Preparation and Characterization of PVA/PVP/CS Bionic Hydrogels

Poly(vinyl alcohol) (PVA) hydrogels are water-rich biomimetics with soft properties. However, the mechanical properties and surface properties of PVA hydrogels are quite different from natural oral soft tissues when applied to a simulated oral environment. To select suitable enhancement to modify PVA hydrogel for simulating oral soft tissue, an ingenious strategy is developed for enhancing PVA hydrogel in this study. The PVA/polyvinylpyrrolidone (PVP) (APV) hydrogel was prepared by solvent exchange and then cross-linked with chitosan (CS) to prepare a PVA/PVP/CS (PPC) composite hydrogel, and their surface, mechanical, lubrication properties, and biocompatibility were deeply investigated. The results demonstrate that the solvent exchanging system using DMSO promoted the cross-linking density of PVA and PVP. When the mass ratio of PVA/PVP was 3:1, the APV hydrogel had the excellent tensile property. After the cross-linking between APV and CS, the compression modulus of PPC hydrogels was 212% higher than that of PVA hydrogels and was closer to that of natural human tongue. The superhydrophilicity of APV was significantly adjusted by CS, and the water contact angle of PPC2 reached 27.07°. The lubrication properties of PPC were greatly improved compared with PVA and APV, and the average friction coefficient of the PPC2 hydrogel decreased by 62% compared with the APV hydrogel and could maintain stable lubrication properties under a simulating oral environment. The bionic PPC hydrogels had better biocompatibility than APV, and the survival rate of MC3T3-E1 cultured in PPC extract for 48 h reached 96.18%. This preparation strategy has greatly improved the comprehensive properties of PVA hydrogels without affecting their biocompatibility, which provides valuable insights into the enhancement of PVA-based hydrogels and the preparation of oral substitute bionic materials.