Bioactive hydroxyapatite/chitosan/poly(vinyl alcohol)/gentamicin composite coating electrodeposited on titanium

Abstract

Titanium (Ti) is an implant material widely used in orthopedics due to its high corrosion resistance (naturally forms a passive oxide layer) and good mechanical properties. Although Ti has certain ability to osseointegrate, the biocompatibility and bioactivity of Ti can be significantly improved by modifying its surface. In order to improve antibacterial properties a broad spectrum antibiotic gentamicin was loaded in a composite coating of hydroxyapatite (HAP) with natural polymers chitosan (CS) and poly(vinyl alcohol (PVA) and was deposited on Ti using electrophoretic deposition (EPD) technique. EPD was carried out at the constant voltage on pure titanium plates from an aqueous suspension. Deposited HAP/CS/PVA and HAP/CS/PVA/Gent coating were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM). The obtained results confirmed the formation of new composite coatings. Cytotoxicity against two types of cell lines (MRC-5 and L929) was investigated using trypan blue dye-exclusion test (DET) and MTT assay for assessing cell metabolic activity. The antibiotic loaded coating (HAP/CS/PVA/Gent) exhibited good antibacterial activity against Staphylococcus aureus and Escherichia coli, while preserving low cytotoxicity, indicating the high potential for biomedical applications. Excellent osteogenic properties, through the promotion of osteoblast differentiation were confirmed by ALP assay. Results were much more pronounced for HAP/CS/PVA/Gent coating. Therefore, HAP/CS/PVA/Gent coating can be considered as an excellent promising candidate for biomedical hard tissue implants.