Patent ID: 7052917

Claim:
A polymer compound which exhibits UCST (upper critical solution temperature) in an aqueous solution, the polymer compound comprising a polymerizable biotin derivative of formula (I) and acrylamide or methacrylamide as a copolymer component, in formula (I), R 2 represents a hydrogen atom or an alkyl group; R 3 and R 4 each independently represents a hydrogen atom, an alkyl group or an aryl group; T represents an oxygen atom or ═NH; W represents a single bond, a carbonyl group a thiocarbonyl group or a C 1-5 alkylene group; U represents a single bond or —NH—; X represents a single bond, a C 1-8 hydrocarbon bond, an oxygen atom or —NH—; Y represents a single bond, a carbonyl group, a thiocarbonyl group, —NH—, a 1,2-dioxyethylene group or a 1,2-diaminoethylene group; Z represents a single bond, a carbonyl group, a thiocarbonyl group, a C 1-5 alkylene group, an oxygen atom or —NH—; and V represents a single bond or a C 1-5 alkylene group, wherein the polymer compound has a weight-average molecular weight of about 500 to 1,000,000, and the molar ratio of acrylamide or methacrylamide to biotin is from 3 to 30.