Laser cladding with HA and functionally graded TiO2-HA precursors on Ti-6Al-4V alloy for enhancing bioactivity and cyto-compatibility

In the present study, the morphology and composition of Titanium alloy (Ti-6Al-4 V) surfaces were modified by laser cladding (LC) process to enhance the biocompatibility and bioactivity of orthopaedic implants. Ti-6Al-4 V substrates were processed using a pulsed Nd:YAG laser with various precursors: 100% HA and functionally graded TiO2-HA material (FGM). A set of laser parameters having 21.6 J/mm2 laser energy density or irradiance was applied for cladding, to execute a comparative study. The morphology, phases and wettability with different biological tests including bioactivity, protein adsorption, cell adhesion and cyto-compatibility were performed on cladded samples. The FGM cladding showed higher apatite precipitation than 100% HA cladding. Both LC samples had significantly higher amount of protein adsorption lead to higher cell adhesion and cyto-compatibility compared to non-cladded Ti-6Al-4 V alloy. In between the LC samples, FGM cladding had more protein adsorption and cell adhesion than 100% HA cladding. With six days of incubation, the proliferation rate of FGM cladding (215.6 ± 17.2%) was significantly higher than 100%HA cladding (134.6 ± 9.5%) and non-cladded Ti-6Al-4 V control (100%). All these outcomes reveal that the LC process improves the biocompatibility and bioactivity of Ti-6Al-4 V.