Visual monitoring of lead exposure in children’s daily activities with an AuNP-based indicator

Abstract

Lead exposure causes great harm to the growth and development of infants. A simple and fast approach that can be conveniently used at home is thus needed for parents to screen the potential lead sources in their children’s daily activities. Here, we developed a simple, fast, and sensitive gold nanoparticles (AuNPs)-based indicator for colorimetric Pb2+ detection. The method rationale was based on the higher affinity of Pb2+ to T30695 DNA over thioflavin T (ThT), as well as the stable and fast charge neutralization-induced assembly of AuNPs by ThT. To facilitate in-home monitoring, we arranged the reagents (AuNPs, DNA, ThT, and the buffer) and the required facilities (microplate and pipe) into a kit. Besides, the color change of the indicator AuNPs was monitored with a cell phone camera and processed with a self-developed APP. For samples closely related to children's daily activities, Pb2+ was successfully detected in saliva, sweat (simulated) and stomach fluid (simulated) extractions of water bottles, small benches, cushions, paint, lipstick, building blocks and toys. Therefore, continuous efforts are required for a lead-free life and such a kit can help the screening of lead-leaking clothing, food, shelter and toys for children.