Preparation of glycoside polymer micelles with antioxidant polyphenolic cores using alkylated poly(arbutin)s

Abstract

This paper describes the synthesis of long-chain-alkylated poly(arbutin)s (poly(Arb)-R_x, where R = alkyl-chain length and x = degree of substitution (DS)) and their aqueous micelle formation. DS was controlled by tailoring the alkyl reagent/main-chain phenol substituent feed ratio. The critical micelle concentrations (CMCs) of poly(Arb)-R_x were determined as 1.3–5.2 mg mL⁻¹ by the surface tension method. Introduction of longer alkyl substituents decreased CMC and also decreased aqueous solubility. In DLS measurement, the average micelle diameters were 225–616 nm, and micelle size decreased with increasing DS because of increased stabilization by hydrophobic alkyl substituents. Transmission electron microscopy indicated that mainly wormlike cylindrical micelles were formed, even with highly hydrophilic polymers. The alkylated polymer exhibited no cytotoxicity, and their antioxidant abilities were evaluated by the β-carotene bleaching method. Only 0.049 mol equivalents of poly(Arb)-C8₃₀ to linoleic acid was sufficient to preserve the β-carotene.