Effects of Plasma Treatment on the Bioactivity of Alkali-Treated Ceria-Stabilised Zirconia/Alumina Nanocomposite (NANOZR)

Abstract

Zirconia ceramics such as ceria-stabilized zirconia/alumina nanocomposites (nano-ZR) are applied as implant materials due to their excellent mechanical properties. However, surface treatment is required to obtain sufficient biocompatibility. In the present study, we explored the material surface functionalization and assessed the initial adhesion of rat bone marrow mesenchymal stem cells, their osteogenic differentiation, and production of hard tissue, on plasma-treated alkali-modified nano-ZR. Superhydrophilicity was observed on the plasma-treated surface of alkali-treated nano-ZR along with hydroxide formation and reduced surface carbon. A decreased contact angle was also observed as nano-ZR attained an appropriate wettability index. Treated samples showed higher in vitro bovine serum albumin (BSA) adsorption, initial adhesion of bone marrow and endothelial vascular cells, high alkaline phosphatase activity, and increased expression of bone differentiation-related factors. Furthermore, the in vivo performance of treated nano-ZR was evaluated by implantation in the femur of male Sprague–Dawley rats. The results showed that the amount of bone formed after the plasma treatment of alkali-modified nano-ZR was higher than that of untreated nano-ZR. Thus, induction of superhydrophilicity in nano-ZR via atmospheric pressure plasma treatment affects bone marrow and vascular cell adhesion and promotes bone formation without altering other surface properties.

Effect of Plasma Treatment on Titanium Surface on the Tissue Surrounding Implant Material

“…The mechanism of atmospheric pressure plasma treatment is that this active oxygen decomposes hydrophobic organic substances adsorbed on the surface of the material and gives the surface of the material superhydrophilicity. In our previous reports, it was reported that applying atmospheric pressure plasma treatment using piezobrush to the titanium surface is useful at the in vitro level for improving the initial adhesion of RBMCs and the ability to induce hard tissue differentiation [41][42][43][44]. In this study, the effect of atmospheric pressure plasma treatment on titanium surfaces was investigated for evaluation in vivo.…”

“…Since the initial reaction of the implant surface contacting the bone tissue is thought to be involved in the subsequent osseointegration, this time we evaluated it for 4 weeks. Therefore, this study was conducted in two stages, 4 to 8 weeks after implantation [21,40,42,43]. It is clear from various studies that even at the in vivo level, the bone bond on the surface of the implant material that was imparted with hydrophilicity, was better than that on the surface of the untreated implant material.…”

“…In this study, 20 male SD rats (Shimizu Laboratory Supplies Co., Kyoto, Japan; age 8 weeks, weighing 160 ± 15 g) were used (the test group; 10 rats, the control group; 10 rats). In vivo analysis in this study was based on our previous study [21,24,42,43]. Animals were administered inhalation anesthesia, followed by intraperitoneal injection of anesthetics (1.5 mL/kg).…”

“…It was also clarified that this surface induces initial adhesion and differentiation induction of rat bone marrow cells (RBMCs) [41]. In addition, Takao et al, and Zeng et al, have already used this device and clarified the effect of plasma treatment on both titanium and NANOZR, which is expected to be used for patients with metal allergies [42,43]. However, for clinicians to use piezobrush with confidence, the effects of atmospheric pressure plasma treatment on the tissues surrounding the implant must be examined at the in vivo level.…”

Effects of Surface Modification on Adsorption Behavior of Cell and Protein on Titanium Surface by Using Quartz Crystal Microbalance System

“…Similarly, it was observed that both treatment processes resulted in enhanced ALP activity and calcium precipitation compared to the untreated Ti surface, where the plasma-treated samples showed the best performance. Our previous reports [ 53 , 54 , 55 ] showed that both methods result in Ti surfaces with high neonatal bone formation potential in vivo.…”