Abstract
Due to the expanding occurrence of marine toxins, and their potential impact on human health, there is an increased need for tools for their rapid and efficient detection. We give an overview of the use of magnetic beads (MBs) for the detection of marine toxins in shellfish and fish samples, with an emphasis on their incorporation into electrochemical biosensors. The use of MBs as supports for the immobilization of toxins or antibodies, as signal amplifiers as well as for target pre-concentration, is reviewed. In addition, the exploitation of MBs in Systematic Evolution of Ligands by Exponential enrichment (SELEX) for the selection of aptamers is presented. These MB-based strategies have led to the development of sensitive, simple, reliable and robust analytical systems for the detection of toxins in natural samples, with applicability in seafood safety and human health protection.
Highlights
Oceans and their resources have sustained nations for millennia, with seafood being a strong part of cultural identity and tradition
Diverse toxins cause different intoxications, which are grouped according to their effects: diarrheic shellfish poisoning (DSP), paralytic shellfish poisoning (PSP), amnesic shellfish poisoning (ASP), neurologic shellfish poisoning (NSP), ciguatera fish poisoning (CFP) and pufferfish poisoning [3]
Protein G-coated magnetic beads (MBs) were functionalized with anti-AZA polyclonal antibody, and free AZA competed with HRP-labelled AZA (HRP–AZA) for binding to the immobilized antibody in suspension, achieving LODs of 1.1 and 1.0 μg/L, using 3,3, 5,5 -tetramethylbezidine (TMB) as an enzyme mediator and optical and electrochemical detection, respectively
Summary
Oceans and their resources have sustained nations for millennia, with seafood being a strong part of cultural identity and tradition. Cell-based assays (CBAs) are easy to perform, give an overall view of the toxicity of a sample and can detect the presence of unknown toxins. They show high variability, which hampers their harmonization, and may not be able to discriminate compounds that share the same mechanism of action. Immunoassays, based on the affinity between antibodies and target antigens, show high sensitivity. Whilst the structural recognition may not be necessarily related to the toxicity, antibodies are easier to obtain than receptors, and are more robust, facilitating an easier implementation of immunoassays, as well as immunosensors, which have the added potential benefit of being miniaturisable and portable [7,8]
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