Monitoring Domoic Acid in Marine Phytoplankton by Disposable Immunosensors

Advances in sensor technology have allowed the significant progress in the monitoring of noxious compounds in the sea, providing real-time detection so as to prevent risks associated with the diffusion and dispersion of toxic substances in the environment. An important element in the overall picture is the harmful algal blooms which pose serious threats to marine ecosystems through the production of toxins that accumulate in filter-feeders and ultimately impact both human health and fisheries. Domoic acid is a neurotoxic amino acid produced by marine planktonic diatoms of the genus Pseudo-nitzschia. Here we monitored domoic acid production by natural Pseudo-nitzschia populations in phytoplankton samples collected along the Middle Tyrrhenian coast, over the course of one year, using selective immunosensors based on screenprinted electrodes, using differential pulse voltammetry as the electrochemical technique, to yield quantitative outputs. In this work, disposable devices have been applied for monitoring the production of domoic acid on algal extracts and the results have been validated by conventional high pressure liquid chromatography-ultraviolet detection methods. The data obtained revealed the presence of domoic acid in Italian phytoplankton, especially in coastal impacted areas, highlighting the potential risk of toxin entering into marine food webs and the environment. Immunosensors based on screen-printed electrodes prove to be effective tools for annual monitoring of domoic acid in seawater samples, thus providing a reliable early warning system relative to health and economic impact of algal toxins.