Reversible temperature-responsive and lectin-recognizing glycosylated block copolymers synthesized by RAFT polymerization

Reversible temperature-responsive and lectin-recognizing glycosylated block copolymers composed of polyacrylamide (PAAm) and poly(N-isopropylacrylamide) (PNIPAm) were synthesized by consecutive RAFT polymerization reactions. PAAm bearing maltose moieties was synthesized by RAFT polymerization with a trithiocarbonate derivative as a chain transfer agent for chain extension and with N-isopropylacrylamide to obtain block copolymers. The resulting glycosylated block copolymers were responsive to temperature at approximately 33 degrees C (lower critical solution temperature; LCST) and formed aggregates 100 nm in diameter in aqueous media above the LCST. The aggregates specifically interacted with lectin in aqueous media above the LCST, forming conjugates. When the temperature was decreased below the LCST, the conjugate dissociated into the aqueous medium. The conjugates of block copolymer and lectin were reversible in response to changes in temperature.