Stable and self-healable LbL coating with antibiofilm efficacy based on alkylated polyethyleneimine micelles

Effective solutions are necessary for biomaterial-associated infections caused by bacteria adhesion and subsequent biofilm formation on the surface of biomedical implants/devices. Current antibacterial coatings are usually vulnerable, and their bactericidal efficacy is impaired or even eliminated upon scratching or abrasion. Thus, self-healable coatings capable of repairing defects themselves are highly desirable. In this work, N-decyl polyethyleneimine (DPEI), a cationic amphiphilic polymer able to self-assemble into micelles in water to concentrate the density of cationic charge, exhibited enhanced antibacterial activity towards the Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa). A layer-by-layer (LbL) assembled coating was prepared using DPEI micelles and polyacrylic acid (PAA), which could reduce more than 90% bacterial adhesion and prevent biofilm formation. In addition, the DPEI/PAA LbL-assembled coating remained stable even with rinsing in physiological saline for up to three weeks owing to the strong interaction induced by its high charge. More importantly, this antibacterial DPEI/PAA LbL-assembled coating achieved self-healing quickly under wet conditions after being scratched, preventing bacteria from adhering to the damaged areas and forming a biofilm. Importantly, this coating avoids the use of antibiotics, which is less likely to cause drug-resistance. In addition, this coating is also biocompatible with mammalian cells (C2C12 mouse myoblast). All these excellent properties endow this self-healing DPEI/PAA LbL-assembled coating with promising prospects for biomedical application.