Egg white-derived nanocomposite microspheres for alveolar bone defects management

In this study, we developed a new class of nanocomposite microspheres comprising of Ca²⁺ crosslinked chicken egg white (EW) and Zn-doped mesoporous silica nanoparticles (Zn–SiO₂), targeting the challenging alveolar defect repair applications. We drew inspiration from the “Chinese century egg” preservation techniques to crosslink the EW protein using Ca²⁺ ions under alkali conditions and this has led to a novel alkali-ionic (ai) cross-linked EW network with enhanced mechanical stability. Molecular dynamic simulation was deployed to elucidate the protein crosslinking mechanisms within the microspheres. Zn-doped mesoporous silica nanoparticles (Zn–SiO₂) were introduced as degradable functional nanofillers. Results show that the unique Zn–SiO₂/ai-EW nanocomposite microspheres have enhanced mechanical strength, desirable degradation profile and biomineralization capabilities. In vitro and in vivo studies show that with the gradual released Ca²⁺ from the EW matrix can promote osteogenic differentiation; Si⁴⁺ and Zn²⁺ can modulate the immune microenvironment and enhanced angiogenesis. The promising results have demonstrated the strong potential of Zn–SiO₂/ai-EW composite microspheres for alveolar bone repair applications.