Simple Preparation\nand Bone Regeneration Effects of\nPoly(vinyl alcohol)–Resveratrol Self-Cross-Linked Hydrogels

Hydrogels have broad\napplication prospects in bone repair. Pure\npoly(vinyl alcohol) (PVA) hydrogels have limited applications because\nof their low hardness and poor mechanical properties. This study found\nthat resveratrol (Res) and PVA self-assembled and cross-linked through\nthe formation of strong hydrogen bonds after freeze–thawing,\nforming an easily available PVA–Res supramolecular hydrogel\nthrough a green process. PVA–Res hydrogels with different Res\nwt %:10 wt % PVA ratios were prepared through freeze–thawing\nand designated as 0.4, 1.2, and 2.0 wt % PVA–Res hydrogels.\nRheological studies demonstrated that the viscoelastic modulus of\nthe PVA–Res hydrogels was significantly improved compared to\npure PVA hydrogels. The viscoelastic modulus <i>G</i>′\nof 1.2% PVA–Res hydrogel was 2299 Pa, which was 8.5-fold that\nof the pure PVA hydrogel. We conducted a study on cell proliferation\nand osteogenic differentiation using MC3T3-E1 (preosteoblasts from\nnewborn mouse calvaria). The results showed that the 0.4% PVA-Res\nhydrogel promotes alkaline phosphatase activity and mineral deposition.\nReal-time quantitative PCR (RT-qPCR) analysis demonstrated that the\n0.4% PVA–Res hydrogel upregulated the expression of osteogenic\ndifferentiation-related genes (BMP-9, OCN, and ALP). Furthermore,\nRT-qPCR and flow cytometry demonstrated that the 0.4% PVA–Res\nhydrogel could effectively promote the M2 transformation and polarization\nof mouse mononuclear macrophage leukemia cells (Raw 264.7). The expression\nof related genes, such as Arg-1 and CD206, significantly increased,\nwhereas that of M1 polarization-related genes, such as iNOS and TNF-α,\nsignificantly decreased. In summary, PVA–Res supramolecular\nhydrogels are potential materials for use in bone repair.