World Class University (WCU) program of Chemical Convergence for Energy & Environment (C2E2), School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), 599 Gwanak-ro, Gwanak-gu, Seoul 151-744, Republic of Korea.
Water Res. 2011 Oct 1;45(15):4615-22. doi: 10.1016/j.watres.2011.06.010. Epub 2011 Jun 24.
Development of an effective strategy for biofilm control in water-related system has become a matter of significant concern nowadays. Electrochemical monitoring, especially electrochemical impedance spectroscopy (EIS), is one of the efficient approaches to dealing with biofilm-related issues. However, currently used EIS methods without a redox probe intend to detect all effects generated from media components, bacteria, and bacterial metabolites, which used to make the signals from the attached bacteria and biofilm weakened. In this study, we tried improved EIS measurement to monitor bacterial adhesion and biofilm maturation using a double-layer capacitance. In this improved method, we minimized background signal by subtracting the interference of electrolyte caused by bacterial metabolism. Pseudomonas aeruginosa PA14 wild type and wspF mutant that form the biofilm of distinct nature were used for the model strains to test our method. During bacterial adhesion and biofilm maturation, EIS data were collected and equivalent circuit analysis was carried out to obtain constant phase element (CPE) values representing double-layer capacitance. Since the influence by the bacterial growth-related culture media condition was eliminated by adopting fresh electrolyte at the measurement, the contribution of attached bacteria and biofilm was exclusively measured. As a result, the bacterial adhesion at the early stage of biofilm development was specifically monitored from reduction in double-layer capacitance. Particularly, the plateau in double-layer capacitance appeared upon biofilm maturation, indicating that biofilm maturation could be expected beyond this point. In conclusion, this study found that measurement of double-layer capacitance based on EIS could provide a monitoring parameter suggesting bacterial adhesion and the initiation point of biofilm maturation.
开发有效的水系统生物膜控制策略已成为当今关注的焦点。电化学监测，特别是电化学阻抗谱（EIS），是处理与生物膜相关问题的有效方法之一。然而，目前使用的无氧化还原探针的 EIS 方法旨在检测所有来自介质成分、细菌和细菌代谢物产生的影响，这使得附着细菌和生物膜的信号减弱。在这项研究中，我们尝试使用双层电容改进 EIS 测量来监测细菌附着和生物膜成熟。在这种改进的方法中，我们通过减去细菌代谢引起的电解质干扰来最小化背景信号。使用具有不同性质生物膜的野生型铜绿假单胞菌 PA14 和 wspF 突变体作为模型菌株来测试我们的方法。在细菌附着和生物膜成熟过程中，收集 EIS 数据并进行等效电路分析，以获得代表双层电容的恒相元件（CPE）值。由于通过在测量时采用新鲜电解质消除了与细菌生长相关的培养基条件的影响，因此仅测量附着细菌和生物膜的贡献。结果，从双层电容的减少中特异性地监测到生物膜发展早期的细菌附着。特别是，在生物膜成熟时出现双层电容的平台，表明在此之后可以预期生物膜成熟。总之，本研究发现基于 EIS 的双层电容测量可以提供一个监测参数，提示细菌附着和生物膜成熟的起始点。
