Effect of aging time of sol on structure andin vitro calcium phosphate formation of sol-gel-derived titania films

Abstract

Titanium and its alloys have been used successfully in the manufacture of orthopedic and dental implants to replace damaged bone tissue. In this study, different sol-gel-derived TiO(2) coatings were produced on titanium substrates using different aging times (5, 10, 24, or 48 h) of the sol before dipping the coatings and varying numbers (one, three, or five) of coating layers. The influence of the aging time of the sol on the structure of the titania coatings with respect to in vitro bioactivity was investigated. The in vitro bioactivity tests were done in a simulated body fluid (SBF). The sol properties were monitored using a capillary viscometer and dynamic light scattering to determine the viscosity and particle size, respectively. The topography of the films was characterized using atomic force microscopy. The various sol aging times and numbers of layers produced differences in the topography of the titania films. For the coatings with one and three layers, the aging of the sols had an influence on the height of the peaks (lower with longer aging times) although the peak distance was about the same. The number of coating layers had a stronger influence. The distribution of the peak distances became narrower with an increasing number of coating layers. The coating with three layers (top coating prepared after 24 h of sol aging) and the coatings with five layers had a similar distribution of peak distances (15-50 nm), which was favorable for calcium phosphate formation. On these substrates, calcium phosphate formation started within 3-6 days of immersion in SBF. The aging time of the titania sol and the number of coating layers were found to have a strong influence on the surface topography in the nanometer scale of the titania films. The results indicate that the topography of the outermost surface is of importance for in vitro bioactivity.

Surface Engineering and Modification for Biomedical Applications

“…Substrate withdrawal speed, viscosity of precursor solution, viscous drag, gravitational force and liquid-vapor surface tension play a peculiar role in deciding the required coating thickness onto the substrate [40][41][42]. Dip coating involves dipping of sample in the precursor solution followed by constant speed linear withdrawal of sample to deposit thin coating.…”

Biocompatibility of sol–gel-derived titania–silica coated intramedullary NiTi nails

“…This also highlights the utility of thin ceramic coatings in implant applications where significant strain is applied to the implant. It is known that sol-gel-derived titania coatings attract calcium and phosphate from the body fluid and form bone-like calcium phosphate on the surface, thus promoting bone bonding [13,19,20]. In addition, sol-gel processing of a Ti alloy has been shown to promote increased attachment of osteoblasts and enhanced formation of mineralized matrix [21].…”

How Can Nanotechnology Help to Repair the Body? Advances in Cardiac, Skin, Bone, Cartilage and Nerve Tissue Regeneration

“…Titanium, as a biocompatible material, has been used to enhance implant incorporation in bone for dental, craniofacial, and orthopedic applications. Studies have demonstrated that nanoporous titanium dioxide (TiO 2 ) surface modification alters nanoscale topography improving soft tissue attachment on titanium implants surface [65,66]. For example, the uses of nanoporous TiO 2 surface-modified implants, in a human dental clinical study, showed that TiO 2 thin film increased adherence in early healing of the human oral mucosa and reduced marginal bone resorption [67].…”