Department of Chemistry and Biochemistry , Queens College-City University of New York , Flushing , New York 11367 , United States.
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , PR China.
Anal Chem. 2018 Oct 16;90(20):12123-12130. doi: 10.1021/acs.analchem.8b03043. Epub 2018 Sep 27.
Fast and cost-efficient detection and identification of bacteria in food and water samples and biological fluids is an important challenge in bioanalytical chemistry. It was shown recently that bacteria can be detected by measuring the decrease in the diffusion current to the ultramicroelectrode caused by cell collisions with its surface. To add selectivity to the bacteria detection, herein we show the possibility of collision experiments with the signal produced by electrochemical activity of bacterial cells reducing (or oxidizing) redox species. The mediator oxidation/reduction rate can be used to identify different types of bacteria based on their specific redox activities. Here we report the analysis of electrochemical collision transients produced by two kinds of bacteria, Escherichia coli and Stenotrophomonas maltophilia. The effects of the charge and redox activity of bacterial cells on collision events are discussed. The current transients due to live cell collisions were compared to those produced by bacteria killed either by heavy metal ions (cobalt) or by an antibiotic (colistin). This approach is potentially useful for evaluating the effectiveness of antimicrobial agents. Finite-element simulations were carried out to model collision transients.
快速且经济高效地检测和鉴定食品和水样以及生物体液中的细菌是生物分析化学的一个重要挑战。最近有人表明，可以通过测量由于细胞与表面碰撞而导致的超微电极扩散电流的减小来检测细菌。为了为细菌检测增加选择性，本文展示了通过电化学活性的细菌细胞还原（或氧化）氧化还原物质产生的信号进行碰撞实验的可能性。根据其特定的氧化还原活性，可以使用介体氧化/还原速率来识别不同类型的细菌。本文报告了两种细菌（大肠杆菌和嗜麦芽寡养单胞菌）的电化学碰撞瞬变分析。讨论了细菌细胞的电荷和氧化还原活性对碰撞事件的影响。将活细胞碰撞产生的电流瞬变与通过重金属离子（钴）或抗生素（黏菌素）杀死的细菌产生的电流瞬变进行了比较。这种方法对于评估抗菌剂的有效性可能很有用。进行了有限元模拟以模拟碰撞瞬变。
