Recent advances in the application of noble metal nanoparticles in colorimetric sensors for lead ions

Abstract

Recent developments in nanotechnology and engineering have produced a plethora of nanomaterials with amazing physical/chemical properties and enhanced sensing potential for various heavy metals in the environment. Noble metal nanoparticles (NPs), particularly those made from gold and silver, have attracted a great deal of attention mainly due to ease of synthesis, a high degree of surface functionalization, biocompatibility, and tunable physico-chemical properties. The use of noble metal nanoparticles has enabled fast and multiplexed detection of metal ions with excellent sensitivity and selectivity. The optical characteristics of Au-Ag NPs and noble metal-based nanozymes enable the detection of metals based on colorimetry. Color changes of these metal nanoparticles upon interaction with lead ions are based on inter-particle interactions (aggregation/dis-aggregation) and changes in surface modification. This review presents up-to-date information on the applications of noble metal NPs in the colorimetric sensing of lead (Pb2+) ions with special attention on selectivity, sensitivity, and practicality. The extensive potential of noble metal nanomaterials as the next-generation and on-site sensing tools has been explored for the rapid detection of lead ions in environmental matrices.