Polydopamine-Mediated\nAntimicrobial Lipopeptide Surface\nCoating for Medical Devices

Biofilm formation on medical implants such as catheters\nis a major\nissue which needs to be addressed as it leads to severe health care\nassociated infections. This study explored the design and synthesis\nof a polydopamine-lipopeptide based antimicrobial coating. The coating\nwas used to modify the surface of Ultrathane Catheters. The lipopeptide <b>SL1.15</b> with an <i>N</i>-terminal cysteine was covalently\nconjugated to the polydopamine modified catheters via a Michael addition\nreaction between the thiol moiety in the peptide and the aromatic\nring in the polydopamine layer. The immobilization of the peptide\non the polydopamine coated catheters was confirmed using water contact\nangle, X-ray photoelectron spectroscopy, atomic force microscopy,\nand scanning electron microscopy (SEM). The antimicrobial activity\nof the coated catheters investigated using drug resistant and clinical\nstrains of Gram-positive (MRSA and S. aureus) and Gram-negative (E. coli, A. baumannii, and P. aeruginosa) bacteria revealed that lipopeptide immobilization inhibited >90%\nbacterial adhesion to the catheter surface. Additionally, biofilm\nassays against MRSA and E. coli revealed\nthat the lipopeptide immobilized catheters inhibited >85% bacterial\ngrowth after 1 week incubation. Finally, the cytotoxicity profile\nof the catheters using the human dermal fibroblast, and the human\nembryonic kidney cell lines demonstrated that the polydopamine-lipopeptide\ncoating was not toxic after 72 h incubation.