Biodegradable Glycopolymeric Micelles Obtained by RAFT-controlled Radical Ring-Opening Polymerization

The design and synthesis of an entirely degradable glycopolymer micelle was presented. This design relies on the utilization of RAFT -controlled radical ring-opening polymerization (rROP) technique to afford multiple insertions of cleavable ester linkages onto the backbone of the corona. RAFT polymerization using a macroRAFT agent based on poly(e-caprolactone) PCL was employed to control the polymerization of well-defined statistical glycopolymers of 1-0-acryloy1-2,3:4,5-di-Oisopropylidene-beta-n-fructop-yranose (1-O-AiPrFru) and 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) monomer. Three block copolymers were synthesized to generate poly(e-caprolactone)-b-poly[(1-0-acryloy1-2,3:4,5-di-O-isopropylidene-P-D-fructopyranose)-co-(5,6-benzo-2-methylene-1,3-dioxepane)] (PCL-b-P[(1-O-AiPrFru)-co-(BMDO)]) with varying block lengths. Self assembly of the deprotected block copolymers generated nonspherical egg shaped micelles, where the shorter chains PCL106-bP [(1-0-AFru)(69)-co-(BMDO)(9)] underwent self -assembly forming micelles with the hydrodynamic diameter (D-H) of 106 nm. The biodegradation of these micelles were investigated via enzymatic degradation by Lipase Pseudomonas sp., indicating entirely degradable architectures, which are no longer visible via dynamic light scattering (DLS). SEC further confirmed the appearance of fragmented glycopolymeric units. In vitro cell proliferation assay of the micelles and their degradation products revealed no toxicity against healthy human fibroblast HS27 and breast cancer MDA-MB-231 cell lines. The polymer concentration range tested was up to 0.20 mg.mL(-1) with the cell viabilities of >95%.