A microfluidic chip integrating electrochemical impedimetric immunosensors constructed by top-bottom opposite electrodes for rapid detection of peanut allergen-Ara h 1

Abstract

Developing a rapid and ultrasensitive immunosensor is significant for detecting allergenic contamination in food safety fields. This study reports a microfluidic biosensing device consisting of two top-bottom opposite electrode chips and a channel slab for constructing peanut allergen-Ara h 1 immunosensors. Under optimal fluidic manipulation (OFM), transporting an 80 μL aliquot of Ara h 1-containing phosphate buffer solution spiked by 2.5 mM Fe(CN)63−/4− mediator with a 50 μL/min flow rate for 2.5 min, the device can obtain better immunoreaction. The electron transfer resistance (Ret) of the label-free immunosensors was analyzed by electrochemical impedance spectroscopy (EIS) to quantify Ara h 1 immunoreaction. After performing OFM once, the linear range and the limit of detection were 1 pg/mL− 10 ng/mL and 3.9 fg/mL, respectively. Furthermore, the Ret response of the immunosensors increased with OFM times. The sensing device can detect the Ara h 1 concentration with good recovery (95 −103%) for the diluted supernatant extracted from standard peanut butter. The microfluidic device integrating EIS-based immunosensors exhibits rapid and ultrasensitive sensing properties with promising potential for label-free detection of allergens in food products.