A new approach to replace antibiotics with natural pigment derivatives: Surface modification on the titanium implants

Bacterial infections associated with metal implants and devices are an urgent challenge in biomedical materials, especially when bacterial biofilms form on the implant surface. Here, we developed a novel strategy to combat infections with bacteria-associated titanium implants. Curcumin molecular modification was carried out on the phenolic hydroxyl group to obtain curcumin carboxylic acid (Cur-COOH) with the β-diketone structure of curcumin retained. Cur-COOH was covalently immobilized on the (3-aminopropyl) triethoxysilane (APTES)-treated titanium surface via an amidation reaction to establish the curcumin-titanium implant interface (Ti-g-Cur). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), water contact angle (WCA), and X-ray photoelectron spectroscopy (XPS) proved that Cur-COOH was successfully anchored on the titanium implants surface. Ti-g-Cur showed excellent antibacterial activity against E. coli and S. aureus, with antibacterial rates of 90.53 % and 94.38 %, respectively. Confocal laser scanning microscopy (CLSM) imaging showed that Ti-g-Cur could effectively inhibit bacterial biofilm formation for up to 5 days. In addition, Ti-g-Cur exhibited superior performance on mammalian hemocompatibility and cytocompatibility. Replacing antibiotics with natural pigment curcumin derivatives for application in biological materials can not only result in a high degree of biocompatibility but also fights bacteria and biofilm formation effectively.