Two-Dimensional Materials/Biopolymer-Based Antimicrobial Coatings to Thwart Biofilm Formation on Medical Implants

Abstract

Infections associated with medical implants due to bacterial adhesion and biofilm formation are a serious problem, leading to acute health risks to patients by compromising their immune system. Therefore, suppressing biofilm formation on biomedical implants is a challenging task, especially for overcoming the drug resistance of bacterial biofilms. Herein, a synergistic efficient surface coating method was developed to inhibit biofilm formation on a model medical implant by combining the antimicrobial property of trimethyl chitosan (TMC) with either 2D material graphene oxide (GO) or black phosphorus (BP) sheets using layer-by-layer (LbL) self-assembly. The multilayer coatings of TMC/GO and TMC/BP were optimized on the glass surface (a model implant) and characterized by using spectroscopic and microscopy techniques. Next, we investigated the antibiofilm formation properties of the TMC/GO and TMC/BP coatings on glass surfaces against both Gram-negative, Escherichia coli (E. coli), and Gram-positive, Bacillus subtilis (B. subtilis), bacteria. The antibiofilm formation was studied using crystal violet (CV) and live/dead assays. Both the live/dead and the CV assays confirmed that the TMC/2D material (2DM)-coated surfaces prevented biofilm formation much more effectively compared to the uncoated surfaces. Scanning electron microscopy analyses revealed that the bacteria were affected physically by incubating with TMC/2DM-coated surfaces due to membrane perturbation, thereby preventing cell attachment and biofilm formation. Further, BP composite coatings (TMC/BP) showed a much better ability to thwart biofilm formation than GO composite coatings (TMC/GO). Also, multilayer coatings showed superior cytocompatibility with human foreskin fibroblast (HFF). Our results demonstrate that the developed coatings TMC/2DMs could be potential candidates for thwarting biofilm formation on medical implants.

Keywords: 2D materials; Medical implants; antimicrobials; biofilms; black phosphorus; chitosan; graphene oxide.