Neuroblastoma cell-based tools for the detection of marine VGSC-blocking neurotoxins

Identifier:  TDX:4496

Handle: https://hdl.handle.net/20.500.11797/TDX4496

Authors:  Alkassar, Mounira

Abstract:
The presence of marine toxins like tetrodotoxins (TTXs), paralytic shellfish toxins (PSTs) and ciguatoxins (CTXs) in Europe and the fact that no antidote has yet been found, poisoning cases due to consumption of seafood products contaminated with these toxins are still an issue around the world. The need for high-throughput detection methods to protect consumers from the risks of these poisonings remains urgent. This thesis aims to contribute to the development of cell-based tools for the detection of marine toxins paving the way towards the implementation of low cost, simple, and reliable toxicological screening and quantification methods alternative to the mouse bioassay for food safety and environmental monitoring purposes. In order to achieve this objective, this thesis provides the optimisation of a colorimetric cell based assay for the detection of voltage gated sodium channel blockers (TTX and PSTs). The applicability of the assay to the analysis of pufferfish and shellfish is demonstrated. In addition, toxicity equivalency factors are established for TTX analogues purified from the liver of a puffer fish specimen. Cyclodextrin polymers are exploited as a new sustainable clean-up and pre concentration materials. Furthermore, the use of monoclonal antibody to neutralise TTX in naturally contaminated biological matrices is explored. Towards the development of cell based biosensor, Neuro-2a cells are immobilised on electrodes of different materials and their presence and dehydrogenase activity are assessed using different techniques. Finally, a proof of concept of the use of the developed technique as a powerful screening tool to monitor the presence of TTXs and CTXs in fish samples is demonstrated.