A continuous rise in the wastes from industrial effluents, bio-waste, and pharmaceuticals has deteriorated surface water and drinking water sources. Standard laboratory tests of total coliform are time-consuming and logistically inefficient for field data generation. Better and portable sensing technologies are needed. This paper reports an electrical impedance spectroscopic technique incorporated in a micro-fluidic chip with interdigitated microelectrodes to monitor the growth of microbial cells. Lag, log, and stationary phases of Escherichia coli cell growth with an integrated electrode are successfully detected, for samples of reverse osmosis water, standard treated tap water, and recycled water respectively. The results indicate that reverse osmosis water has a higher probability of contamination with bacterial pathogens compared to the other two types of water samples when subjected to the same amount of added nutrients. The statistical analysis shows a possible single detection range with higher-order regression, and repeat use of a single chip with the electrode was found to be within an acceptable limit. The interdigitated electrodes exposed to in-situ cell growth conditions and repeated electrical measurements have shown a promise for possible periodic or continuous monitoring. The paper further identifies several complimentary analysis methodologies that are robust towards phase noise in the measured impedance and are suited particularly for early-stage detection of bacterial contamination. The cell adhesion tendencies over the microelectrode due to the electric field need to be further analyzed.

工业废水、生物废物和药物产生的废物不断增加，导致地表水和饮用水源不断恶化。总大肠菌群的标准实验室测试对于现场数据生成来说既耗时又在后勤上效率低下。需要更好的便携式传感技术。本文报告了一种电阻抗光谱技术，该技术结合在具有叉指微电极的微流控芯片中，以监测微生物细胞的生长。大肠杆菌的滞后相、对数相和固定相分别针对反渗透水、标准处理过的自来水和循环水样品，成功检测到带有集成电极的细胞生长。结果表明，与其他两种类型的水样相比，当添加相同数量的营养物质时，反渗透水被细菌病原体污染的可能性更高。统计分析显示了具有高阶回归的可能的单一检测范围，并且发现单个芯片与电极的重复使用在可接受的限度内。暴露于原位细胞生长条件和重复电测量的叉指电极已显示出可能进行定期或连续监测的前景。该论文进一步确定了几种互补的分析方法，它们对测量阻抗中的相位噪声具有鲁棒性，特别适用于细菌污染的早期检测。由于电场引起的微电极上的细胞粘附趋势需要进一步分析。