National University of Science and Technology "MISIS", Moscow 119049, Russia.
State Research Center for Applied Microbiology and Biotechnology, Obolensk 142279, Russia.
ACS Appl Bio Mater. 2024 Aug 19;7(8):5579-5596. doi: 10.1021/acsabm.4c00685. Epub 2024 Jul 16.
Zn-containing TiO-based coatings with Na, Ca, Si, and K additives were obtained by plasma electrolytic oxidation (PEO) of Ti in order to achieve an effective and broad bactericidal protection without compromising biocompatibility. A protocol has been developed for cleaning the coating surface from electrolyte residues, ensuring the preservation of the microstructure and composition of the surface layer. Using high-resolution transmission electron microscopy, three characteristic microstructural zones in the PEO-Zn coating are well documented: zone 1 with a TiO-based nanocrystalline structure, zone 2 with an amorphous structure, and zone 3 around pores with an amorphous-nanocrystalline structure. The excellent cytocompatibility of PEO-Zn samples was confirmed by three different methods: monitoring the proliferation of MC3T3-E1 cells, assessing the viability of sheep osteoblast cells using calcein-AM staining and fluorescence microscopy, and incubation with spheroids based on primary osteoblast cells and mouse embryonic fibroblast NIH3T3 cells. The PEO-Zn coatings absorb >60% of the incident light over the UV and Vis-NIR spectral ranges. After 24 h, the PEO-Zn coatings completely inactivate four types of strains: Gram-positive CSA154 and ATCC29213 and Gram-negative K261 and U20, and also prevent U20 and K261 biofilm formation. The superior antibacterial activity is associated with the synergistic effect of Zn ions in safe concentration and reactive oxygen species (ROS) generated in response to either UV irradiation or soft short-term X-ray irradiation. The X-ray irradiation-induced ROS formation by a PEO coating is reported for the first time. The enhanced bactericidal activity after X-ray irradiation compared to UV illumination is attributed to the more intense ROS generation in the first few hours. The results obtained significantly expand the possibilities of using PEO coatings on the surfaces of titanium implants.
含锌的 TiO2 基涂层通过等离子体电解氧化 (PEO) 在钛上获得，添加了 Na、Ca、Si 和 K 以实现有效且广泛的杀菌保护，而不会影响生物相容性。开发了一种从涂层表面去除电解质残留物的清洁方案，以确保保留表面层的微观结构和组成。使用高分辨率透射电子显微镜，详细记录了 PEO-Zn 涂层中的三个特征微观结构区域：区域 1 具有 TiO2 基纳米结构，区域 2 具有非晶结构，区域 3 围绕具有非晶-纳米结构的孔。三种不同的方法证实了 PEO-Zn 样品具有出色的细胞相容性：监测 MC3T3-E1 细胞的增殖、使用 calcein-AM 染色和荧光显微镜评估绵羊成骨细胞的活力，以及与基于原代成骨细胞和小鼠胚胎成纤维细胞 NIH3T3 细胞的球体孵育。PEO-Zn 涂层在 UV 和 Vis-NIR 光谱范围内吸收超过 60%的入射光。24 小时后，PEO-Zn 涂层完全灭活四种类型的菌株：革兰氏阳性 CSA154 和 ATCC29213 以及革兰氏阴性 K261 和 U20，还可以防止 U20 和 K261 生物膜形成。优异的抗菌活性与安全浓度下的 Zn 离子和响应 UV 照射或软短期 X 射线照射产生的活性氧 (ROS) 的协同作用有关。这是首次报道 PEO 涂层在 X 射线照射下产生 ROS。与 UV 光照相比，X 射线照射后杀菌活性增强归因于最初几个小时内 ROS 的生成更强烈。获得的结果大大扩展了钛植入物表面使用 PEO 涂层的可能性。
