Síntese, caracterização e avaliação da atividade antibacteriana de vidros bioativos obtidos por sol-gel no sistema Si:Ca:P, dopados com prata e triclosan

Abstract

Infections associated with biomaterial implants are one of the principal causes of surgical revision. The chemical nature of biomaterials and the interaction with the organism’s defences favour bacterial colonization and the creation of biofilms which are resistant to antibiotic treatment. The creation of biomaterials resilient to infections has become a goal of the tissue engineering, a multidisciplinary science that goal the repair of damaged tissues and organic functions. Among the new biomaterials being studied, bioceramics stand out due to their excellent physico-chemical and biological properties. In the face of the necessity of creating biomaterials resilient to infection, we synthetized a new bioactive glass in powder form by the sol-gel route, 60Si:36Ca:4P system, stabilized by heat treatment at 600oC during four hours, and doped with various concentrations of silver and triclosan. Physico-chemical characterization was carried out with Scanning Electron Microscopy, Energy-dispersive X-ray Spectroscopy, Thermogravimetry, X-Ray Diffraction, and Infrared spectroscopy with Fourier Transform. The incorporation of increasing quantities of silver resulted in progressive desinfication and organization of the glass matrix of the compounds. Bioactivity was demonstrated by the formation of apatite after immersion for seven days in simulated body fluid (SBF). Antibacterial activity, demonstrated by means of a modificated microbiological procedure, was found to be proportional to the concentration of silver in the compound. The temporal dynamics of antimicrobial agent liberation into the SBF suggest a relationship with the ion exchange chemical reactions of the bioactivity. Absorption of triclosan to the surface of the bioactive glass was demonstrated when using bioactive glass silver doped. The antibacterial activity of final compound was found to be more intense that its isolated components, with excellent activity against the Escherichia coli ATCC25922 strain and another 36 bacterial strains isolated from infections of hospitalized patients. The compound VB-Ag3%-triclosan has characteristics that make it an excellent candidate for use in medical and orthodontic implants, after additional tests in vivo to ensure its safe use.