A label-free liquid crystal droplet-based sensor used to detect lead ions using single-stranded DNAzyme

Abstract

A liquid crystal (LC) droplet pattern-based sensor used to detect lead ions (Pb2+) in phosphate buffer saline (PBS) solution using single-stranded DNAzyme has been reported. When Pb2+ were present, it bound to the DNAzyme, leading to the release of tetradecyltrimethylammonium bromide (OTAB). These OTAB molecules were absorbed onto the aqueous/LC interface and helped in arranging the LC orientation. A planar-to-homeotropic order transition of LC droplets was triggered during this event. The reported naked-eye optical sensor possesses a limit of detection (LOD) of about 0.7 nM in PBS and 0.8 nM in tap water. The proposed LC droplet-based sensor was highly sensitive and selective for label-free Pb2+ detection. This sensor also provided a platform for the detection of proteins, DNA, and other metal ions by modifying the receptor. © 2020 Elsevier B.V.