Redox-stimuli responsive micelles from DOX-encapsulating polycaprolactone-g-chitosan oligosaccharide

Abstract

Chitosan-based amphiphilic graft copolymers are commonly obtained by modification of chitosan backbones with synthetic polymers hampering both bioactivity and biodegradability. In this work, we report the preparation of a series of chitosan oligosaccharide-grafted copolymers (PCL-g-COs) from coupling reactions between azide-pendent polycaprolactones (PCL-N3) and reducing-end alkynyl-modified chitosan oligosaccharides (COs-alkynyl). The resulting PCL-g-COs self-organized in water into nanoscale micelles (Rh<20 nm) having a COs shell and a PCL core. Locking of the core-micelles structure employing a disulfide-containing bis-alkyne cross-linker resulted in the formation of nano-vehicles which can be degraded in response to physiological (redox) stimuli. This feature was advantageously exploited to preferentially release an anticancer drug, doxororubicin, in response to the intracellular glutathione level.

Keywords: Chitosan oligosaccharide; Copolymers; Drug delivery; Micelles; Polycaprolactone; Redox-stimuli responsive.