Hydroxyapatite/poly(vinyl alcohol)/chitosan coating with gentamicin for orthopedic implants

Abstract

Electrophoretic deposition (EPD) was employed to fabricate composite coatings aimed for orthopedic implants. Hydroxyapatite (HAP), poly(vinyl alcohol) (PVA) and chitosan (CS) coatings, with or without antibiotic gentamicin (Gent) were deposited in a single-step process from aqueous suspension, using EPD. Polymer/mineral composite coatings were formed with the aim to mimic the natural composition of bone tissue, along with improved coatings antibacterial properties, at the same time serving as a drug carrier, allowing local administration of antibiotic. Structural and morphological characterization of HAP/PVA/CS and HAP/PVA/CS/Gent coatings was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), and scanning electron microscopy (SEM) proving carbonate-substituted HAP. The presence of gentamicin contributed to the bactericidal activity of composite HAP/PVA/CS/Gent coating against Staphylococcus aureus and Escherichia coli. Cytotoxicity studies were performed towards human MRC-5 and mice L929 fibroblast cell lines, and both investigated samples (HAP/PVA/CS and HAP/PVA/CS/Gent) expressed good biocompatibility, without causing toxic effect on tested cells. Biomineralization potential was investigated by measuring the alkaline phosphatase activity, demonstrating high potential of HAP/PVA/CS/Gent to induce the growth of new HAP layer. Therefore, the present investigation proposes the production of composite coatings from non-toxic (aqueous) suspensions, consisting of biocompatible and bioactive components, along with antibiotic gentamicin, improving the antibacterial coatings' properties.