Electrophoretic Deposition of Gentamicin-Loaded ZnHNTs-Chitosan on Titanium

There is a need for titanium (Ti), an antimicrobial implant coating that provides sustained protection against bacterial infection. Chitosan (CS) coatings, combined with halloysite nanotubes (HNTs), are an attractive solution due to the inherent biocompatibility of halloysite, its ability to provide sustained drug release, and the antimicrobial properties of CS. In this study, the electrodeposition (EPD) method was used to coat titanium foil with CS blended with zinc-coated HNTs (ZnHNTs) and pre-loaded with the antibiotic gentamicin. The CS-ZnHNTs-gentamycin sulfate (GS) coatings were characterized using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and UV-visible spectroscopy. The coatings were further examined for their ability to sustain GS release, resist bacterial colonization and growth, and prevent biofilm formation. The CS-ZnHNTs-GS coatings were cytocompatible, exhibited significant antimicrobial properties, and supported pre-osteoblast cell proliferation. Hydroxyapatite also formed on the coatings after immersion in simulated body fluid. While the focus in this study was on zinc-coated HNTs doped into CS, our design offers tunability, as different metals can be coated onto the HNT surface and different drugs or growth factors loaded into the HNT lumen. Our results, and the potential for customization, suggest that these coatings have potential in the construction of an array of infection-resistant implant coatings.