Unrestricted usage of antibiotics has accelerated the emergence of new strains of microorganisms with antimicrobial resistance (AMR) and the development of therapeutic technologies that do not rely only on antibiotics. Herein, mesoporous hollow Fe₃O₄ nanoparticles (MHFPs) were synthesized by a one-pot hydrothermal method, and the feasibility and possible mechanism of using alternating magnetic field (AMF) with MHFPs to kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were explored. The presence of the AMF (2.5 kW, 210 kHz) combined with the MHFPs resulted in a dramatic decrease in colony forming units (CFU) for E. coli and S. aureus in 25 min compared with the pure MHFPs at concentrations of 500, 800 and 1000 μg mL⁻¹. Macroscopic hyperthermia was proved not to be the sole reason for the phenomenon. Visible membrane damage was demonstrated by live/dead staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) assays. Besides, the permeability and integrity changes of the cell membrane were then quantitatively confirmed by measuring the relative electrical conductivity. In addition, bacterial biofilms were significantly dispersed in the presence of MHFPs and AMF. These results suggested that under the mediation of AMF, MHFPs can potentially serve as an efficient nonantibiotic therapeutic platform to disperse bacterial biofilms and inactivate bacteria by damaging the cell membrane of the bacteria.

中文翻译：

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中空空心Fe3O4纳米粒子在交变磁场中的抗菌和生物膜活性。

不受限制地使用抗生素加速了具有抗微生物耐药性（AMR）的新微生物菌株的出现，以及不仅仅依靠抗生素的治疗技术的发展。这里，介孔中空的Fe ₃ ö _4个纳米颗粒（MHFPs）用一釜水热法合成，以及使用与MHFPs交变磁场（AMF）杀死的可行性和可能的机制大肠杆菌（大肠杆菌）和金黄色葡萄球菌（金黄色葡萄球菌）进行了探讨。AMF（2.5 kW，210 kHz）与MHFP结合使用会导致大肠杆菌和大肠杆菌的菌落形成单位（CFU）急剧下降。与纯MHFP相比，金黄色葡萄球菌在25分钟内的浓度分别为500、800和1000μgmL ^-1。事实证明，宏观热疗并不是造成这种现象的唯一原因。通过活/死染色，扫描电子显微镜（SEM）和透射电子显微镜（TEM）分析证明可见的膜损伤。此外，然后通过测量相对电导率来定量确认细胞膜的渗透性和完整性变化。此外，在MHFP和AMF的存在下，细菌生物膜显着分散。这些结果表明，在AMF的介导下，MHFPs可以潜在地充当有效的非抗生素治疗平台，以分散细菌生物膜并通过破坏细菌的细胞膜来灭活细菌。