Preparation and characterization of a novel amphiphilic nanocarrier based on enzymatic polymerization-derived α-1,3-glucan for efficient quercetin encapsulation

Biodegradable nanocarriers based on polysaccharide-derived amphiphilic copolymers are promising candidates to enhance drug solubility and stability. This study aimed to design a novel amphiphilic carrier based on enzymatic polymerization-derived exopolysaccharides, α-1,3-glucan. Glycosyltransferase I from Streptococcus mutans was used to synthesize α-1,3-glucan, and the amphiphilic α-1,3-glucan-graft-poly(ε-caprolactone) (Glucan-g-PCL) copolymer was synthesized via a homogeneous ring-opening polymerization (ROP) in ionic liquid, 1-butyl-3-methylimidazolium chloride. The chemical structures and physical properties of Glucan-g-PCL copolymer were characterized by FT-IR, 1H NMR, XRD, and TGA. The self-assembly behavior of the amphiphilic α-1,3-glucan derivative was investigated by fluorescence probe. The results showed that Glucan-g-PCL exhibited a low critical aggregation concentration (CAC) and formed core-shell structured nanostructure via self-assembly. Quercetin (Qu), a hydrophobic active component, was successfully encapsulated within the Glucan-g-PCL micelle-like nanostructure, showing efficient encapsulation and dispersion in water. Qu/Glucan-g-PCL micelle-like nanostructure (Qu/M) was characterized by DLS, TEM, FT-IR, and XRD. FT-IR and XRD analyses showed that Qu was present in an amorphous state in the formulation and without any chemical reactions during the sample preparation procedures. In addition, the antioxidant properties of the Qu/M were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, and significantly improved antioxidant activity was observed for Qu/M compared to Qu/water. The utilization of Glucan-g-PCL nanostructure encapsulation opens up new possibilities for enhancing and expanding the practical applications of quercetin and α-1,3-glucan.