Surface modification of titanium implant for repairing/improving microenvironment of bone injury and promoting osseointegration

Bone injury and implantation operation are often accompanied by microenvironment damage of bone tissue, which seriously affects the process of osseointegration of implants, especially for titanium (Ti)-based bioinert materials. Thus, repairing or improving the microenvironment of damaged bone tissue is of great significance for bone rescue, reconstruction, and regeneration, which is still a major medical challenge. Oxidative stress (OS) and oxygen (O2) deficiency are considered to be specific physiological signals of the bone-injury microenvironment. From the above background, a coating consisting of manganese dioxide (MnO2) nanoenzyme and strontium (Sr) ions was fabricated on the surface of the Ti implant via a one-step hydrothermal treatment. MnO2 nanoenzyme presented in the coating alleviated OS and O2 deficiency at the injury site by catalyzing the decomposition of abundant endogenous H2O2 around the modified Ti implants into O2. In addition, Sr ions were released from the surface of the implant at a certain rate in a body-fluid environment, further promoting the adhesion, growth, and osteogenic differentiation of mesenchymal stem cells. More importantly, a Sprague Dawley rat femur model demonstrated that the modified Ti implant showed significant potential to accelerate bone tissue reconstruction in vivo. In summary, the present system provides a new idea for the treatment of bone injury and the development of new orthopedic implants.