Oxygen-induced dual-signal point-of-care testing aptasensor for aflatoxin B1 detection using platinum nanoparticle catalysis in visual fluorometry and gravimetry.

Point-of-care testing (POCT) has experienced rapid development owing to its advantages of rapid testing, low cost and strong operability, making it indispensable for analyte detection in outdoor or rural areas. In this study, we propose a novel method for the detection of aflatoxin B (AFB) using a dual-signal readout approach within a unified system. This method employs dual channel modes, namely visual fluorescence and weight measurements, as the signal readouts. Specifically, a pressure-sensitive material is utilized as a visual fluorescent agent, its signal can be quenched in the presence of high oxygen pressure. Additionally, an electronic balance, commonly used for weight measurement, is adopted as another signal device, where the signal is generated through the catalytic decomposition of HO by platinum nanoparticles. The experimental results demonstrate that the proposed device enables accurate AFB detection within the concentration range of 1.5-32 μg mL, with a detection limit of 0.47 μg mL. Moreover, this method has been successfully applied for practical AFB detection with satisfactory results. Notably, this study pioneers the use of a pressure-sensitive material as a visual signal in POCT. By addressing the limitations of single-signal readout approaches, our method fulfills requirements of intuitiveness, sensitivity, quantitative analysis and reusability.