Detection of environmental pollutants with oxidoreductases

Biomimetics is an engineering activity which aims to convert principles of biological function into human technology. A bio-device using information transfer-conversion system of the creature is a biosensor. Organic materials are quite fascinating due to availability of many metastable states which is considered to play a pivotal role for the next-generation electronics. Especially, "Organic Iontronics" which are dealing with the devices and applications using functions of ions etc. attracts much attention. The word "Iontronics" is still unfamiliar words and has been created by the fusion of two words "Ion" and "Electronics". The most familiar area biotechnology which is based on amicable use of unique biological function towards betterment of human life and environmental conservation cannot deny the important role played by the ions. Hydrogen peroxide (H2O2) is a commonly used chemical in industries such as pharmaceutical, food, plastic processing, cosmetics, and cleaning. Higher concentration of H2O2can cause serious damage to skin if direct contact has been made. It is highly possible that hydrogen peroxide being released to the natural environment through these industrial processes. Even low concentrations of H2O2can change the ecosystem balance beyond acceptable limits in the long term if it is added to natural water streams. H2O2is not only has its presence in industrial waste, but also in many biological processes such as highly selective enzyme catalytic reactions. The concentrations in these biological processes are very small and therefore it is very important to measure H2O2in low concentrations accurately. About a novel technique of developing a nano-structured polypyrrole biosensor for measurement of very low concentrations of hydrogen peroxide in liquid media has been discussed. The proposed fabrication method is very effective in growing a nano-structured conductive polymer layer on a plannar conducting substrate. In addition, enzyme loading was done under a high electric field of 1 kV/m. The developed sensor provides a linear range of 0-200 μmol/l of hydrogen peroxide and a measurement sensitivity of 6.5 Acm-(mol/l)-. © 2017 Institute of Electrical Engineers of Japan. All rights reserved.