Scanometric nanomolar lead (II) detection using DNA-functionalized gold nanoparticles and silver stain enhancement

Based on gold label silver stain method, a facile, sensitive and selective scanometric method for the detection of lead (II) was developed. The main components of the method include "8-17" DNAzyme functionalized gold nanoparticles (AuNPi), capture DNA functionalized gold nanoparticles (AuNP2), and silver staining. In presence of lead (II), AuNPi was cleaved into different pieces that were captured by AuNP2; and became aggregated and formed network structures. These aggregate structures hindered the exposure of gold particles during the silver staining, resulting in a reduced gray values compared with that in the absence of lead (II). Using the gray value of silver stain signals, the developed scanometric assay realized a semi-quantitative detection of nanomolar levels of lead (II), ranging from 2 to 1000 nmol/L (about 0.4-200 ppb), without significant interference from other metal ions. Results suggested that this scanometric method is a simple, sensitive, selective, and portable tool for the onsite detection of nanomolar levels of lead (II). (C) 2014 Elsevier BM. All rights reserved.