Graphene Oxide-Hydroxyapatite Nanocomposite Coatings and Extracellular Matrix Protein Interactions for Enhanced Osseointegration in Dental Implants.

Graphene oxide (GO) has been recognised to have a strong protein-binding ability attributed to its high surface area and oxygen functional groups (OFGs) but is plagued with dose-dependent cytotoxicity. In contrast, hydroxyapatite (HA) is highly biocompatible but has shown relatively weak protein-protein interactions on the molecular scale. The strategic merging of GO and HA into the GO-HA nanocomposite has the potential to synergistically and precisely facilitate bioactivity and biocompatibility across the implant-tissue interface. Molecular docking, pharmacophore modelling, and molecular dynamics simulations were used to explore the molecular interactions of GO, HA, and GO-HA nanocomposites with ECM proteins, including fibronectin (FN), collagen (COL), laminin (LAM), periostin (POSTN), vitronectin (VN), and osseointegration-related integrin receptors under physiological conditions. The GO-HA nanocomposites exhibited an enhanced number of hydrogen bonds and decreased residue-level fluctuations relative to GO or HA individually, indicating improved interfacial interaction stability at the protein-surface interface. Molecular dynamics simulation results indicated that ECM proteins in the presence of GO-HA showed better conformational stability, which might lead to favourable integrin-mediated adhesion. Preliminary in silico toxicity-related screening of the individual GO and HA model structures suggested differential safety alert patterns, with GO showing more cautionary alerts than HA. These outputs were interpreted qualitatively because the predictive tools used were primarily designed for small molecules rather than nanomaterials. Overall, these in silico results at the molecular scale revealed insights into the surface-biomolecule interactions of GO-HA, which may pertain to early events in osseointegration and can be used to create awareness for downstream in vitro and in vivo validation of dental implant coatings.