Jung Ara, Lee Hyungyu, Kim Heejin, Jeon Hyun Jeong, Park Sanghoo, Gweon Bomi
Department of Mechanical Engineering, Sejong University, Seoul, Republic of Korea.
Department of Biomedicine & Health Science, College of Medicine, The Catholic University, Seoul, Republic of Korea.
Sci Rep. 2024 Dec 30;14(1):31757. doi: 10.1038/s41598-024-82730-y.
Nonthermal plasma has been extensively utilized in various biomedical fields, including surface engineering of medical implants to enhance their biocompatibility and osseointegration. To ensure robustness and cost effectiveness for commercial viability, stable and effective plasma is required, which can be achieved by reducing gas pressure in a controlled volume. Here, we explored the impact of reduced gas pressure on plasma properties, surface characteristics of plasma-treated implants, and subsequent biological outcomes. Implant materials were treated with plasmas under varying discharge conditions, with pre-pumping times of 10 s and 20 s, thereby modulating the pressure during plasma treatments. Through optical emission spectroscopy, we demonstrated that the 5 Torr operational condition, achieved by 20-s pre-pumping, generated a greater density of excited nitrogen species and provided more stable plasma compared to the 16 Torr condition, achieved by 10-s pre-pumping. We then assessed the surface hydrophilicity, chemical composition, protein adsorption, and osteoblast activities on plasma-treated implants compared with those of untreated controls. Our results reveal that the 5 Torr condition significantly enhances removal of carbon-based impurities and increased protein adsorption, leading to improved cell adhesion, proliferation, and differentiation. In particular, implants treated under the 5 Torr condition showed significantly higher carbon-based impurity reduction and osteoblast differentiation performance compared to those treated under the 16 Torr condition. These findings suggest that optimizing gas pressure in plasma devices is critical for effectively controlling excited nitrogen radicals, which improves plasma surface modification and enhances the biocompatibility of implant surfaces.
非热等离子体已被广泛应用于各种生物医学领域，包括医疗植入物的表面工程，以提高其生物相容性和骨整合能力。为确保商业可行性所需的稳健性和成本效益，需要稳定且有效的等离子体，这可通过在可控体积内降低气压来实现。在此，我们探究了降低气压对等离子体特性、经等离子体处理的植入物表面特性以及后续生物学结果的影响。在不同放电条件下，对植入材料进行等离子体处理，预抽气时间分别为10秒和20秒，从而在等离子体处理过程中调节气压。通过发射光谱法，我们证明，与通过10秒预抽气达到的16托条件相比，通过20秒预抽气达到的5托操作条件产生了更高密度的激发态氮物种，并提供了更稳定的等离子体。然后，我们评估了经等离子体处理的植入物与未处理对照相比的表面亲水性、化学成分、蛋白质吸附和成骨细胞活性。我们的结果表明，5托条件显著增强了碳基杂质的去除并增加了蛋白质吸附，从而改善了细胞黏附、增殖和分化。特别是，与在16托条件下处理的植入物相比，在5托条件下处理的植入物显示出显著更高的碳基杂质减少和成骨细胞分化性能。这些发现表明，优化等离子体设备中的气压对于有效控制激发态氮自由基至关重要，这可改善等离子体表面改性并增强植入物表面的生物相容性。
