Silane-coupled chitosan-cyclodextrin/rosmarinic acid-zinc complex coating improves the osseointegration of titanium implants in high-glucose environments

The osseointegration of titanium implants in a diabetic microenvironment is greatly limited by mitochondrial dysfunction, increased reactive oxygen species, and reduced osteoblastic activity. Rosmarinic acid (RA), a polyphenolic molecule with powerful antioxidant and anti-inflammatory properties, can chelate Zn ions to form the RA-Zn complex. This study aimed to develop a local drug delivery system on the titanium surface using this complex. Carboxymethyl-& beta;-cyclodextrin and chitosan were used to encapsulate the complex, and the coupling agent silane triethoxysilylpropyl succinic anhydride was used to covalently immobilize the chitosan molecules after binding to the alkali-heat treated titanium surface. A coating with good hydrophilic properties, adhesive strength, and frictional resistance, which allowed for the controlled and sustained release of RA-Zn, was successfully constructed. The coating had good biocompatibility and promoted the adhesion and proliferation of mouse preosteoblasts (MC3T3-E1) under high-glucose conditions. It upregulated the expression levels of osteogenic genes, increased the secretion of osteogenic-related proteins, and promoted cell mineralization. Furthermore, it improved the mitochondrial dynamics and restored mitochondrial dysfunction under highglucose conditions. This study proposes a new titanium implant surface modification strategy to deliver biological components with antioxidant and osteogenic activities to target sites.

Automated summary

This study aimed to improve the osseointegration of titanium implants in a diabetic microenvironment by developing a local drug delivery system using antioxidants and osteogenic substances. The researchers successfully constructed a coating with good biocompatibility and excellent performance, which promoted cell adhesion and proliferation and improved mitochondrial function.