Enhanced osteogenesis on titanium implants by UVB photofunctionalization of hydrothermally grown TiO₂ coatings

Abstract

Even though Ti-based implants are the most used materials for hard tissue replacement, they may present lack of osseointegration on the long term, due to their inertness. Hydrothermal treatment (HT) is a useful technique for the synthesis of firmly attached, highly crystalline coatings made of anatase titanium dioxide (TiO 2 ), providing favorable nanoroughness and higher exposed surface area, as well as greater hydrophilicity, compared to the native amorphous oxide on pristine titanium. The hydrophilicity drops even more by photofunctionalization of the nanostructured TiO 2 -anatase coatings under UV light. Human mesenchymal stem cells exhibited a good response to the combination of the positive surface characteristics, especially in respect to the UVB pre-irradiation. The results showed that the cells were not harmed in terms of viability; even more, they were encouraged to differentiate in osteoblasts and to become osteogenically active, as confirmed by the calcium ion uptake and the formation of well-mineralized, bone-like nodule structures. In addition, the enrichment of hydroxyl groups on the HT-surfaces by UVB photofunctionalization accelerated the cell differentiation process and greatly improved the osteogenesis in comparison with the nonirradiated samples. The optimal surface characteristics of the HT-anatase coatings as well as the high potentiality of the photo-induced hydrophilicity, which was reached during a relatively short pre-irradiation time (5 h) with UVB light, can be correlated with better osseointegration ability in vivo; among the samples, the superior biological behavior of the roughest and most hydrophilic HT coating makes it a good candidate for further studies and applications.

Strontium‐incorporated titanium implant surface treated by hydrothermal reactions promotes early bone osseointegration in osteoporotic rabbits

“…Sr‐incorporated surfaces with such nanoparticle coatings indeed showed super‐hydrophilic properties in our study, which was in accordance with the above reports. It is believed that super‐hydrophilic surfaces would not only enhance cell attachment, spreading, settling and subsequent proliferation and differentiation in vitro (Lorenzetti et al, ; Ogawa et al, ) but also be good for early osseointegration with dental implants in vivo compared with hydrophobic surfaces (Hicklin et al, ; Minamikawa et al, ; Vasak et al, ).…”

The Influence of Surface Modification on Bacterial Adhesion to Titanium-Based Substrates

“…Moreover, the photocatalytic nature of the nanocrystalline anatase coatings improved the bioperformances of the titanium substrate upon photoinduction by UV light. The photoactivated surfaces reduced the adsorption of inflammation-promoter plasma proteins and increased the bioactivity and osteogenesis due to the positive interaction of human mesenchymal stem cells with the HT coatings …”

“…The photoactivated surfaces reduced the adsorption of inflammation-promoter plasma proteins 20 and increased the bioactivity and osteogenesis due to the positive interaction of human mesenchymal stem cells with the HT coatings. 21 An alternative approach introduces functionalities onto the Ti-based implant surfaces, which can reduce the biocontamination level, improve the ability to self-clean, or both. The photoinduced phenomena occurring on TiO 2 surfaces upon UV irradiation are currently under study by several research groups who have reported the potential bactericidal effect of titania coatings under UV light (photokilling).…”

Surface thermal oxidation on titanium implants to enhance osteogenic activity and in vivo osseointegration

“…This layer minimizes both metallic ion release from the implant to the surrounding tissues10 and adverse body reactions11, and it has been considered to be of great importance for successful osseointegration. The properties of this surface oxide layer can markedly influence the biocompatibility of titanium1213. Thus, various surface oxidation methods, such as electrochemical treatment (anodic oxidation), chemical (acid and alkali) treatment, plasma spray deposition, sol-gel formation, ion implantation, and thermal oxidation, have been employed to develop a functional implant surface by changing the surface properties of the native passive layer to improve osseointegration141516171819.…”