Preparation of a composite hydrogel of polyvinyl alcohol/chitosan fiber with anisotropic properties for sustained drug release

Abstract

AbstractHydrogel with anisotropic properties has promising potentials, while its fabrication is still challenging. In this work, chitosan fiber (CF) was designed to reinforce polyvinyl alcohol (PVA) hydrogel anisotropically. First, CF was pre‐treated in a weak acidic buffer to create rough surface as well as outward‐stretched chitosan chain end segments, and then mixed with PVA in solution. A PVA/CFs composite hydrogel was thereafter prepared by casting the mixture with a pushing force followed by freeze‐thawing cycles. The microstructure of the composite hydrogel was characterized by scanning electron microscopy, optical microscopy and Fourier transform infrared spectroscopy, and its mechanical properties at the directions parallel to and perpendicular to the casting force were measured. Our results indicate that the pre‐treated CF can reinforce the PVA hydrogel effectively, especially along the casting force direction. The tensile strength, breaking elongation and toughness of the composite hydrogel with only 0.2% CFs at the parallel direction reach 175%, 117% and 244% those of the PVA hydrogel, respectively. The anisotropic reinforcement effect has been understood by the orientating of CFs and the interfacial bonding between the CFs and the PVA matrix. Moreover, bovine serum albumin was released sustainably from the anisotropic hydrogel to indicate its potential application.