UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

Abstract

Background Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV) light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability. Methods and results Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light) were immersed in simulated body fluid (SBF) for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization. Conclusion UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite deposition may be a novel method to effectively enhance micro-roughened titanium surfaces without altering their microscale morphology.

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, ).…”

Osteoblast Attachment Compromised by High and Low Temperature of Titanium and Its Restoration by UV Photofunctionalization

“…Commercialized implant bodies are often roughened to enhance osseointegratio n [12,18,34,42,[69][70][71][72][73][74][75][76][77][78][79], where acid treatment is the most common surface treatment method [4,7,9,[80][81][82][83]. The surface-treated implant body is subsequently packaged dry or in solution (e.g., water or saline solution) before transportation and storage.…”

“…If there is a negative impact of temperature fluctuations, a potential countermeasure should be explored. Recent studies revealed that ultraviolet (UV) light treatment of titanium restored its superhydrophilicity after aging/storage [19,[31][32][33][34][35][36]. UV treatment has also been reported to remove surface impurities (e.g., hydrocarbons) [32,[37][38][39][40], thereby enhancing the biological activity of titanium for osteoblasts and bone [15,16,19,20,25,28,31,[33][34][35].…”

Decontamination of Ti Oxide Surfaces by Using Ultraviolet Light: Hg-Vapor vs. LED-Based Irradiation

“…Besides, UVA demonstrated a lower reduction in carbon content, lower hydrophilicity induction capacity and fewer antimicrobial effects than UVC [19,45,53,56]. Furthermore, most in-vitro and in-vivo studies that used Hg-vapor lamps in UVC photofunctionalization not only shown an increase in the osteoblastic activity in the early healing periods, but also a transformation in the wettability behavior from hydrophobic to superhydrophilic and antibacterial effects [45,[57][58][59][60][61]. Nevertheless, contrary to all the aforementioned papers, some research works do not observe significant effects of BIC and ISQ on photofunctionalized titanium dental implants after 9 months in minipigs [62].…”