Integration of LSPR-based colorimetric sensing and smartphone-assisted dual read-out microfluidic paper-based analytical devices for rapid detection of Pb2+ in environmental samples

This work presents the development of metronidazole-functionalized silver nanoparticles (MTZ-AgNPs) based LSPR sensing for rapidly detecting Pb2+ ions. Advanced characterization techniques provided insights into the morphological, structural, and surface properties of the MTZ-AgNPs. The sensing mechanism and selective interaction of MTZ-AgNPs with Pb2+ ions were explored, elucidating the binding process. The MTZ-AgNPs-based LSPR sensor showed a very low detection limit of 0.018 mu M (3.73 ppb). MTZ-AgNPs-based sensing material was also integrated with smartphone-assisted dual read-out microfluidic paper-based analytical devices (mu PADs) for rapid detection of Pb2+ ions. The fabricated devices were associated with color and height changes. The detection limits of developed sensors were 0.05 mu M (10.36 ppb) for color change and 0.1 mu M (20.72 ppb) height changes associated with dual read-out microfluidic paper-based analytical devices. The practicality of the MTZ-AgNPs-based sensing strategy was demonstrated by detecting Pb2+ in various samples, including soil, rock, air particulates, and water.