Work

A sodium phytate–ethyl cellulose coating with sustained oleoyl serine release enables spatiotemporal osteoimmune regulation of magnesium implants

Year: 2026

Type: article

Abstract: Biodegradable magnesium Mg implants hold immense potential in orthopedics , yet their rapid degradation , insufficient osseointegration , and immune imbalance remain major barriers to clinical translation . This study developed a sodium phytate SP passivation layer and an ethyl cellulose EC barrier loaded with oleoylserine OS multifunctional coating on Mg implant surfaces . This SP − EC − OS coating achieves spatiotemporal synergistic regulation through a triple mechanism of “ chemical passivation , barrier isolation , signal − controlled release . ” The SP layer enhances interfacial bonding strength and corrosion resistance , the EC layer provides a platform for controlled degradation and sustained release , while the continuous release of OS synergistically modulates cellular behavior with Mg 2 + . In vitro results demonstrated that the Mg − SP − EC − OS significantly enhancing corrosion resistance while its programmable release synchronizes with the bone regeneration cascade . More importantly , the synergistic effect of OS and Mg 2 + promotes osteoblast differentiation and mineralization , inhibits osteoclast activation , and induces macrophage polarization toward the M2 phenotype , achieving immune regulation − driven bone regeneration . In vivo validation of the femoral defect model in rats has shown that Mg − SP − EC − OS implants induce macrophage polarization toward the M2 phenotype through immune regulation , significantly promote new bone formation , reduce bone − implant interface cavities , and maintain excellent systemic biosafety . This multifunctional coating combines corrosion resistance , immunomodulation , and spatiotemporal osteogenic effects , achieving spatiotemporally controlled degradation aligned with the bone healing process . It provides a viable strategy for developing a new generation of degradable magnesium − based orthopedic implants .

Source: Journal of Controlled Release

DOI: 10.1016/j.jconrel.2026.114925