Synthesis of Drug/Dye-Incorporated PolymerProtein Hybrids

We present here a general methodology for significantly increasing the number of dye/drug molecules that can be attached per protein molecule. As a demonstration of this approach, poly(acrylic acid) (PAA)-based near-infrared fluorescence (NIRF) dye- and glucose-incorporated novel copolymers were synthesized, which were further employed for bioconjugation to avidin and bovine serum albumin (BSA). In this method, azide-terminated poly(tert -butyl acrylate) was synthesized via atom transfer radical polymerization (ATRP). Subsequent deprotection was performed to yield poly(acrylic acid) (PAA) possessing a reactive chain-end. A one-pot sequential amidation of the PAA with the amine derivatives of a near-infrared fluorescent dye (ADS832WS) and glucose produced NIRF dye-incorporated water-soluble copolymers. End-group modifications were performed to produce alkyne/biotin-terminated copo�lymers, which were further employed to generate dye-incorporated polymer–protein hybrids via the biotin–avidin interaction with avidin or by “click” bioconjugation with azide-modified BSA.