Dual-Anchoring Intercalation Structure and Enhanced Bioactivity of Poly(vinyl alcohol)/Graphene Oxide-Hydroxyapatite Nanocomposite Hydrogels as Artificial Cartilage Replacement

Through the dual-anchoring effect, hydroxyapatite (HA) molecules were intercalated into graphene oxide (GO) layers to form a GO-PEG-HA hybrid, and PVA/GO-PEG-HA nanocomposite hydrogels were prepared. Compared with GO-HA enhanced hydrogen bonding formed for GO-PEG-HA hybrid, resulting in a higher intercalation ratio and interlayer spacing of GO and homogeneous distribution of HA particles on GO layers without aggregation. With increasing HA content, the pore size increased, and compressive deformation resistance and the lubrication property of hydrogel were improved. Mouse bone marrow mesenchymal stem cells (mBMSCs) with a spindle shape were distributed uniformly and directionally on the hydrogel, and introduction of HA significantly promoted cell proliferation and improved the cytocompatibility of the hydrogel by coating the sharp edge of GO sheets. When the hydrogel was dipped into simulated body fluid solution, the mass ratio of the hydrogel showed a remarkable rise, and a rough surface with deposited HA and HCA nanoparticles was observed, resulting from the osteoinductive deposition effect and mineralizing capability of the hydrogel. Such PVA hydrogels showed promising potential for cartilage replacement application.