Polydopamine-functionalized nanohydroxyapatite coated exosomes with enhanced cytocompatibility and osteogenesis for bone regeneration

BackgroundMesenchymal stem cells-derived exosomes, crucial in regenerative medicine, have been explored for their potential for the functional modification of bone scaffolds.ObjectiveTo design a functionally modified biomimetic nanohydroxyapatite using exosomes and explore its effects on bone regeneration.MethodsA biomimetic nanohydroxyapatite (named as tHA) was fabricated as previous methods using a polydopamine (pDA) structure as a template, and exosomes (Exo) derived from periodontal ligament stem cells (PDLSCs) were used to functionally modify the tHA scaffold material through pDA. The effects of functional composite scaffold (tHA-Exo) on cells proliferation and osteogenic differentiation were investigated. Furthermore, their effect on bone regeneration was also evaluated in vivo.ResultsExosomes can be loaded onto the tHA via pDA and the tHA-Exo releases exosomes in a sustained and stable manner. tHA-Exo showed improved cytocompatibility compared to controls. Additionally, tHA-Exo significantly enhanced the proliferation and osteogenic differentiation of PDLSCs. More importantly, animal experiments have shown that tHA-Exo could dramatically promote bone regeneration.ConclusionThe tHA nanoparticles, functionally modified by the PDLSCs-Exo through pDA, significantly promoted bone regeneration by improving its cytocompatibility and osteogenic potential, which could serve as a promising material for promoting bone regeneration.