Preparation of cerium-containing nanoporous titanium coatings for osseointegration and their promotion of osteogenic differentiation and anti-inflammatory properties

Conventional implants face many problems, such as failure to form good osseointegration and peri-implantitis in the early stage of implantation. It has been shown that hydroxyapatite (HA) has good osteoconductive ability. Also considering the potential of cerium oxide in osteogenesis and anti-inflammation, we prepared cerium-containing nanoporous HA coatings on the surface of pure titanium using the micro-arc oxidation (MAO) technique. The surface morphology of the coating was observed by scanning electron microscopy (SEM). The mechanical strength of the coating was examined by the ultrasonic oscillator. The elemental composition of the coating was examined by energy spectrum analysis (EDS). The ion release capacity of the cerium-containing coatings was examined by inductively coupled plasma emission spectrometry (ICP-OES). The hydrophilic properties of the coatings were examined by the hydrophilic angle test. In vitro, experiments were performed using rat bone marrow mesenchymal stem cells (BMSCs) and mouse mononuclear macrophages (Raw264.7). The biosafety of the cerium-containing coating was verified by live-dead staining and CCK-8 proliferation assay. The osteogenic and anti-inflammatory ability of the cerium-containing coating was examined by immunofluorescence staining and quantitative polymerase chain reaction (q-PCR). In addition, ion experiments were used to further demonstrate the osteogenic and anti-inflammatory potential of cerium ions. Subsequent animal experiments further demonstrated the osteoinductive potential of the cerium-containing HA coating. In conclusion, our cerium (HA)-containing coatings prepared by micro-arc oxidation on titanium surfaces show excellent osteogenic and anti-inflammatory properties, which are expected to improve the functionality of clinical implants and also lay the foundation for the clinical application of cerium ions.