Integrated electrochemical biosensor based on algal metabolism for water toxicity analysis

International audienceAn autonomous electrochemical biosensor with three electrodes integrated on the same silicon chip dedicated to the detection of herbicides in water was fabricated by means of silicon-based microfabrication technology. Platinum (Pt), platinum black (Pt Bl), tungsten/tungsten oxide (W/WO3) and iridium oxide (Pt/IrO2) working ultramicroelectrodes were developed. Ag/AgCl and Pt electrodes were used as reference and counter integrated electrodes respectively. Physical vapor deposition (PVD) and electrodeposition were used for thin film deposition. The ultramicroelectrodes were employed for the detection of O2, H2O2 and pH related ions H3O + /OH-, species taking part in photosynthetic and metabolic activities of algae. By measuring the variations in consumption-production rates of these electroactive species by algae, the quantity of herbicides present at trace level in the solution can be estimated. Fabricated ultramicroelectrodes were electrochemically characterized and calibrated. Pt Blac