SENSING TOXICANTS IN MARINE WATERS MAKES SENSE USING BIOSENSORS

Co‐financed by the EU under "The Ocean of Tomorrow" programme, the SMS project promotes the development of novel sensing devices for marine environmental protection. The overriding goal of the project is to develop a novel automated networked system that will enable real‐time in‐situ monitoring of marine water chemical and ecological status in coastal areas by the detection of a series of contaminants. In this context, we are developing optical and electrochemical biosensors to detect four marine algal toxins: Saxitoxin (STX), Palytoxin (PTX), Okadaic Acid (OA) and Domoic Acid (DA), present at ultratraces levels in seawater. Regarding STX, a low molecular weight neurotoxin mainly produced by certain marine Dinoflagellates and responsible for causing paralytic shellfish poisoning, we have developed an aptamer‐based optical biosensors. In fact, optically labelled saxitoxin‐binding aptamer can signal the target presence through a binding‐induced conformational change which brings the fluorophore close to the quencher thus decreasing the fluorescence signal. The proposed method is simple, high specific and selective even if a preconcentration step is needed. Alternatively, we are also working on a flow‐injection immunoassay (FI‐IA) method with amperometric or colorimetric detection for saxitoxin determination. This system combines the rapidity and reproducibility of the flow‐injection technique with the high selectivity and sensitivity of immunochemical reactions. Regarding OA, a lipophilic marine toxin produced by Dinophysis and Prorocentrum which is responsible for causing diarrheic shellfish poisoning, we have developed a colorimetric assay based on the inhibition of protein phosphatase type 2A (PP2A) by the toxin.. We propose a colorimetric assay in which the activity of PP2A is determined by measuring the rate of color production from the production of yellow p‐nitrophenol using p‐nitrophenyl phosphate as the substrate. The authors would like to acknowledge the financial support from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 613844.