Antibacterial properties and biocompatibility of coated titanium substrates

LAURA E. VALENTI; LAURA BONNET; MAURICIO GALIANO; CARLA E. GIACOMELLI

Congreso; Reunión conjunta de sociedades de Biociencias 2017; 2017

Titanium and titanium alloys have excellent mechanical strength, good corrosion resistance and biocompatibility and they have been widely used for producing orthopedic implants. Osteointegration is a critical response to the long-term success of these implants. Focusing the attention on the surface of the biomaterials, a hydroxiapatite (HA) coating on the implant surface can improve a direct implant fixation to bone. Even when the interaction of biomaterials with living tissues is favored, the problems of bacterial infections persist. A possible solution involves the surface modification with an antibacterial coating which maintains good biocompatibility. Incorporating silver nanoparticles (Ag-NPs) into a HA coating is an effective method to impart simultaneously both properties to the surface of the biomaterial. The objective of this work is to evaluate the antibacterial properties and biocompatibility of Ti6Al4V coated with Ag-NP and HA. To prepare the coatings, a two steps strategy was optimized involving the electrodeposition of HA and the impregnation with Ag-NP. Coated Ti6Al4V substrates were characterized by spectroscopy and microscopy. For the antimicrobial activity assays, the substrates were incubated with a S. aureus culture and observed by confocal fluorescence spectroscopy, while the viable bacteria were quantified by serial dilution plates. The biocompatibility was evaluated directly, by culturing human osteosarcoma cells (U-2OS) on the coated substrates and indirectly, by studying the effect of the extract from the coated material on the cell culture. The cell viability was quantified by resazurin assay. HA/Ag-NP coating inhibits completely the bacterial adhesion and diminishes three logs units the number of viable planktonic bacteria with a minimum cytotoxic effect. Therefore, the HA/Ag-NP coating is very promising to develop more effective orthopedic implants exhibiting antibacterial properties without a detriment in the biocompatibility. Keywords: HA/Ag-NP coating, Ti6Al4V coated substrates, biomaterials.