title: Magnetic particle-based enzyme assays and immunoassays for microcystins: from colorimetric to electrochemical detection.
abstract: In this work, magnetic particles (MPs) are used as supports for the immobilization of biorecognition molecules for the detection of microcystins (MCs). In one approach, a recombinant protein phosphatase 1 (PP1) has been conjugated to MPs via coordination chemistry, and MC-LR detection has been based on the inhibition of the enzyme activity. In the other approach, a monoclonal antibody (mAb) against MC-LR has been conjugated to protein G-coated MPs, and a direct competitive enzyme-linked immunoparticle assay (ELIPA) has been then performed. Conjugation of biomolecules to MPs has been first checked, and after optimization, MC detection has been performed. The colorimetric PPIA with PP1-MP and the best ELIPA strategy have provided limits of detection (LOD) of 7.4 and 3.9 μg/L of MC-LR, respectively. The electrochemical ELIPA has decreased the LOD to 0.4 μg/L, value below the guideline recommended by the World Health Organisation (WHO). The approaches have been applied to the analysis of a cyanobacterial culture and a natural bloom, and MC equivalent contents have been compared to those obtained by conventional assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results have demonstrated the viability of the use of MPs as biomolecule immobilization supports in biotechnological tools for MCs monitoring.
authors.affiliation: IRTA, Carretera de Poble Nou, km 5.5, 43540 Sant Carles de la Ràpita, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Reverté
authors.forename: Diana
authors.initials: D
authors.lastname: Garibo
authors.forename: Cintia
authors.initials: C
authors.lastname: Flores
authors.forename: Jorge
authors.initials: J
authors.lastname: Diogène
authors.forename: Josep
authors.initials: J
authors.lastname: Caixach
authors.forename: Mònica
authors.initials: M
authors.lastname: Campàs
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D003124:Colorimetry; D004563:Electrochemistry; D007098:Imino Acids / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D060328:Magnetic Phenomena; D052998:Microcystins / Q000032:analysis* / Q000276:immunology; D009532:Nickel / Q000737:chemistry; D054645:Protein Phosphatase 1 / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D007098:Imino Acids; D052998:Microcystins; D011994:Recombinant Proteins; D009532:Nickel; D054645:Protein Phosphatase 1; C008109:iminodiacetic acid