Antibacterial and anti-biofouling coating on hydroxyapatite surface based on peptide-modified tannic acid

Hydroxyapatite-based implant is widely used in the fields of artificial teeth and bones. However, the problem of microbial communities on hydroxyapatite surfaces remain a great challenge. In order to inhibit bacterial adhesion and activity in a long term, a salivary acquired pellicle (SAP) bioinspired tannic acid (SAP3-TA) is synthesized and characterized. The SAP inspired peptide sequence DDDEEK has a good adsorption performance on the surface of hydroxyapatite (HA). Tannic acid (TA) is a natural polyphenolic compound that can be extracted from green tea, and it has been proved to have an effective antibacterial property. After the coating of SAP3-TA on HA slices, the water contact angle is decreased to 14.2° and the HA surface becomes super-hydrophilic. The hydrophilic surface can prevent proteins adhesion and further inhibit the adhesion of bacteria. In this work, Streptococcus mutans (S. mutans) and bovine serum albumin (BSA) are used as models to prove the antibacterial and anti-biofouling properties of SAP3-TA coating on HA surface, respectively. SAP3-TA also shows low cytotoxicity to MG63 cells in the MTT test. All these results indicate that the SAP3-TA can be used as a potential antibacterial and anti-biofouling coating for hydroxyapatite-based implants.