A photoresponsive fluorescent glycopolymer

Abstract

Herein we report a new photoresponsive amphiphilic glycopolymer, poly(pyrenylmethyl methacrylate)-b-poly(3-O-4-vinylbenzoyl-D-glucopyranose) (PPy-b-PBG), synthesized via atom transfer radical polymerization (ATRP). The aggregation behaviour of PPy-b-PBG was investigated in dilute aqueous solutions by dynamic light scattering and fluorescence spectroscopy. Formation of spherical aggregates was observed in solutions under controlled conditions due to the amphiphilic nature of the polymer. The presence of strong pyrene excimer emission in aqueous solution indicated the aggregation of pyrene units. Irradiation of these glycosomes with UV light resulted in the photo-solvolysis of 1-pyrenylmethyl esters accompanied by the disruption of the polymer aggregates due to the hydrophilic nature of the residual polymer. The morphology of the polymer aggregates before and after UV irradiation was examined by AFM, SEM and TEM. Encapsulation of hydrophobic Nile Red molecules by the glycosomes resulted in successful fluorescence modulation and UV irradiation resulted in the controlled release of the entrapped dye into water.