Research Grants 2001-2002

Development of Enzymatic Inhibition Bioelectrodes for the Direct Determination of Phycotoxins

Francesco Botré, PhD
Dipartimento di Controllo e Gestione Delle Merci del Loro Impatto Sull'Ambiente, Universittá Degli Studi Di Roma, Rome, Italy

The goal of this research program is to develop biosensor-based analytical methods for the analysis of phycotoxins (toxins produced by algae which are responsible, when ingested, of various diseases in man) in mussels. These new methods should at least integrate, but hopefully substitute, the commonly applied "global toxicity tests", i.e. highly invasive bioassays on mammalians (in which the mussel extract is either injected or mixed with the food), which are, at present, the only internationally recognized methods for the screening of these toxins in seafood.

Enzymatic inhibition biosensors (ElBs), being a particular form of response-based analytical devices, would reveal a good compromise between purely "biological" and "physico-chemical" techniques. An EIB represents in fact a sort of "artificial bioindicator", partially combining the flexibility of a biological effect-based test and the selectivity of a physico-chernical assay. In other words, the screening analysis to detect the possible contamination of seafood by phycotoxins would be carried out by "feeding the biosensor" and monitoring the alteration of a specific biochemical parameter, rather than "feeding the mouse" and following the development of generic toxic effects.

This second year of the project is aimed to improve the analytical performance of the lab- scale bienzymatic prototype already set up for the direct determination of algal toxins belonging to the DSP ("diarrhetic shellfish poisoning") group; at the same time, other biosensors of the same type will be developed, in view of the realization of a monoenzymatic bioelectrode. The immobilization of only one enzyme is indeed simpler and would markedly improve the lifetime of operation and the stability of the sensor, these parameters being critical towards the subsequent realization of disposable biosensors, produced by the technique of screen printing, to be used for timely planned monitoring of risky areas and possibly also for shipboard operations.