Constructing epigallocatechin gallate/nano-ceria coating to enhance osteogenesis of titanium implants via alleviating oxidative stress

Excessive oxidative stress (OS) in the peri-implant environment is commonly considered to be an important reason for poor implant osseointegration, and numerous approaches have been developed for improving antioxidant capability of implants. However, it remains challenging to alleviate multiple OS factors in the peri-implant environment. Herein, we reported a facile and effective surface modification method to construct a mussel-inspired epigallocatechin gallate (EGCG)/nano-ceria coating with multiple antioxidant capacities on the titanium surface based on the combination of polyphenol–metal complexation and hydrothermal reaction, which consisted of antioxidative EGCG and CeO₂ nanoenzyme to mimic the multiple antioxidant mechanisms of living organisms. The effects of preparation conditions on the morphology, structure, multiple enzyme-like activities, and free radical scavenging ability of the coatings were investigated. The optimized EGCG/nano-ceria coating demonstrated good inhibition efficacy on multiple OS factors, non-toxicity, and improved osteogenetic activities with upregulated alkaline phosphatase expression and calcium deposition even under the simulated OS environment. The results indicated that EGCG/nano-ceria coating with multiple antioxidant capacities showed great potential for enhancing osteogenesis of titanium implants, and also suggested a promising bio-inspired surface modification strategy for improving the biological function of implant materials.