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

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.

Sulfated glycosaminoglycan-based block copolymer: preparation of biocompatible chondroitin sulfate-b-poly(lactic acid) micelles.

Despite a growing interest in amphiphilic polysaccharide-based diblock copolymers as functional polymeric drug delivery nanosystems, biologically relevant sulfated glycosaminoglycan systems were not yet investigated. Here, we report the synthesis and the self-assembly properties in water of chondroitin sulfate-b-poly(lactic acid) (CS-b-PLA(n)). The CS-b-PLA(n) were synthesized using click-grafting onto method implying reducing-end alkynation of low-molecular weight depolymerized CS (M(w) = 5000 g·mol(-1)) and azide-terminated functionalization of PLAn (M(w) = 6500 g·mol(-1) (n = 46) and M(w) = 1700 g·mol(-1) (n = 20)).

Aniline-catalyzed reductive amination as a powerful method for the preparation of reducing end-"clickable" chitooligosaccharides.

Functionalized oligosaccharides are useful intermediates to prepare products for biological research or for the development of advanced functional materials. Here, we report the unprecedented use of aniline as an efficient organocatalyst reaction with "clickable" (azide or alkyne) amine for the transimination-mediated reductive amination of a chitooligosaccharide. Moreover, we demonstrate that alkyne-bearing aniline constitutes an excellent tool for the easy derivatization of chitosan oligosaccharides.