Innovative electrochemical biosensor for toxicological investigations on algae and cyanobacteria

An electrochemical biosensor is presented that directly reflects the metabolic activity of prokaryotic and eukaryotic cells. This biosensor can be used measure the biological activity of bacteria, yeasts and mammalian cells. This makes the sensor interesting for various applications in industry and science. A possible application is bioprocess control, monitor activities from yeasts, bacteria and fungi to increase the yield. Other applications are starter culture quality studies in the food industry and cytoxicological evaluation with mammalian cells. Our latest investigations additionally indicate the applicability of the electrochemical biosensor to measure algae and cyanobacteria. In our investigations, we were able to show that it was also possible to detect photosynthetic organisms with the electrochemical measurement method, used for investigations on prokaryotic and eukaryotic organisms before. Therefore, this the present study demonstrates an alternative to using this electrochemical biosensor equipped with alga and cyanobacteria for toxicological investigations based on selected test chemicals. The results of this study show a good correlation with those from reference methods, such as the Algal Growth Inhibition Test and the Microtox Test. The advantages of the new electrochemical biosensor are easy handling and shorter measurement time by using different types of test organisms. The evaluation of the sensor signal is based on the current-time curves of a potentiostatic measurement produced by the detection of microbially reduced mediator molecules immobilized in a gel structure. The mediator molecules are reduced during the measurement process. The reduced mediator molecules produce a current signal, which rapidly provides information about the vigor and vitality of living bacteria, yeasts, fungi or cells.