Distance-Based Paper Microfluidic Analytical Device Using Aptamer Functionalized Silver Nanomaterial for Aflatoxin B1 Quantification in Food Products

Abstract

In this article, a simple and affordable distance-based paper analytical device (dPAD) for the quantitative detection of aflatoxin B1 (AFB1) in agricultural food products has been successfully developed. The sensing assay is based on the salt-induced aggregation of silver nanoparticles (AgNPs), which exhibit a localized surface plasmon resonance (LSPR) response. This aggregation is triggered by the specific binding between AFB1 and aptamers pre-deposited on the detection zone of the sensor. When AFB1 binds to the aptamer, the released AgNPs interact with salt flowing through the channel, leading to nanoparticle aggregation and a visible colour change from yellow to orange-brown. The concentration of AFB1 can then be easily determined by measuring the length of the resulting colour band along the channel. The sensor provided a linear range between 0.3 and 0.8 ng mL^-1 (R² = 0.9986) with a detection limit (LOD) of 0.05 ng mL^-1, with the fast reaction time of 8 min. It also exhibits excellent detection selectivity, with no significant interference from other compounds. The method demonstrates excellent accuracy and precision for AFB1 monitoring in food products, including corn, wheat, and peanut, with recovery ranging from 95.0% to 105.0% with the highest relative standard deviation (RSD) of 4.8%. By integrating microfluidics, nanomaterials, and aptamers, this technique shows great promise for the sensitive and selective detection of AFB1. Moreover, it represents a significant step forward in developing low-cost analytical platforms for a wide range of target molecules, making it highly applicable for real-world applications.