Impact of Bulk Nanobubble Water on a TiO₂ Solid Surface: A Case Study for Medical Implants

In the field of medical implants, enhancing the wettability of artificial surfaces is crucial for improving biocompatibility. This study investigates the potential of ozone nanobubble water, an aqueous solution known for its strong oxidizing and sterilizing properties, to modify the surface of titanium dental implants. By immersing the implants in ozone nanobubble water for ∼10 min, we observed a significant transformation of their surface characteristics. Implant surfaces that had become hydrophobic over time, likely due to organic contaminants, became superhydrophilic, exhibiting a contact angle near zero. Fresh implant material is initially hydrophilic but becomes hydrophobic within a few days of drying. In sharp contrast, the hydrophilicity induced by ozone nanobubble water treatment persisted for more than one month. This durability suggests not only the removal of organic matter through cleaning but also a substantial alteration in the surface properties of the implants. The generation of ozone nanobubble water involved releasing ozone microbubbles into an aqueous solution containing trace amounts of iron and manganese, resulting in spherical particles with an average diameter of ∼10 nm. These particles could be bulk nanobubbles, a stabilized gas body surrounded by a solid shell composed of iron hydroxide. Termed "nanoshells" in our previous study, these particles demonstrated exceptional dispersibility without the need for stabilizing agents such as surfactants or capping agents, attributed to their inherent high wettability. The sustained hydrophilicity of the implant surfaces might be attributed to the adherence of these hydrophilic nanoshells to the implant's surface. This study highlights the potential of ozone nanobubble water for long-term surface modification of dental implants, offering a promising avenue for enhancing implant biocompatibility.