Reversion of gold nanoparticle aggregates for the detection of Cu2+ and its application in immunoassays
Journal
Analyst
Journal Volume
142
Journal Issue
24
Pages
4684-4690
Date Issued
2017
Author(s)
Abstract
A high concentration of copper is a hazardous element to organisms and human health. Although various strategies have been reported for the sensitive detection of copper, a facile and rapid detection of aqueous copper has seldom been addressed to date. Here, we present an easy and accessible colorimetric method to detect Cu2+ using the redispersion of cysteamine-modified gold nanoparticles (CA-AuNPs). Initially, CA caused the aggregation of AuNPs due to the electrostatic interaction and aggregated AuNPs can be regenerated in basic medium. The subsequent addition of Cu2+ to the CA-AuNP dispersion could effectively trigger the aggregation of CA-AuNPs, resulting from the coordination reactivity between the deprotonated CA and Cu2+. This strategy resulted in a detection limit (LOD) of 1.52 μM in drinking water, which is below the U.S. Environmental Protection Agency permissible limit (20 μM). To demonstrate the broad application of CA-AuNPs, we further applied this method to plasmonic immunoassays based on the competitive interaction of Cu2+ between CA-AuNPs and enzymes. The LOD of the Down syndrome biomarker hyperglycosylated human chorionic gonadotropin (H-hCG) was 0.125 mIU mL-1, which is better than that of commercial immunoassays. Importantly, the determination of H-hCG in serum indicates its applicability for the measurement of real samples. Our assay agrees well with the current immunoassay systems and thus it can easily be expanded to a more common sensing platform for different types of biotargets by changing the corresponding antibodies. ? This journal is The Royal Society of Chemistry.
Other Subjects
chorionic gonadotropin; copper; drinking water; gold; metal nanoparticle; adult; colorimetry; enzyme linked immunosorbent assay; female; genetic procedures; human; immunoassay; limit of detection; male; pregnancy; urinalysis; Adult; Biosensing Techniques; Chorionic Gonadotropin; Colorimetry; Copper; Drinking Water; Enzyme-Linked Immunosorbent Assay; Female; Gold; Humans; Immunoassay; Limit of Detection; Male; Metal Nanoparticles; Pregnancy; Urinalysis
Publisher
Royal Society of Chemistry
Type
journal article