Biocompatible and antibacterial properties of titania-Ag composite films on Ti

SANTILLÁN, MJ; QUARANTA, N; MEMBRIVES, F; AUDISIO, MC; GORUSTOVICH, A.A.; BOCCACCINI, AR

Valparaíso, Chile

Simposio; Solidos 2009; 2009

Universidad Técnica Federico Santa María

The use of titanium and its alloys in orthopaedic implants is based on the outstanding fracture strength and toughness of these materials [1]. However, the physiological medium is highly corrosive and may cause the degradation of metals and consequent release of unwanted products in the body [2]. The surface modification of metallic implants by ceramic or glass coatings is a strategy to achieve a better performance of those, favoring the implant-tissue joint. The use of titania (TiO2) in biomedical coatings has been widely studied for its biocompatibility. This ceramic material has good surface apatite forming ability when in contact with simulated body fluid (SBF), enhancing the bioactivity of materials employed in tissue engineering and orthopaedic prosthesis. Moreover, infection prevention is always an important topic during skin wound healing. Silver ions (Ag+) have been widely used as an antimicrobial agent in surface coatings [3]. Silver has also been incorporated into bioactive glass [4]. The antimicrobial activity of Ag mainly involves interactions with chemical groups of bacteria proteins [5]. In this research the fabrication of TiO2-Ag nanocomposite thick films on titanium substrates using electrophoretic deposition (EPD) is investigated. The Ag nanoparticles (nAg) were directly grown on the TiO2 nanoparticles surface by chemical reaction at low temperature. The biomedical coatings must be formed in specific cathodic EPD conditions in order to control the microstructure and characteristics of the films. The composite coatings were obtained by aqueous suspensions of TiO2-nAg nanocomposite and ethanol. Then, EPD coatings were sintered for 2 hr at 700 ºC in vacuum. The microstructure and composition of the composite coatings were analyzed and measured using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron dispersive scattering (EDS). The antibacterial activity of TiO2-nAg coatings was examined on Staphylococcus aureus in view of its significance for the pathogenesis of infections associated to orthopedic implants. The results obtained in this research showed that nAg are homogeneously formed on the TiO2 nanoparticles surface (inset of Fig.1) and the films of TiO2-nAg developed using EPD are homogeneous with smooth surface as it can be seen in the SEM image shown in Fig.1. These films present excellent biocompatibility and antibacterial property that enhance the bio-performance of the coatings. The characteristics mentioned above indicate that the composite material is a promising candidate to be used as antibacterial and bioactive coating on orthopaedic implants