Comparison between sol‐gel‐derived anatase‐ and rutile‐structured TiO₂ coatings in soft‐tissue environment

Abstract

The bioactivity of the surface reactive TiO(2) coatings for medical implants can be locally modified by CO(2) laser processing to match with the properties of surrounding tissues. The TiO(2) coatings heat-treated at 500 degrees C exhibit in vitro bioactivity. With further CO(2) laser treatment they exhibit enhanced in vitro bioactivity. The aim of this in vivo study was to compare the performance of heat-treated anatase-structured TiO(2) coatings with preheat-treated and CO(2) laser-treated rutile-structured coatings in terms of their ability to attach soft connective tissues. The coatings were characterized with TF-XRD and AFM. TiO(2)-coated discs were implanted in rats. The samples were analyzed with routine histology, SEM-EDS, and TEM. In both groups, already at 3 days, soft connective tissues were in immediate contact with the surface. No thick crystalline CaP layer was detected by SEM-EDS, but a thin amorphous CaP layer was detected by XPS. No gap between the cell membrane and the coating could be observed in TEM pictures. No differences were observed between the anatase- and rutile-structured coatings in terms of tissue responses. Further studies are needed to verify if the tissues are adherent to the surface of the implant.

Adhesion and proliferation of human fibroblasts on sol‐gel coated titania

“…The fact that sol‐gel‐derived TiO 2 ‐coating was retained with cells, but not without cells, during TEM processing further supports the firm fibroblast attachment. This is in line with our previous in vivo observations 10–13. The lack of abnormal features in the cultured cells suggests that fibroblasts do not react to titanium oxide as foreign material.…”

“…Biological fixation between implant surface and soft tissues could prevent microbial penetration and improve clinical performance of the implants 21. The sol‐gel treatment, described in this study and in our earlier investigations,10–13 provides a potential improvement to facilitate a direct integration with soft tissue.…”

“…Thus, the method facilitates the fabrication of coatings with varying bioactivities. TiO 2 coatings have been found to improve soft tissue attachment on cp titanium in vivo with almost absent capsule formation in soft tissue–titanium interface 10–13. The reason for good soft tissue response, lack of capsule formation, and increased connective tissue cell adhesion and spreading is apparently the smooth surface of coating with high‐energy negative surface charge and facilitated adsorption of proteins on sol‐gel‐derived titanium coatings,10, 13 but the actual mechanisms on cellular and molecular biological level are still poorly understood.…”

Electrochemical construction of a bio-inspired micro/nano-textured structure with cell-sized microhole arrays on biomedical titanium to enhance bioactivity

“…It is known that apatite nucleation and precipitation on a Ti surface via SBF immersion can be influenced by many factors, such as the crystalline structure [55], surface topography [4,56], surface wettability [57], surface charge [58] and oxide thickness [4]. Due to the abundant hydroxyl groups on the TiO 2 surfaces, the anodic Ti surface showed good hydrophilicity.…”

Formation of hydroxylapatite on CVD deposited titania layers

“…Due to high chemical stability in physiological environment [9] titania coatings deposited on orthopedic and dental implants improve their corrosion resistance. As has been shown [10][11][12], nanostructured TiO 2 may act also as a bioactive material inducing formation on its surface of hydroxylapatite (HA) Ca 10 (PO 4 ) 6 (OH) 2 -the basic mineral component of bone tissue. The presence of HA on an implant surface leads to additional bonding with the adjacent bone thus promoting the integration process.…”