TEM Studies on Antibacterial Mechanisms of Black Phosphorous Nanosheets
TEM Studies on Antibacterial Mechanisms of Black Phosphorous Nanosheets
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DOI：
10.2147/ijn.s237816
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发表时间：
2020-01-01
影响因子：
8
通讯作者：
Shokuhfar, Tolou
中科院分区：
文献类型：
--
作者：
Phakatkar, Abhijit H.;Firlar, Emre;Shokuhfar, Tolou
目的：最近，二维（2D）纳米材料作为新型抗菌平台正在获得极大的关注，以对抗不断变化的抗菌剂耐药性水平。在2D纳米材料家族中，黑磷（BP）纳米片已被证明具有生物医学应用的潜力。然而，有必要获得纳米级的BP纳米片的抗菌活性的见解，这是在技术challenges.Methods的中心：超大BP纳米片的合成通过液体剥离法在环保脱氧水中。采用TEM、AFM和拉曼光谱技术对合成的BP纳米片进行了表征，并通过EDS和EELS元素分析对其化学稳定性进行了评价。通过超微切片机TEM技术在纳米尺度上评价BP纳米片的抗菌活性。此外，利用受损细菌的HAADF-STEM图像和EDS元素线图来分析诊断离子的存在。进行了支持性的SEM和ATR-FTIR研究以证实细菌细胞壁的损伤。采用体外菌落计数法对纳米片的抗菌性能进行了评价。结果：纳米片在脱氧水中的元素EELS和EDS分析证实了纳米片中没有氧峰。TEM研究表明，细菌细胞损伤的各种事件与失去细胞代谢和结构完整性。菌落计数试验结果表明，合成的BP纳米片（100 μ g/mL）在12 h内可杀灭95%的细菌。大肠杆菌膜损伤和结构完整性的丧失。这些事件包括BP纳米片与细菌细胞壁的相互作用、细胞质渗漏、细胞质从细胞膜脱离、脂质双层密度降低和聚集的DNA结构。受损细菌的EDS元素线图谱证实了细胞膜渗透性被破坏和细胞代谢丧失。SEM显微照片和ATR-FTIR支持性结果证实了细菌细胞壁损伤。
Purpose: Recently, two-dimensional (2D) nanomaterials are gaining tremendous attention as novel antibacterial platforms to combat against continuously evolving antimicrobial resistance levels. Among the family of 2D nanomaterials, black phosphorus (BP) nanosheets have demonstrated promising potential for biomedical applications. However, there is a need to gain nanoscale insights of the antibacterial activity of BP nanosheets which lies at the center of technical challenges.Methods: Ultra-large BP nanosheets were synthesized by liquid-exfoliation method in the eco-friendly deoxygenated water. Synthesized BP nanosheets were characterized by TEM, AFM, and Raman spectroscopy techniques and their chemical stability was evaluated by EDS and EELS elemental analysis. The antibacterial activity of BP nanosheets was evaluated at nanoscale by the ultramicrotome TEM technique. Further, HAADF-STEM image and EDS elemental line map of the damaged bacterium were utilized to analyze the presence of diagnostic ions. Supportive SEM and ATR-FTIR studies were carried out to confirm the bacterial cell wall damage. In vitro colony counting method was utilized to evaluate the antibacterial performance of ultra-large BP nanosheets.Results: Elemental EELS and EDS analysis of BP nanosheets stored in deoxygenated water confirmed the absence of oxygen peak. TEM studies indicate the various events of bacterial cell damage with the lost cellular metabolism and structural integrity. Colony counting test results show that as-synthesized BP nanosheets (100 mu g/mL) can kill similar to 95% bacteria within 12 hours.Conclusion: TEM studies demonstrate the various events of E. coli membrane damage and the loss of structural integrity. These events include the BP nanosheets interaction with the bacterial cell wall, cytoplasmic leakage, detachment of cytoplasm from the cell membrane, reduced density of lipid bilayer and agglomerated DNA structure. The EDS elemental line mapping of the damaged bacterium confirms the disrupted cell membrane permeability and the lost cellular metabolism. SEM micrographs and ATR-FTIR supportive results confirm the bacterial cell wall damage.