Sodium Alginate/Copper Sulfide Hybrid Coating with Anti-Adhesive and Photothermal Capabilities for Treating Bacterial Infection

The main cause of implant-associated infection (IAI) formation is biofilm formation. Bacterial adhesion serves as the first stage of biofilm formation, and the construction of antibacterial adhesion coatings is an important method to prevent biofilm formation. However, materials that resist bacterial adhesion do not themselves have antimicrobial properties. Meanwhile, the photothermal effect induced by near-infrared (NIR) has a very wide range of application scenarios in the antibacterial field. The high temperature of the coating causes the bacterial membrane to rupture and eventually die, without leading to bacterial drug resistance. It can be used as one of the treatment methods for IAI. Here, we successfully prepared a dual-functional coating on titanium sheets (Ti-CuS@SA) with sodium alginate (SA) as an antibacterial adhesion material and copper sulfide to provide a photothermal effect. First, the introduction of SA greatly reduced the number of E. coli and S. aureus adhesions. Under near-infrared light (NIR-II) irradiation, a small number of bacteria adhering to Ti-CuS@SA were killed, and further bacterial reproduction to form biofilm was effectively inhibited. Therefore, a dual-functional coating with polysaccharides as an anti-adhesion defense for implants coupled with a photothermal agent is an important strategy for the treatment of IAI.