The Biocompatibility and Antibacterial Properties of the CNTs-Doped Magnesium Based Composite Implants in a Long-Term Biodegradation Process

The aim of this paper is to increase a new biodegradable implant material’s biodegradability, biocompatibility, and osteoinductivity in the long-term degradation process, as well as its antibacterial properties, novel carbon nanotubes (CNTs) with or without Cu element were doped into calcium phosphate (CaP)–chitosan (CS) layers and then fabricated to obtain the magnesium (Mg) matrix composites. In this paper, we investigated the influences of the CNTs-CaP-CS/Mg composites on proliferation and osteogenic differentiation of human osteosarcoma cell (SaOS-2) and human bone marrow mesenchymal stem cells (hBMSCs). Furthermore, the Cu/CNTs-CaP-CS/Mg was prepared to improve the bioactivity and antibacterial activity of the composites. The results indicated that CNTs-CaP-CS/Mg composites were suitable for proliferation and differentiation of SaOS-2 cells. Stimulated by the CNTs-CaP-CS/Mg extracts, the ALP expression of hBMSCs increased in the first 16 days and the mineralization ability of hBMSCs was highly expressed throughout the whole process which might be through the Erk1/2 signaling pathway. After CNTs-loaded Cu element, the bioactivity of the coating was satisfactory. Moreover, this new implant exhibited excellent antibacterial properties for Escherichia coli (E. coli) and Staphylococcus albus (S. albus). Collectively, these data suggest that the CNTs-CaP-CS/Mg and Cu/CNTs-CaP-CS/Mg might be potentially applied as bone implants for future clinical use.