Krce Lucija, Šprung Matilda, Rončević Tomislav, Maravić Ana, Čikeš Čulić Vedrana, Blažeka Damjan, Krstulović Nikša, Aviani Ivica
Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia.
Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia.
Nanomaterials (Basel). 2020 May 29;10(6):1040. doi: 10.3390/nano10061040.
We aim to elucidate the mode of antibacterial action of the laser-synthesized silver colloid against . Membrane integrity was studied by flow cytometry, while the strain viability of the treated culture was determined by plating. The spectrofluorometry was used to obtain the time development of the reactive oxygen species (ROS) inside the nanoparticle-treated bacterial cells. An integrated atomic force and bright-field/fluorescence microscopy system enabled the study of the cell morphology, Young modulus, viability, and integrity before and during the treatment. Upon lethal treatment, not all bacterial cells were shown to be permeabilized and have mostly kept their morphology with an indication of cell lysis. Young modulus of untreated cells was shown to be distinctly bimodal, with randomly distributed softer parts, while treated cells exhibited exponential softening of the stiffer parts in time. Silver nanoparticles and bacteria have shown a masking effect on the raw fluorescence signal through absorbance and scattering. The contribution of cellular ROS in the total fluorescence signal was resolved and it was proven that the ROS level inside the lethally treated cells is not significant. It was found that the laser-synthesized silver nanoparticles mode of antibacterial action includes reduction of the cell's Young modulus in time and subsequently the cell leakage.
我们旨在阐明激光合成银胶体对……的抗菌作用模式。通过流式细胞术研究膜完整性，同时通过平板接种确定处理后培养物的菌株活力。使用荧光分光光度法来获取纳米颗粒处理的细菌细胞内活性氧（ROS）随时间的变化情况。一个集成的原子力和明场/荧光显微镜系统能够研究处理前和处理过程中细胞的形态、杨氏模量、活力和完整性。经过致死处理后，并非所有细菌细胞都显示出通透性增加，并且大多保持其形态，仅有细胞裂解的迹象。未处理细胞的杨氏模量显示出明显的双峰分布，较软部分随机分布，而处理后的细胞随着时间推移，较硬部分呈现指数级软化。银纳米颗粒和细菌通过吸收和散射对原始荧光信号产生了掩盖效应。分辨出了细胞内ROS在总荧光信号中的贡献，并且证明了经过致死处理的细胞内ROS水平并不显著。研究发现，激光合成银纳米颗粒的抗菌作用模式包括随着时间推移降低细胞的杨氏模量，随后导致细胞渗漏。
