Electrophoretic-deposited hydroxyapatite-copper nanocomposite as an antibacterial coating for biomedical applications

In this study, the preparation of hydroxyapatite–copper (HA-Cu) nanocomposite coatings is based on electrophoretic deposition (EPD) method and their bioactivity, antibacterial behavior, and cytotoxicity are assessed. The HA-Cu nanocomposite coatings with different amounts of Cu (1, 3 and 5 wt%) deposited on Ti6Al4V substrates. The surface morphology, composition, and microstructure of these coatings are characterized through scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). Adding Cu nanoparticles into HA increased particle size and made coatings porous due to agglomeration of nano-sized particles. The in vitro bioactivity of these coatings is assessed by SEM and inductively coupled plasma (ICP) in simulated body fluid (SBF) for 28 days. The results indicate that an increase of Cu to nanocomposite coating, decreases the bioactivity, while adhesive strength of nanocomposite is increased. Antibacterial tests of as-prepared HA-Cu nanocomposites and pure-HA are assessed against E. coli and S. aureus and results indicate that pure-HA did not exhibit any antibacterial activity, whereas the presence of Cu in HA resulted in a good activity against E. coli and S. aureus. In vitro biocompatibility tests, MTT, are run to assess the cytotoxicity of HA-Cu nanocomposite coatings with osteoblast-like MG63 cells. The obtained HA-Cu nanocomposite coatings except for the sample with 5 wt% Cu exhibited higher cytocompatibility compared to pure-HA up to 7 days. It is revealed here that HA-3 wt% Cu nanocomposite coated on Ti-6Al-4V substrate with more efficient antibacterial properties (HA-3 wt% Cu vs. HA-1 wt% Cu) and better cytocompatibility (HA-3 wt% Cu vs. HA-5 wt% Cu) compared to other specimens, has higher potential to be applied as a promising bone implant with antibacterial capability in the bone tissue engineering.