Cost-effective and rapid detection of tetrodotoxin using indium tin oxide electrodes via in vitro electrophysiology and electrochemistry

Pandurangi, N. A. C., Santafe, M. M., Tudo, A., Ozsoy, N., Sureda, F. X., Dallas, M. L. ORCID: https://orcid.org/0000-0002-5190-0522 and Katakis, I. (2025) Cost-effective and rapid detection of tetrodotoxin using indium tin oxide electrodes via in vitro electrophysiology and electrochemistry. Toxins, 17 (9). 462. ISSN 2072-6651 doi: 10.3390/toxins17090462

Abstract/Summary

The real-time, cost-effective detection of marine toxins like tetrodotoxin (TTX) remains a significant challenge for the scientific community. Traditional methods, including cell-based assays (CBAs), high-performance liquid chromatography (HPLC), and automated patch clamp (APC), are time-consuming, requiring expensive lab-based equipment and highly trained personnel. Enzyme-linked immunosorbent assays (ELISAs), lateral flow assays (LFAs), and immunosensors may not be suitable for toxin analogues. Thus, a simplified approach has been developed in this study, which involves the electrophysiological and electrochemical interrogation of N2a cells grown on ITO-coated glass electrodes by measuring extracellular field potentials (EFP) in conjunction with whole-cell patch clamp recordings and electrochemical impedance spectroscopy (EIS) measurements both before and after incubation with TTX. The ITO substrate proved biocompatible and non-toxic for N2a cells. TTX exposure caused 102% inhibition in EFP values at 300 nM, confirmed by sodium current inhibition of 93% at 300 nM and 22% at 1 nM in patch clamp studies (IC50 = 6.7 nM). EIS measurements indicated concentration-dependent impedance changes in the range of 6–300 nM. This research aims to provide a proof-of-concept for integration of electrophysiological and electrochemical approaches to simplify toxin detection systems.