Construction of self-assembled polyelectrolyte complex hydrogel based on oppositely charged polysaccharides for sustained delivery of green tea polyphenols

Abstract

In this study, we have developed a novel polyelectrolyte complex (PEC) hydrogel that could be easily prepared by self-assembly of two food-grade polysaccharides salecan and N,N,N-trimethyl chitosan (TMC). The electrostatic interactions between two polysaccharides were driving force in complexation processes and have been demonstrated by FTIR, XRD, XPS and TGA. The swelling capacity, morphology and rheological property of the hydrogels could be well tuned by controlling salecan/TMC ratio. Green tea polyphenols (GTP) was efficiently encapsulated into PEC hydrogels and liberated in a sustained pattern. The amount of GTP released in simulated intestinal fluid (SIF) was significantly higher than simulated gastric fluid (SGF). Increasing salecan/TMC ratio also markedly enhanced GTP release amount. Release exponent n obtained in SGF indicated a Fickian diffusion, while in SIF an anomalous transport occurred. The release mechanism was well-fitted with Ritger-Peppas model. Taken together, these PEC hydrogels could be suitable carriers for intestinal targeted nutrient delivery.

Keywords: Food-grade polysaccharides; Green tea polyphenols; Polyelectrolyte complex hydrogel; Release mechanism; Self-assembly; Targeted nutrient delivery; pH-dependent release.