Titanium implants functionalized with metal-polyphenol networks to enhance osseointegration in diabetic conditions.

The pathological microenvironment in diabetes mellitus (DM) patients is marked by local hyperglycemia, elevated oxidative stress, and increased susceptibility to infection, all of which commonly impair the osseointegration of titanium (Ti) implants. To address this clinical challenge, we developed a metal-polyphenol network (CGA/Sr coating) formed by chelating chlorogenic acid with strontium ions, which was anchored to the Ti surface via aminoethylaminopropyltrimethoxysilane (AEAPTMS). The CGA/Sr coating successfully suppressed the biological activity of S. aureus and E. coli, decreased the generation of reactive oxygen species (ROS), and enhanced mitochondrial function. Cell experiments have shown that the coating promotes the proliferation, differentiation and mineralization of osteoblasts, and up-regulates osteogenic markers (Runx2, OSX, OCN). This osteoinductive effect is mediated through the promotion of the Wnt/β-catenin pathway. The involvement of this pathway was further confirmed using a specific inhibitor (FH535). In a type 2 diabetic rat model, Ti rods coated with CGA/Sr exhibited enhanced osteogenesis and osseointegration, as confirmed by micro-CT scanning and histological evaluation. In conclusion, the CGA/Sr coating represents a promising biomaterial strategy for enhancing the osseointegration of Ti implants in DM patients.