Electrochemical Dissolution of Silver Nanoparticles and Its Application in Metalloimmunoassay

Abstract

This work demonstrates the use of silver nanoparticles as a simple electrochemical biolabel to induce 10 6 signal enhancement. We propose a mechanism of measuring the silver nanoparticles on a specific screen-printed planar carbon electrode, without the requirement for the harsh oxidant or toxic reagents described in prior-art for gold sol methods. The possible measurement process was validated with orthogonal techniques such as UV/Vis spectroscopy, dynamic light scattering and by anodic stripping voltammetry (ASV). The findings were utilized to develop a novel electrochemical sandwich immunoassay where the analyte concentration is directly proportional to ASV oxidation peak of silver. This technique in the future is envisaged to form the foundation of a generic Point of Care platform. The assay was applied to cardiac marker: myoglobin with detection limit of 3 ng/mL.

An electrochemical immunosensing method based on silver nanoparticles

“…AgNPs could be oxidized to silver ions and then electrochemically deposited on SPEs by applying a negative potential of À0.8 V. In this case, the silver ions could permeate into the electrode surface and produce amplified detectable current signals. This phenomenon was similar to the reported work previously [13].…”

“…Direct oxidation measurement can also be applied to multiplexed target detection and make the assay rapidity. Compared to the reported immunoassay method based on silver nanoparticles [13], present current method could provide a lower detection limit with fewer steps. Thus, direct electrochemical stripping method based on AgNPs could provide more sensitive, rapid and simple analytical procedure.…”

“…Silver nanoparticles reduced from metal ions could be stabilized by anionic ligands and negatively charged. In this case, the adsorption of proteins to nanoparticles would be achieved by adjusting pH to make proteins positively charged [13,21,22]. However, physically adsorbed biomolecules are readily lost from the surface, and adsorbed proteins are often prone to be denaturized and thereby lose their biocatalytic or biorecognition activities [23].…”

“…Wang et al exploited the DNA-induced generation of metal clusters for developing an electrical biosensing method [12]. Szymanski et al reported the first immunoassay utilizing silver nanoparticles for protein detection in 2010, in which silver colloid aggregates can be transferred from 96-well Plate onto SPEs and electrochemically assayed with detection limit of 3 ng/mL [13]. The sensitivity of metalloimmunoassays can be enhanced by deposition of metal on the surface of nanoparticles, which lead to generation of more metal ions for amplifying the signal.…”

Size Dependant Electrochemical Behavior of Silver Nanoparticles with Sizes of 10, 20, 40, 80 and 107 nm

“…Here we investigate inherent electrochemistry of silver nanoparticles of sizes 10, 40, 80 and 107 nm by means of cyclic voltammetry.Keywords: Silver nanoparticles, Size dependant electrochemical behavior DOI: 10.1002/elan.201100690 There is a high demand for facile direct detection of metallic nanoparticles (NPs) arising from various areas such as biosensing [1][2][3], water quality assessment [4] or toxicity studies [5,6]. Electrochemistry is a facile method for direct determination of a wide range of metal nanoparticles, for example gold [7,8], platinum [9], silver [10][11][12] or molybdenum [13].…”