Benzothiazole-disulfide based redox-responsive polymers: facile access to reversibly functionalizable polymeric coatings

Abstract

Selective modification of polymeric coatings with high fidelity is important for various biomedical applications. This is especially true if reversible functionalization is desired to achieve a conditional response. In the present study, we report on the synthesis of functional copolymers bearing activated disulfide groups as side chains that are amenable to reversible thiol-based functionalization. A methacrylic monomer carrying a redox-responsive benzothiazole-disulfide group was copolymerized with a hydrophilic polyethylene glycol (PEG) based monomer using reversible addition–fragmentation chain transfer (RAFT) polymerization. Functional copolymers with varying ratios of the benzothiazole disulfide-based methacrylate (BDSMA) monomer were obtained with high conversions and narrow molecular weight distributions. The obtained copolymers were demonstrated to undergo facile post-polymerization functionalization through the thiol–disulfide exchange reaction with model thiol-containing molecules. These polymers were employed in the fabrication of reactive surface coatings on glass, where functionalization using thiol-containing fluorescent dyes and cell-adhesive ligands was demonstrated. The reversibility of the reaction enabled the release of the conjugated molecules upon exposure to dithiothreitol (DTT). Redox-responsive disulfide conjugation of cell-adhesive peptides enabled attachment of cells on the surface, and their subsequent release under a reducing environment. Facile synthesis of these efficiently functionalizable disulfide-containing copolymers and their utilization to fabricate reversibly functionalizable coatings provide a versatile interface for various biomedical applications.