In vitro and in vivo characterization of mineralized hydroxyapatite/polycaprolactone-graphene oxide based bioactive multifunctional coating on Ti alloy for bone implant applications

• Main Authors: Nagaraj Murugan, Chandran Murugan, Ashok K. Sundramoorthy
• Format: Article
• Language: English
• Published: Elsevier 2018-09-01
• Series: Arabian Journal of Chemistry
• Online Access: http://www.sciencedirect.com/science/article/pii/S1878535218300789

Hydroxyapatite (HAP) is a form of naturally occurring calcium apatite present in bone and tooth enamel. It is an important biomaterial with diverse biomedical applications such as a surface coating for metallic orthopedic implants. Synthesized pristine HAP has poor mechanical properties, inferior wear resistance and has limits for directly used in bone tissue engineering applications. To address these limitations, we synthesized a suitable orthopedic implant hybrid material (M-HAP/PCL/GO) by using positively charged calcium ions of mineralized HAP (M-HAP) combined with Polycaprolactone-negatively charged graphene oxide (PCL-GO). The successfully synthesized M-HAP/PCL/GO composite was comprehensively characterized by Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The micro-hardness technique was used to determine the mechanical strength of M-HAP (315 ± 4 Hv), M-HAP/GO (370 ± 3 Hv) and M-HAP/PCL/GO (455 ± 5 Hv). M-HAP/PCL/GO was also tested for its anti-bactericidal impact against Staphylococcus aureus and Escherichia coli. MG63 osteoblast cells cultured on the M-HAP/PCL/GO composite (10 mg/mL) coated sample, displayed outstanding viability after 3 and 5 days of incubation at pH 7.4, which indicated that the composite is suitable material for bone implants and induces the cell proliferation. It was also tested in vivo in Wistar rats and was observably beneficial bone formation within 28 days post-implant operation. These tests proved that the M-HAP/PCL/GO composite can be considered as a prospective candidate for future bone implant applications. Keywords: Polycaprolactone, Graphene oxide, Hydroxyapatite, Bone implants, Antibacterial activity, MG63 osteoblasts cells, Surface coating