Layer-by-layer electrodeposition of chitosan quaternary ammonium salt antibacterial composite coating loaded with gentamicin

Constructing bio-based antibacterial composite multilayer coatings with sustained drug release is important for reducing the infection risk of bone tissue repair. In this paper, a layer-by-layer aqueous electrodeposition method was applied to prepare a bio-based composite coating of chitosan, hyaluronic acid, and chitosan quaternary ammonium salt on the titanium surface. By pretreating with poly (acrylic acid), controlling the electrochemical deposition process, and post-treating with glutaraldehyde, a multi-layer composite coating with a smooth surface, good interface bonding with the titanium substrate, and a thickness more than ten microns was obtained. The composite coating was used as a drug-carrying system for gentamicin sulfate, which showed obvious antibacterial effects against Escherichia coli and Staphylococcus aureus . The bio-based composite coating with a sandwich structure loaded with antibiotics effectively inhibited the burst release of antibiotics, and the 14-day release rate is only 68.4 ± 2.1 %, achieving sustained release of the drug. The hydrophilic chitosan quaternary ammonium salt on the surface of the composite coating can effectively inhibit the early adhesion of bacteria, while the slow release of gentamicin sulfate in the interlayer can exert a long-lasting antibacterial effect. The preparation of bio-based antibacterial composite coatings using a layer-by-layer electrodeposition strategy has promising applications in titanium orthopedic implants.