly observed by phase-con trast microscopy at 37 degrees C. At low temperatures, hydration of gr aft chains erased the micropattern. The polystyrene matrix with microp atterned surface was applied to tissue engineering. Mouse fibroblast S TO cells grown on the surface area, on which thermosensitive polymers were immobilized, were selectively detached by lowering the temperatur e.