Detection Efficiency of Ag Nanoparticle Labels for a Heart Failure Marker Using Linear and Square-Wave Anodic Stripping Voltammetry

In this article, we compare linear sweep anodic stripping voltammetry (LASV) and square-wave anodic stripping voltammetry (SWASV) for detection of a nano metalloimmunoassay. Two separate immunoassays were examined: a model assay, based on interactions between antibodies, and a sandwich assay for the heart failure marker NT-proBNP. In both cases, one antibody is linked to a magnetic microbead, and one is linked to a spherical Ag nanoparticle label. Electrochemical detection is carried out on a paper device. The three analytical figures of merit studied were the precision of the measurements, the calibration sensitivity, and the limit of detection (LOD). For the NT-proBNP assay, the results show that after optimization of the pulse amplitude and frequency of the potential input for SWASV, the detection efficiency is substantially higher compared to LASV. Specifically, the calibration sensitivity increased by up to similar to 40 fold, the average coefficient of variation decreased by similar to 40%, and the (LOD) decreased to 300.0 pM. Finally, for a model immunoassay, a similar to 10-fold decrease in the LOD was observed for SWASV compared to LASV.

Automated summary

In this article, the application of linear sweep anodic stripping voltammetry (LASV) and square-wave anodic stripping voltammetry (SWASV) for detection of a nano metalloimmunoassay is compared. The results show that SWASV can significantly improve the detection efficiency and demonstrate better performance in terms of calibration sensitivity and limit of detection.