An improved functional assay for rapid detection of marine toxins, saxitoxin and brevetoxin using a portable cardiomyocyte-based potential biosensor

• A portable cardiomyocyte-based potential biosensor is established to rapidly detect saxitoxin (STX) and brevetoxin (PbTX-2).
• The potential biosensor can record high consistent and quite regular cardiomyocytes extracellular field potential (EFP) signals for 60 h.
• The potential biosensor can detect 0.35 ng/ml STX and 1.55 ng/ml PbTX-2 within 5 min.

Saxitoxin (STX) and brevetoxin (PbTX-2), which are produced by marine dinoflagellates, are highly-toxic marine toxins targeting separate sites of the α subunit of voltage-dependent sodium channels (VDSCs). In this work, a portable cardiomyocyte-based potential biosensor is designed for rapid detection of STX and PbTX-2. This potential biosensor is constructed by cardiomyocyte and microelectrode array (MEA) with a label-free and real-time wireless 8-channel recording system which can dynamically monitor the multisite electrical activity of cardiomyocyte network. The recording signal parameters, spike amplitude, firing rate and 50% of spike potential duration (SPD50) extracted from extracelluar field potential (EFP) signals of the potential biosensor is analyzed to quantitatively evaluate toxicological risk of STX and PbTX-2. Firing rate of biosensor signals presents high sensitivity to STX with the detection limit of 0.35 ng/ml within 5 min. SPD50 shows high sensitivity to PbTX-2 with the detection limit of 1.55 ng/ml within 5 min. Based on the multi-parameter analysis, cardiomyocyte-based potential biosensor will be a promising tool for rapid detection of these two toxins.