Evaluation of the Antibacterial Activity of Ag- and Au-Nanoparticles Loaded TiO2 Nanotubes

Current research on the antibacterial properties of implant surfaces has focused on using titanium nanotubes (TNTs) with diameters of 100 and 200 nm, which simultaneously show the best antibacterial properties, poor osseointegration, and ability to immobilize proteins. Therefore, the research aimed to develop an implantable material based on titanium dioxide nanotubes with a diameter of 50 nm doped with silver (AgNPs) and gold nanoparticles (AuNPs), indicating good absorption and antibacterial properties. Moreover, metallic nanoparticles deposited by varying methods should maintain sphericity and lack of agglomeration. For this purpose, the surface charge, wettability, stability of nanoparticles, and antibacterial properties against Gram-positive and Gram-negative bacteria, i.e., Staphylococcus epidermidis, Streptococcus mutans, and Pseudomonas aeruginosa, were performed. Obtained results indicate a greater resistance to leaching of silver nanoparticles compared to gold nanoparticles. These results are reflected in microbiological studies, both into the time and the effectiveness of the implantable material's antibacterial activity. A greater antibacterial effect of AgNPs than AuNPs has been confirmed. Also, AgNPs inhibit the multiplication of Gram-negative bacteria to a greater extent than Gram-positive bacteria. It has been proven that the TNT platforms deposited with metal nanoparticles via the voltammetric method are more effective in deactivating microorganisms. Besides, the results have proven that smaller TNTs effectively reduce live bacteria as nanotubes with a diameter of 100 and 200 nm.