Biocompatible Magnesium Implant Double-Coated with Dexamethasone-Loaded Black Phosphorus and Poly(lactide--glycolide).

Magnesium (Mg) and its alloys have presented a paradigm for biodegradability in the field of biomedical devices. However, biodegradation of Mg and its alloys cause the formation of hydrogen gas and basic molecules in the body. Here we developed a surface modification method for Mg implants by double-coating with osteogenic dexamethasone (Dex)-loaded black phosphorus (BP) and poly(lactide--glycolide) (PLGA). According to electrochemical and biodegradation tests, the prepared Mg-Dex/BP/PLGA showed remarkably enhanced resistance against corrosion possibly by the neutralization of basic molecules from Mg implants with acidic molecules from BP and PLGA with increasing biodegradation. Scanning electron microscopy, cell proliferation tests, Alizarin Red staining, and alkaline phosphatase activity tests confirmed that MC3T3-E1 cells significantly proliferated and were differentiated on the Mg-Dex/BP/PLGA surface. Taken together, the facile surface modification of Mg implants could be effectively harnessed for protecting the Mg surface from corrosion and inducing the osseointegration of preosteoblasts onto the Mg implant.