High-Performance Photopolymerized Poly(vinyl alcohol)/Silica Nanocomposite Hydrogels with Enhanced Cell Adhesion

Poly(vinyl alcohol) (PVA) hydrogels have been considered as promising implants for various soft tissue engineering applications because of their tissue-like viscoelasticity and biocompatibility. However, two critical barriers including lack of sufficient mechanical properties and non-tissue-adhesive characterization limit their application as tissue substitutes. Herein, PVA is methacrylated with ultralow degrees of substitution of methacryloyl groups to produce PVA-glycidyl methacrylate (GMA). Subsequently, the PVA-GMA/methacrylate-functionalized silica nanoparticle (MSi)-based nanocomposite hydrogels are developed via the photopolymerization approach. Interestingly, both PVA-GMA-based hydrogels and PVA-GMA/MSi-based nanocomposite hydrogels exhibit outstanding compressive properties, which cannot be damaged through compressive stress-strain tests in the allowable scope of a tensile tester. Moreover, PVA-GMA/MSi-based nanocomposite hydrogels demonstrate excellent tensile properties compared with neat PVA-GMA-based hydrogels, and 15-, 14-, and 24-fold increase in fracture stress, elastic modulus, and toughness, respectively, is achieved for the PVA-GMA/MSi-based hydrogels with 10 wt % of MSi. These remarkable enhancements can be ascribed to the amount of long and flexible polymer chains of PVA-GMA and the strong interactions between the MSi and PVA-GMA chains. More interestingly, exciting improvements in the cell adhesion can also be successfully achieved by the incorporation of MSi nanoparticles.