Fabrication and characterization of strontium- and copper-doped bioactive glasses modified biodegradable MgO-PCL coated magnesium biomaterials

There has been a good deal of research on improving the corrosion behavior of magnesium (Mg) by polycaprolactone (PCL) coating, albeit with destroying bioactivity and hydrophilicity. The adhesion of a polymeric layer to the surface of the metal is also a knotty problem. On the other hand, the micro-arc oxidation (MAO) process is a new method that can create thin films with desirable adhesion to the surface of the implants although these films could hardly control the degradation of Mg. In this research, a multifunctional nanocomposite coating showing significant adhesion to the surface of the substrate has been fabricated that can enhance not only the corrosion but also the bioactivity of Mg-based biomaterials. It can also improve their biological, antibacterial, and osteogenesis properties. The fabrication process of this multifunctional composite coating with these desirable features can be broadly separated into three main stages beginning with synthesizing strontium (Sr) and copper (Cu) doped bioactive glass nanoparticles (BGNs), applying micro-arc oxidation (MAO) nanocomposite coating on the surface of pure Mg, and finally sealing the pores of MAO layer by PCL with BGNs containing Sr and Cu at concentrations of 5, 10, and 15 wt%. After this process, the corrosion resistance, bioactivity, antibacterial, and cytotoxicity of Mg-based samples were assessed. It was found that the addition of 10 wt% of BGNs in the MAO-PCL nanocomposite enhanced corrosion resistance (78,343.358 KΩ.Cm²), bioactivity, cellular viability and antibacterial property (99%) of Mg-based scaffolds, which can be widely used in bone tissue engineering.