An ultrasensitive non-noble metal colorimetric assay using starch-iodide complexation for Ochratoxin A detection.
Anal Chim Acta
; 1135: 29-37, 2020 Oct 23.
Article
em En
| MEDLINE
| ID: mdl-33070856
ABSTRACT
Colorimetric sandwich-type biosensors that can both provide sensitivity competitive with fluorescence-based approaches, and leverage reagents that are cost-effective, widely available and as safe as possible, are highly sought after. Herein, we demonstrate an alternative highly-sensitive colorimetric method for paper-based sandwich-type biosensing that uses starch-iodide complexation to simplify practical biosensing using ubiquitous reagents. Targeting the mycotoxin ochratoxin A (OTA), a covalently-immobilised OTA antibody on a cellulose surface captures OTA and forms a sandwich with OTA aptamer-conjugated glucose oxidase. Adding the chromogenic reagents at an optimized concentration, a distinct blue color develops within 30 min, offering excellent contrast with the clear/white of the negative sample. With a sampling volume down to just 5 µL, the assay exhibits concentration limits of detection and quantitation of 20 and 320 pg mL-1, respectively, and a linear range from 10-1 to 105 ng mL-1 (R2 = 0.997). The method displays excellent selectivity against related mycotoxins, excellent %recovery (95-117%) and robust operation in complex matrices (beer, urine and human serum), with no significant difference versus gold-standard liquid chromatography. Along with its excellent analytical performance, this assay benefits from non-toxic and extremely cheap reagents that can be safely disposed of in the field, and presents an attractive alternative to toxic dyes and nanoparticles.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Técnicas Biossensoriais
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Aptâmeros de Nucleotídeos
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Ocratoxinas
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article