A novel and functional assay for pharmacological effects of marine toxins, saxitoxin and tetrodotoxin by cardiomyocyte-based impedance biosensor

Saxitoxin (STX) and tetrodotoxin (TTX) are highly toxic marine toxins targeting site 1 of α subunit of voltage-dependent sodium channels (VDSCs). Both of them disturb sodium channels' function by inhibition of ion current through the channels. And they are probably involved in some ion channel diseases, such as cardiovascular diseases and neurodegenerative diseases. The present work described a novel and functional method for detecting the pharmacological effects of STX and TTX using the cardiomyocyte-based biosensor. This biosensor was based on impedance technology through a label-free and real-time detection system which could monitor the cardiomyocyte growth and beating status simultaneously. The parameters of the cardiomyocyte-based biosensor, cell index, beating rate, and amplitude were analyzed to determine the biosensor performance under the treatment of toxins. The results showed that beating rate of this biosensor was a sensitive parameter to STX and TTX, and the detection limit of this biosensor was 0.087 and 89 ng/ml for STX and TTX, respectively. It could be concluded that the cardiomyocyte-based impedance biosensor would be a promising tool for quantitative analysis of the pharmacological effects of these two toxins.