Highly sensitive and selective optical sensor for lead ion detection based on liquid crystal decorated with DNAzyme

Lead ions (Pb2+) are one of the major environmental pollutants that are dangerous for human health, thus the detection methods of Pb2+ become very important as well. However, most reported techniques suffer from drawbacks such as long time, expensive equipment and complicated testing process, which prevent the use of real-time application. Herein, we demonstrate a novel liquid crystal optical sensor for detection of Pb2+ based on DNAzyme and its combined strand. The ordered and disordered configuration of liquid crystals, induced by complementary DNA strand and catalytically cleaved DNA in presence of lead ion separately, leads to dark and bright optical image under POM. The proposed naked-eye optical sensor possesses an extremely broad detection range of Pb2+ from 50 nM to 500 mu M, with a low detection limit about 36.8 nM. The sensor also demonstrates high selectivity of Pb2+ from many other metal ions. The proposal LC sensor is highly sensitive and selective for Pb2+ detection, which provides a novel platform for other heavy metal, DNAs or antigen in biological and chemical fields by modifying sensing molecules. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement