Synthesis and characterization of novel self-assembled amphiphilic α-1,3-glucan nanomicelles for drug delivery

Polysaccharide-based amphiphilic copolymers self-assemble in water to form micelle-like structures. They are expected to be used as nanocarriers in the biomedical field owing to their biocompatibility, biodegradability, and low toxicity. α-1,3-Glucan is a water-insoluble glucose homopolymer that can be generated through environmentally friendly enzymatic polymerization and easily purified without using organic solvents. Thus, it has attracted attention as a new bio-based material. In this study, we developed new nanomicelles based on α-1,3-glucan. Glycosyltransferase I from Streptococcus mutans was used to synthesize α-1,3-glucan, and a series of amphiphilic α-1,3-glucan-based graft copolymers (α-1,3-glucan-g-PLA) were synthesized with different L-Lactide supply ratios in the ionic liquid BmimCl. The results of FT-IR, 1H NMR, 13C NMR, XRD, and TGA verified that the reaction proceeded successfully. These amphiphilic α-1,3-glucan derivatives with low critical micelle concentrations can self-assemble to form core–shell structural micelles of various sizes (approximately 57–125 nm) in water. Furthermore, the self-assembled micelles were investigated as drug carriers using prednisone acetate (PA) as a model drug, and their sustained drug release behavior for 9 days was confirmed. These results revealed that the synthesized self-assembled micelles have promising potential as new carriers for the efficient delivery of hydrophobic drugs.