ドラッグデリバリーの空間的・時間的制御 刺激に応答する高分子材料とその時間および空間制御型ＤＤＳへの展開

Abstract

Poly(N-isopropylacrylamide) (PIPAAm) is well-known to change its structure in response to temperature in aqueous solutions. Polymer chains of IPAAm hydrate to form expanded structures in water at lower solution temperatures (<32°C). At temperatures above 32°C, however, the chains form compact structures by dehydration manifested as a lower critical solution temperature (LUST). Telomerization chemistry is expected to control oligomer molecular weight and create synthetic routes to semitelechelic oligomers averaging one functional end group per oligomer chain. Thiol compounds having functional groups as telogens are known to be effective in introducing functional groups to the ends of growing polymeric chains and regulating polymer molecular weight by radical telomerization via chain-transfer reactions. The research described in this paper is directed toward development and funda mental studies of biomedically relevant modulation systems using the temperature-responsive polymer, PIPAAm with a functional end group, as switching sequence. Temperature responsive semitelechelic PIPAAm polymer was attached to biomolecules, crosslinked hydrogels and solid surfaces to create new, modified bioconjugates, graft type gels and grafted surfaces, respectively.