School of Civil and Mechanical Engineering, Curtin University, Bentley, WA, 6102, Australia.
Department of Material Science and Engineering, Indian Institute of Technology, Kanpur, UP, 208016, India.
Sci Rep. 2024 Sep 2;14(1):20336. doi: 10.1038/s41598-024-67716-0.
Antimicrobial potential of bioactive glass (BAG) makes it promising for implant applications, specifically overcoming the toxicity concerns associated with traditional antibacterial nanoparticles. The 58S composition of BAG (with high Ca and absence of Na) has been known to exhibit excellent bioactivity and antibacterial behaviour, but the mechanisms behind have not been investigated in detail. In this pioneering study, we are using Atomic Force Microscopy (AFM) to gain insights into 58S BAG's adhesive interactions with planktonic cells of both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria; along with the impact of crystallinity on antibacterial properties. We have recorded greater bacterial inhibition by amorphous BAG compared to semi-crystalline glass-ceramics and stronger effect against gram-negative bacteria via conventional long-term antibacterial tests. AFM force distance curves has illustrated substantial bonding between bacteria and BAG within the initial one second (observed at a gap of 250 ms) of contact, with multiple binding events. Further, stronger adhesion of BAG with E.coli (~ 6 nN) compared to S. aureus (~ 3 nN) has been found which can be attributed to more adhesive nano-domains (size effect) distributed uniformly on E.coli surface. This study has revealed direct evidence of impact of contact time and 58S BAG's crystalline phase on bacterial adhesion and antimicrobial behaviour. Current study has successfully demonstrated the mode and mechanisms of initial bacterial adhesion with 58S BAG. The outcome can pave the way towards improving the designing of implant surfaces for a range of biomedical applications.
生物活性玻璃（BAG）的抗菌潜力使其在植入物应用中具有广阔的前景，特别是克服了传统抗菌纳米粒子的毒性问题。BAG 的 58S 成分（高钙且无钠）已被证明具有出色的生物活性和抗菌性能，但背后的机制尚未详细研究。在这项开创性的研究中，我们使用原子力显微镜（AFM）深入了解 58S BAG 与浮游菌（包括革兰氏阳性菌（金黄色葡萄球菌）和革兰氏阴性菌（大肠杆菌））的粘性相互作用；以及结晶度对抗菌性能的影响。我们记录到与半晶态玻璃陶瓷相比，无定形 BAG 对细菌的抑制作用更强，通过传统的长期抗菌测试，对革兰氏阴性菌的抑制作用更强。AFM 力距曲线说明了在接触的最初一秒内（在 250 毫秒的间隙处观察到），细菌与 BAG 之间存在大量结合，存在多次结合事件。此外，还发现 BAG 与大肠杆菌的粘附力（6 nN）比金黄色葡萄球菌（3 nN）更强，这可以归因于大肠杆菌表面均匀分布的更多粘附纳米域（尺寸效应）。本研究揭示了接触时间和 58S BAG 的结晶相对细菌粘附和抗菌行为的直接影响。目前的研究成功地证明了与 58S BAG 初始细菌粘附的模式和机制。研究结果可以为一系列生物医学应用的植入物表面设计提供改进的方法。
