Barcode-style lateral flow immunochromatographic strip for the semi-quantitative detection of ochratoxin A in coffee samples

Abstract

Ochratoxin A (OTA) is a mycotoxin contaminating agricultural products produced by fungi, associated with important toxic effects. Thus, the development of fast, sensitive, and economical approaches for OTA detection is crucial. In this study, a barcode-style lateral flow assay for the semi-quantitative detection of OTA in coffee samples was developed. To achieve this goal, a BSA-OTA complex was immobilized in three test zones to compete with OTA molecules in the sample for binding with anti-OTA antibodies labeled with gold nanoparticles. Different concentrations of OTA in the sample produced distinct colour patterns, allowing semi-quantification of the analyte. The assay exhibited high sensitivity, with a limit of detection of 2.5 µg.L⁻¹, and high reproducibility, with variation coefficient values between 2% and 13%. Moreover, the colour patterns obtained in the analysis with coffee samples were similar to the results obtained with standard OTA solutions, demonstrating a reliable applicability in real samples.

Keywords:

• Ochratoxin A
• lateral flow assay
• semi-quantitative
• gold nanoparticles
• coffee

Acknowledgements

This study used the facilities and equipment of the Functional Nanomaterials Laboratory and the Carlos Alberto Redins Cellular Ultrastructure Laboratory. Our thanks to both laboratories for providing the equipment and technical support for the experiments.

Authors contributions

LACA, JPO and MCCG conceived the project. LACA and MDLJ performed the experiments, characterizations, and analyses. LACA, MDLJ wrote the article. FVC and MCCG reviewed and edited the writing. MCCG and JPO guided the investigation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico, Financiadora de Estudos e Projetos, Fundação de Amparo à Pesquisa e Inovação do Espírito Santo, and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.