title: A membrane-based ELISA assay and electrochemical immunosensor for microcystin-LR in water samples.
abstract: We describe within this paper the development of an affinity sensor for the detection of the cyanobacterial toxin microcystin-LR. The first stage of the work included acquiring and testing of the antibodies to this target. Following the investigation, a heterogeneous direct competitive enzyme-linked immunosorbent assay (ELISA) format for microcystin-LR detection was developed, achieving a detection limit, LLD(80) = 0.022 μg L(-1). The system was then transferred to an affinity membrane sorbent-based ELISA. This was an amenable format for immunoassay incorporation into a disposable amperometric immunosensor device. This membrane-based ELISA achieved a detection limit, LLD(80) = 0.06 μg L(-1). A three-electrode immunosensor system was fabricated using thick-film screen-printing technology. Amperometric horseradish peroxidase transduction of hydrogen peroxide catalysis, at low reducing potentials, versus Ag/AgCl reference and carbon counter electrodes, was facilitated by hydroquinone-mediated electron transfer. A detection limit of 0.5 μg L(-1) for microcystin-LR was achieved. Similar levels of detection could be obtained using direct electrochemical sensing of the dye produced using the membrane-based ELISA. These techniques proved to be simple, cost-effective, and suitable for the detection of microcystin-LR in buffer and spiked tap and river water samples.
authors.affiliation: Cranfield Health, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, England, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Lotierzo
authors.forename: R
authors.initials: R
authors.lastname: Abuknesha
authors.forename: F
authors.initials: F
authors.lastname: Davis
authors.forename: I E
authors.initials: IE
authors.lastname: Tothill
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D003429:Cross Reactions; D055664:Electrochemical Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D055767:Immobilized Proteins / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008387:Marine Toxins; D008567:Membranes, Artificial; D052998:Microcystins / Q000032:analysis* / Q000737:chemistry; D010456:Peptides, Cyclic / Q000032:analysis / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D052160:Benzothiazoles; D055767:Immobilized Proteins; D007074:Immunoglobulin G; D008387:Marine Toxins; D008567:Membranes, Artificial; D052998:Microcystins; D010456:Peptides, Cyclic; D013451:Sulfonic Acids; D014874:Water Pollutants, Chemical; C063998:nodularin; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C057862:cyanoginosin LR