Lateral Flow Nucleic Acid Biosensors For Detection Of Copper(Cu²⁺) And Lead(Pb²⁺)

It has long been beleived that heavy metals possess many adverse health effects. Uncontrolled industrialization has released heavy metal pollution in the world. Heavy metal pollutants damage organ functions and disrupt physiological homeostasis.Therefore, it is very important to monitor heavy metals in aquatic ecosystems.In this study, we developed new methods to detect heavy metals and it includes the following two parts of experiments:1. Detection of Copper(Cu²⁺)Cu²⁺ is an essential element required as a cofactor and/or structural component of numerous enzymes and other proteins needed in metabolic processes. However, high level of copper have adverse health consequences such as stomach and intestinal distress, liver or kidney damage, as well as loss of cognition in aging population, and complications of Wilson's disease.1-2 The U.S. Environmental Protection Agency (EPA) set 1.25 ppm (20μM) as the maximum contamination concentration for Cu²⁺ in drinking water.A lateral flow nucleic acid biosensor(LFNAB) based on copper-dependent DNA-cleaving DNAzyme and gold nanoparticles has been developed for the detection of copper ions (Cu²⁺) in aqueous solution with high sensitivity and selectivity. The sensor allows rapid and accurate detection of as low as 10 nM of Cu²⁺ within 20 minutes by naked eye.2. Detection of Lead(Pb²⁺)Pb²⁺ is one of the most toxic metallic pollutants, and it may cause gastrointestinal disturbance and liver or kidney damages as well as neurological damage at high concentrations.The U.S. Environmental Protection Agency (EPA) sets 15 ppb (72 nM) as the maximum concentration of Pb²⁺ in drinking water. Regular testing of water is increasingly preferred and self-test performed by persons who are exposed to Pb²⁺ pollution may be an integral part of the future health care systems.We developed a LFNAB for the detection of Pb²⁺ based on competitive chromatographic lateral flow assay and nucleic acid hybridization. This sensor allowed a rapid detection of 500 nM Pb²⁺ in water or 1μM Pb²⁺ in urine by naked eyes using Pb²⁺-dependent DNA-cleaving DNAzyme.Therefore, the LFNAB is easy to use,and doesn't require trained personnel and complex and expensive intruments. The LFNAB coupled with a portable strip reader shows great promise for in-field quantitative testing, it can be used in remote areas where diagnostic facilities are limited. It also serves as an alternative means of Cu²⁺/Pb²⁺ test to existing laboratory test, facilitating the implement of appropriate Cu²⁺/Pb²⁺ contamination monitor.