A simple Streptomyces spore-based impedimetric biosensor to detect lindane pesticide

Lindane is a pesticide potentially harmful to environment and human health and in general, its detection involves mostly tedious, expensive and time-consuming techniques. A new strategy to detect lindane can be focused on the activity of Streptomyces strain M7 (SM7), which is capable to grow in the presence of organochlorine pesticides (OCPs) as carbon source. On this regard, the aim of this work is to present an optimized design of a microbial biosensor prototype based on a SM7 spore platform to detect and quantify lindane by electrochemical impedance spectroscopy (EIS) as the transduction method. By means of this technique, the metabolic bacterial activity was evaluated by analyzing a set of electrical parameters calculated by fitting the measured impedance spectra through an equivalent electrical circuit. Activity studies were performed by incubating the SM7 spore platform with (optimized incubation conditions) and without (to be used in a practical biosensor) shaking in the presence of lindane. In all cases, bacterial activity was measured by the impedance changes produced in the cells due to lindane removal from the culture medium. This proposed label-free impedimetric biosensor is simple, cost-effective and feasible to detect changes in the lindane concentration as low as 120 μg L−1 in less than 2 days without sample pretreatment. In addition, the surface of electrodes can be reused for several different tests. This sensor prototype represents a valuable alternative for OCPs detection.