Aggregation
of Individual Sensing Units for Signal
Accumulation: Conversion of Liquid-Phase Colorimetric Assay into Enhanced
Surface-Tethered Electrochemical Analysis
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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<sup>2+</sup> determination. Through a specific T-Hg<sup>2+</sup>-T coordination,
the validation system based on functionalized sensing units not only
can perform well in a colorimetric Hg<sup>2+</sup> assay, but also
can be developed into a more sensitive and stable electrochemical
Hg<sup>2+</sup> 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