Investigation of the Long-Term Degradation Behaviour of Binary Mesoporous Bioactive Glass Nanoparticles

Bioactive glass nanoparticles (BGNs) have attracted widespread attention in regenerative medicine owing to their excellent biocompatibility and tissue repair capacity. However, the ion release behaviour associated with the long-term degradation of BGNs doped with different functional elements remains unclear. Herein, binary silicate BGNs (BGN-Ca, BGN-Mg, BGN-Zn, BGN-Cu and BGN-Mn) were prepared, and their degradation behaviour in normal saline was systematically evaluated over a period of up to 150 days. The evolution of particle morphology and size, ion release and pH changes in solution was characterised in detail. The results showed that the degradation behaviours of BGNs doped with different elements differed markedly. BGN-Ca and BGN-Mg exhibited the fastest degradation rates characterised by rapid degradation accompanied by higher Si release, whereas BGN-Zn and BGN-Mn showed comparable total Si release but displayed ‘fast-then-slow’ and ‘slow-then-fast’ release patterns, respectively. Overall, the reactivity of metal ions can provide a preliminary prediction of early ion-exchange trends, but the actual degradation behaviour is also co-regulated by multiple factors, including doping content, crystalline structure and solubility. This study elucidates the intrinsic relationship among doped elements, structural state and degradation behaviour and provides an experimental support for the precise design and stability regulation of multicomponent functionalised BGNs.