An improved sensitive assay for the detection of PSP toxins with neuroblastoma cell-based impedance biosensor.

Paralytic shellfish poisoning (PSP) toxins are well-known sodium channel-blocking marine toxins, which block the conduction of nerve impulses and lead to a series of neurological disorders symptoms. However, PSP toxins can inhibit the cytotoxicity effect of compounds (e.g., ouabain and veratridine). Under the treatment of ouabain and veratridine, neuroblastoma cell will swell and die gradually, since veratridine causes the persistent inflow of Na(+) and ouabain inhibits the activity of Na(+)/K(+)-ATPases. Therefore, PSP toxins with antagonism effect can raise the chance of cell survival by blocking inflow of Na(+). Based on the antagonism effect of PSP toxins, we designed an improved cell-based assay to detect PSP toxins using a neuroblastoma cell-based impedance biosensor. The results demonstrated that this biosensor showed high sensitivity and good specificity for saxitoxins detection. The detection limit of this biosensor was as low as 0.03 ng/ml, which was lower than previous reported cell-based assays and mouse bioassays. With the improvement of biosensor performance, the neuroblastoma cell-based impedance biosensor has great potential to be a universal PSP screening method.