A Paper/Polymer Hybrid Microfluidic Nanosensing Rotary Chip: From Efficient Reagent Delivery to Multiplexed Detection of Toxins.

In this study, we present a novel paper/polymer hybrid microfluidic Rotary Chip, integrated with aptamer-functionalized graphene oxide (GO) nanosensors, which enables not only efficient reagent delivery but also quantitative multiplexed detection. Rapid simultaneous detection of two major aflatoxins, aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2), was successfully achieved to demonstrate the effectiveness of this hybrid rotary chip. Aflatoxins, as potent natural carcinogens, represent a significant global food safety challenge. Rapid and sensitive detection methods are crucial for effective monitoring. The RotaryChip design involves manually rotating the top poly(methyl methacrylate) (PMMA) plate over the bottom plate around a central screw, providing a simple strategy for rapid and efficient reagent delivery for multiplexed assays and high-throughput analysis without the need for sophisticated external pumps or pneumatic valves. The paper substrate in this hybrid microfluidic plate facilitates the facile integration of nanosensors in detection wells without the need for elaborate surface modification. The entire assay was completed in approximately 30 min and did not involve any washing steps. The platform achieved detection limits as low as 0.7 μg/kg for AFB1 and 0.5 μg/kg for AFB2. We further validated the platform by accurately detecting and quantifying AFB1 and AFB2 in spiked cooking oil samples with high specificity. Owing to its high simplicity and specificity, fast analysis, simple and efficient reagent delivery, and its multiplexing and quantitative capability, this paper/PMMA hybrid microfluidic nanosensing platform has tremendous potential for environmental and food safety surveillance, including multiplexed detection of different toxins and pathogens, particularly in low-resource settings.