Enhanced osteogenesis and bactericidal performance of additively manufactured MgO-and Cu-added CpTi for load-bearing implants

Abstract

The bio-inertness of titanium, which is the ultimate choice of metallic material for implant applications, causes delayed bone–tissue integration at the implant site and prevents expedited healing for the patient. This can result in a severe issue for patients with immunocompromised bone health as titanium does not offer inherent antimicrobial properties, and thus, infections at the implant site are another concern. Current strategies addressing the issues above include using cemented implants as a coating on Ti6Al4V bulk material for orthopedic applications. Roadblock arises with coating failure due to weak interfacial bond at the Ti–cement interface, which necessitates revision surgeries. In this study, we added osteogenic MgO and antibacterial Cu to commercially pure titanium (CpTi) and processed them using metal additive manufacturing. Mg, an essential trace element in the body, has been proven to enhance osseointegration in vivo. Cu has been popular for its bactericidal capabilities. With the addition of 1 wt.% of MgO to the CpTi matrix, we observed a four-fold increase in the mineralized bone formation at the bone–implant interface in vivo. The addition of 3 wt.% of Cu did not result in cytotoxicity, and adding Cu to CpTi-MgO chemical makeup yielded in vivo performance similar to that in CpTi-MgO. In in vitro bacterial studies with gram-positive Staphylococcus aureus, CpTi-MgO-Cu displayed an antibacterial efficacy of 81% at the end of 72 h of culture. Our findings highlight the synergistic benefits of CpTi-MgO-Cu, which exhibit superior early-stage osseointegration and antimicrobial capabilities.