Abstract：
As-prepared mesoporous silicon nanoparticles, which were synthesized by electrochemical etching of crystalline silicon wafers followed by high-energy milling in water, were explored as a sonosensitizer in aqueous media under irradiation with low-intensity ultrasound at 0.88 MHz. Due to the mixed oxide-hydride coating of the nanoparticles\' surfaces, they showed both acceptable colloidal stability and sonosensitization of the acoustic cavitation. The latter was directly measured and quantified as a cavitation energy index, i.e., time integral of the magnitude of ultrasound subharmonics. The index turned out to be several times greater for nanoparticle suspensions as compared to pure water, and it depended nonmonotonically on nanoparticle concentration. In vitro tests with Lactobacillus casei revealed a dramatic drop of the bacterial viability and damage of the cells after ultrasonic irradiation with intensity of about 1 W/cm2 in the presence of nanoparticles, which themselves are almost non-toxic at the studied concentrations of about 1 mg/mL. The experimental results prove that nanoparticle-sensitized cavitation bubbles nearby bacteria can cause bacterial lysis and death. The sonosensitizing properties of freshly prepared mesoporous silicon nanoparticles are beneficial for their application in mild antibacterial therapy and treatment of liquid media.
摘要：
制备的介孔硅纳米颗粒，通过对晶体硅片进行电化学蚀刻，然后在水中进行高能研磨来合成，在0.88MHz的低强度超声辐照下，在水性介质中作为超声敏化剂进行了探索。由于纳米颗粒表面的混合氧化物-氢化物涂层，它们显示出可接受的胶体稳定性和声空化的声增敏作用。后者被直接测量和量化为空化能量指数，即，超声次谐波大小的时间积分。与纯水相比，纳米粒子悬浮液的指数要高几倍，它非单调地依赖于纳米粒子的浓度。用干酪乳杆菌进行的体外测试显示，在纳米颗粒存在下以约1W/cm2的强度进行超声辐照后，细菌活力和细胞损伤急剧下降。其本身在约1mg/mL的研究浓度下几乎是无毒的。实验结果证明，细菌附近的纳米颗粒敏化空化气泡可引起细菌裂解和死亡。新制备的介孔硅纳米颗粒的超声敏化特性有利于其在温和抗菌治疗和液体介质治疗中的应用。
