Gallium-modified chitosan/poly(acrylic acid) bilayer coatings forimproved titanium implant performances

A gallium-modified chitosan/poly(acrylic acid) bilayer was obtained by electrochemical techniques ontitanium to reduce orthopaedic and/or dental implants failure. The bilayer in vitro antibacterial propertiesand biocompatibility were evaluated against Escherichia coli and Pseudomonas aeruginosa and on MG63osteoblast-like cells, respectively. Gallium loading into the bilayer was carefully tuned by the electro-chemical deposition time to ensure the best balance between antibacterial activity and cytocompatibility.The 30 min deposition time was able to reduce in vitro the viable cell counts of E. coli and P. aeruginosa of2 and 3 log cfu/sheet, respectively. Our results evidenced that the developed antibacterial coating did notconsiderably alter the mechanical flexural properties of titanium substrates and, in addition, influencedpositively MG63 adhesion and proliferation. Therefore, the gallium-modified chitosan/poly(acrylic acid)bilayer can be exploited as a promising titanium coating to limit bacterial adhesion and proliferation,while maintaining osseointegrative potential.