Department Environmental Toxicology

Impedance Biosensor

The cell electric impedance methodology that we are developing uses the rainbow trout (Oncorhynchus mykiss) gut and gill cells cultured on biochips to detect toxic substances in water. The project involves several different disciplines including cell biology, electrochemistry and ecotoxicology. We have tested various organic pollutants in benchmarking tests and a range of water effluent samples using this system. The overall goal of this project is to establish the proof-of-principle and engineer the biosensor using this technique for monitoring ecotoxicity in the aquatic environment.  

Aquatic environment monitoring is integral to the sustainable management of the deteriorating freshwater resources of our planet, but there is few suitable system that is able to reflect ecotoxicity test standards and monitor water quality based on overall toxicity to a biological system. The cell electric impedance method development is part of the Nano-Tera project “Envirobot project (http://wp.unil.ch/envirobot/) that involves multiple research partners across Switzerland in Dübendorf (Eawag), Lausanne (EPFL and UNIL) and Sion (HES-SO), to develop an autonomously swimming robot with various integrated (bio)sensors for detecting aquatic toxicity. We utilise the RTgutGC and RTgill-W1 cells and a cell electric impedance-based system with electrode-embedded culturing surface and impedance measuring unit. The cell electric impedance can be measured to indicate the cell status including growth, migration, morphology, cell-to-matrix and cell-to-cell interactions. The perturbation of the cells by chemical stimuli can be indicated in the changes of impedance. 

We have systematically tested the cell electric impedance system with: (i) chemicals commonly found in the aquatic environment; (ii) water effluent samples; (iii) prolonged exposure to PAHs (polycyclic aromatic hydrocarbons); (iv) detection of sensitivity after long-term storage of cells; (v) comparison with conventional cytotoxicity methods; (vi) correlation to in vivo data. We are currently working on engineering and integrating the cell impedance unit into the Envirobot. These investigations will help us explore and establish the feasibility of using the fish cell electric impedance system for toxicity monitoring of the aquatic environment. Moreover, this potential monitoring system will complement the search for alternatives of animal testing.