Kumari Monika, Kashyap Hemant K
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Langmuir. 2023 Apr 18;39(15):5440-5453. doi: 10.1021/acs.langmuir.3c00118. Epub 2023 Apr 3.
The promising broad-spectrum antibacterial activity of two-dimensional molybdenum disulfide (2D MoS) has been widely recognized in the past decade. However, a comprehensive understanding of how the antibacterial pathways opted by the MoS nanosheets varies with change in lipid compositions of different bacterial strains is imperative to harness their full antibacterial potential and remains unexplored thus far. Herein, we present an atomistic molecular dynamics (MD) study to investigate the distinct modes of antibacterial action of MoS nanosheets against () under varying conditions. We observed that the freely dispersed nanosheets readily adhered to the bacterial membrane outer surface and opted for an unconventional surface directed "wrapping-trapping" mechanism at physiological temperature (i.e., 310 K). The adsorbed nanosheets mildly influenced the membrane structure by originating a compact packing of the lipid molecules present in its direct contact. Interestingly, these surface adsorbed nanosheets exhibited extensive phospholipid extraction to their surface, thereby inducing transmembrane water passage analogous to the cellular leakage, even at a slight increment of 20 K in the temperature. The strong van der Waals interactions between lipid fatty acyl tails and MoS basal planes were primarily responsible for this destructive phospholipid extraction. In addition, the MoS nanosheets bound to an imaginary substrate, controlling their vertical alignment, demonstrated a "nano-knives" action by spontaneously piercing inside the membrane core through their sharp corner, subsequently causing localized lipid ordering in their vicinity. The larger nanosheet produced a more profound deteriorating impact in all of the observed mechanisms. Keeping the existing knowledge about the bactericidal activity of 2D MoS in view, our study concludes that their antibacterial activity is strongly governed by the lipid composition of the bacterial membrane and can be intensified either by controlling the nanosheet vertical alignment or by moderately warming up the systems.
在过去十年中，二维二硫化钼（2D MoS）具有前景广阔的广谱抗菌活性已得到广泛认可。然而，要充分发挥其抗菌潜力，就必须全面了解MoS纳米片选择的抗菌途径如何随不同细菌菌株脂质组成的变化而变化，而这一点迄今为止仍未得到探索。在此，我们开展了一项原子分子动力学（MD）研究，以探究MoS纳米片在不同条件下对（）的不同抗菌作用模式。我们观察到，自由分散的纳米片很容易附着在细菌膜外表面，并在生理温度（即310 K）下选择了一种非常规的表面导向“包裹-捕获”机制。吸附的纳米片通过使直接接触的脂质分子紧密堆积，对膜结构产生轻微影响。有趣的是，这些表面吸附的纳米片在其表面表现出大量磷脂提取，从而即使在温度仅轻微升高20 K时，也能诱导类似于细胞渗漏的跨膜水通道。脂质脂肪酰基尾部与MoS基面之间强烈的范德华相互作用是这种破坏性磷脂提取的主要原因。此外，与假想底物结合以控制其垂直排列的MoS纳米片，通过其尖角自发刺入膜核心内部，表现出“纳米刀”作用，随后在其附近引起局部脂质有序化。在所有观察到的机制中，较大的纳米片产生的恶化影响更为显著。鉴于关于二维MoS杀菌活性的现有知识，我们的研究得出结论，其抗菌活性受细菌膜脂质组成的强烈影响，并且可以通过控制纳米片的垂直排列或适度加热系统来增强。
