A novel antibacterial modification treatment of titanium capable to improve osseointegration

ABSTRACT Background.Titanium and its alloy represent the commonly used material in orthopedic joint prosthetics and dental implantology fields due to their excellent mechanical properties and biocompatibility. Among the different causes of orthopaedic and dental implants failure, the event of infections still represents the most serious and devastating complication that may involve biomaterial devices. Purpose. The aim of the present work is to develop an innovative osteointegrative and antibacterial biomimetic coating and to perform the chemical-physical and in vitro biological characterization of the coating using SAOS-2 cell line. Among the objects we intend to study the antibacterial properties of the coating against both Gram-positive and Gram-negative bacteria strains. The treatment is developed using the Anodic Spark Deposition (ASD) electrochemical technique. Methods. The proposed antibacterial ASD treatment was obtained in an electrochemical solution containing silicon, calcium, phosphorous, sodium and silver nanoparticles. Surface morphology was characterized using SEM and laser profilometry. A qualitative analysis of the chemical composition of the coating was assessed by EDS. The adhesion properties of the coating to the titanium bulk were performed with a 3 points bending test. SAOS-2 osteoblastic cell line spreading and morphology were investigated using SEM and Phalloidin staining after 24h, 48h and 72h of cell culture on the different coating, while the viability was assessed using Alamar Blue assay after 1, 4 and 7 day of cell culture. The bacterial adhesion and the antibacterial properties were investigated after 3h and 24h of incubation with Streptococcus mutans, Streptococcus epidermidis and Escherichia Coli bacterial strains. Results. The proposed anodization treatment was capable to provide a chemical and morphological modified titanium oxide layer, adherent and characterized by micropourous morphology resulted enriched by calcium, silicon, phosphorous and silver. The preliminary biological characterization showed an optimal SAOS-2 cell adhesion and proliferation. A strong antibacterial effect against both Gram-positive and Gram-negative strain has been shown. Conclusions. Considering the results obtained in the present study, we believe that the novel biomimetic antibacterial treatment represents a promising treatment capable to enhance the osteointegration and contemporaneously confer antibacterial properties to titanium for dental and orthopaedic fields.