Fabrication of microfluidic device for Aflatoxin M1 detection in milk samples with specific aptamers

Aruna Kasoju,Jyotsnendu Giri,Amer M Alanazi,Sonu Gandhi,Azmat Ali Khan,Mashooq Ahmad Bhat,Deepshikha Shahdeo,Narlawar Sagar Shrikrishna,Subhasis Mahari

doi:10.1038/s41598-020-60926-2

Abstract

This study describes the colorimetric detection of aflatoxin M1 (Afl M1) in milk samples using a microfluidic paper-based analytical device (µPAD). Fabrication of µPADs was done using a simple and quick approach. Each μPAD contained a detection zone and a sample zone interconnected by microchannels. The colorimetric assay was developed using unmodified AuNPs as a probe and 21-mer aptamer as a recognition molecule. The free aptamers were adsorbed onto the surface of AuNPs in absence of Afl M1, even at high salt concentrations. The salt induced aggregation of specific aptamers occurred in presence of Afl M1. Under optimum conditions, the analytical linear range was found to be 1 µM to 1 pM with limit of detection 3 pM and 10 nM in standard buffer and spiked milk samples respectively. The proposed aptamer based colorimetric assay was repeatable, quick, selective, and can be used for on-site detection of other toxins in milk and meat samples.

Highlights

This study describes the colorimetric detection of aflatoxin M1 (Afl M1) in milk samples using a microfluidic paper-based analytical device
A plethora of analytical techniques are available for aflatoxin M1 detection, ranging from chromatography and HPLC-MS used for regulatory control in official laboratories to rapid test kits for grain silos and farmers, especially for surveys when outbreaks occur[10,11]
We have reported the detection of Afl M1 using aptamer/AuNPs (Afl M1 apt/AuNPs) complex on a paper microfluidic device

Summary

Introduction

This study describes the colorimetric detection of aflatoxin M1 (Afl M1) in milk samples using a microfluidic paper-based analytical device (μPAD). In order to form the regulations in food industry, to ensure food safety, potential on-site novel aflatoxin detection systems including dipstick, microarray chips, hyperspectral imaging, electronic noses, molecular imprinted polymers (MIPS) and aptamer based biosensors using nanoparticles have been developed[19]. These technologies have www.nature.com/scientificreports relevance in remote areas, and resource limited developing countries like India due to its stability, ease of production, and use[20]. The developed method can be a useful tool for on-site monitoring of aflatoxin in rural areas for economically backward farmers

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Conclusion