Aggregation of Individual Sensing Units for Signal Accumulation: Conversion of Liquid-Phase Colorimetric Assay into Enhanced Surface-Tethered Electrochemical Analysis

Abstract

A novel concept is proposed for converting liquid-phase colorimetric assay into enhanced surface-tethered electrochemical analysis, which is based on the analyte-induced formation of a network architecture of metal nanoparticles (MNs). In a proof-of-concept trial, thymine-functionalized silver nanoparticle (Ag-T) is designed as the sensing unit for Hg(2+) determination. Through a specific T-Hg(2+)-T coordination, the validation system based on functionalized sensing units not only can perform well in a colorimetric Hg(2+) assay, but also can be developed into a more sensitive and stable electrochemical Hg(2+) sensor. In electrochemical analysis, the simple principle of analyte-induced aggregation of MNs can be used as a dual signal amplification strategy for significantly improving the detection sensitivity. More importantly, those numerous and diverse colorimetric assays that rely on the target-induced aggregation of MNs can be augmented to satisfy the ambitious demands of sensitive analysis by converting them into electrochemical assays via this approach.

A sensitive and selective electrochemical biosensor for the determination of beta-amyloid oligomer by inhibiting the peptide-triggered in situ assembly of silver nanoparticles

“…[47][48][49][50][51][52][53][54][55][56][57][58][59] In particular, silver nanoparticles (AgNPs) offer clear advantages for the design of electrochemical (bio) sensors, such as a simple preparation procedure, a size-dependent optical property, facile surface modification, a high surface area and a low oxidation potential. [55][56][57][58][59] Based on the specific Aβ oligomer/PrP 95-110 interaction and the well-defined and signal-amplified electrochemical signal of AgNP aggregates, Xia et al 59 have developed an electrochemical biosensor for the determination of Aβ oligomer by using adamantine …”

A Novel Electrochemical Aptamer Biosensor Based on DNAzyme Decorated Au@Ag Core-Shell Nanoparticles for Hg2+ Determination

“…Meanwhile, a variety of aptamer biosensors have been fabricated based on the chelation between Hg 2+ and thymine (T). 19,20 For example, Wei et al 21 designed thymine-functionalized silver nanoparticle (Ag-T) as the sensing unit for Hg 2+ determination and assembled individual sensing units for signal amplification. Significant progress has been made in the field of Hg 2+ determination, however, increasing sensitivity and decreasing detection limit are always the goals of scientists.…”

“…With the goal of measuring Hg 2+ , two-step incubation method was employed, which was beneficial to the bound of T-Hg 2+ -T. 32 First, the prepared DNA1/Au electrode was incubated with various concentrations of Hg 2+ for 35 min at room temperature (designed as Hg 2+ /DNA1/ Au). Following that, the Hg 2+ /DNA1/Au electrode was immersed into DNA2-Au@Ag-DNAzyme solution for another 35 min, and the double-strand DNA structure was formed based on T-Hg 2+ -T (designed as DNA2-Au@Ag-DNAzyme/Hg 2+ /DNA1/Au).…”

Electrochemical Detection of Hydrogen Peroxide by Inhibiting the p-Benzenediboronic Acid-Triggered Assembly of Citrate-Capped Au/Ag Nanoparticles on Electrode Surface

“…Thus, the colorimetric examples were expected to re-create existing platforms with improved sensitivity. By simply incorporating the colorimetric principle or technique into another field, new achievements were produced recently [14,15,16,17,18]. For example, based on the high quenching efficiency of dispersed but not aggregated Au NPs on the fluorescence of organic dyes or quantum dots (denoted as the efficient inner filter effect), visual and fluorescent sensors could be developed [14,15,16].…”