Aptamer-based colorimetric determination of Pb2+ using a paper-based microfluidic platform

In this research, a novel paper-based microfluidic aptasensor was designed in order to detect different concentrations of lead in water. The principle based on which this aptasensor works is the interaction of gold nanoparticles with NaCl which leads to a color change from red to purple in the presence of lead ions due to AuNP aggregation. Furthermore, two types of filter paper, namely Whatman No.1 and nylon filter papers, were used as the platform of this paper-based microfluidic assay, and the properties of each one was investigated. It was seen that Pb2+ can be detected with linear trends for the calibration of each paper type at concentrations within the 10 nM to 1 mM range in both Whatman No.1 and nylon filter papers. A detection limit of 1.2 nM and 0.7 nM was obtained for Whatman No.1 and nylon filter papers, respectively. Moreover, the Whatman No.1 filter paper was used for the detection in real water samples, and it showed good potential for the detection of Pb2+ in environmental samples.