Drug-Loaded Polycaprolactone/Fibroin/Polydopamine Composite Coating on an Anodized Titanium Surface with Calcium and Phosphorus Deposited Using Electrospray Technology

Abstract

Due to the low bioactivity of titanium implants, the extended bone integration process after implantation substantially heightens the risk of inflammation, a primary cause of implant failure. To mitigate inflammatory responses and enhance bone integration between the implant and bone tissue, based on prior research that applied calcium phosphate (CaP) on titanium surfaces, we employed electrospraying technology to develop a drug-loaded polycaprolactone/silk fibroin/polydopamine (PCL/SF/PDA) composite coating as the second layer on top of the calcium phosphate deposition. The surface morphologies of the CaP deposits and composite coatings were characterized by SEM. The SF/PDA gel significantly increased the adhesion of the coating, thereby enhancing its clinical application potential. All materials exhibited excellent biodegradability, and their superior biocompatibility was confirmed through cell assays. Following in vitro experiments, in vivo studies were conducted using a rat cranial defect model. Micro-CT results and staining demonstrated that CaP deposition significantly accelerated bone integration between the titanium substrate and bone, while the drug-loaded polymer coating notably improved the inflammatory environment at the defect site. These findings offer new insights into the development of titanium implants.