1 research outputs found
DNA-Templated Silver Nanoclusters for Fluorescence Turn-on Assay of Acetylcholinesterase Activity
We have developed a fluorescence
turn-on assay using DNA-templated
silver nanoclusters (Ag NCs) (i.e., 12 polycytosine-templated silver
nanoclusters, dC<sub>12</sub>–Ag NCs), which is amenable to
rapid, ultrasensitive assay of acetylcholinesterase (AChE). The detection
mechanism is based on the concept, that is, AChE hydrolyzes the acetylthiocholine
(ATCh) chloride to produce thiocholine (TCh). Subsequently, TCh sensitively
and rapidly reacts with dC<sub>12</sub>–Ag NCs via Ag–S
bond forming and enhances the fluorescence of dC<sub>12</sub>–Ag
NCs. Using dC<sub>12</sub>–Ag NCs, detection of TCh has a linear
concentration range of 2.0 nM to 16.0 nM and a detection limit of
0.3 nM. Due to the sensitive and rapid fluorescence turn-on response
of dC<sub>12</sub>–Ag NCs to TCh, AChE with activity as low
as 0.5 × 10<sup>–4</sup> U/mL (signal/noise = 3) can be
analyzed with a dynamic range of 0.1 to 1.25 × 10<sup>–3</sup> U/mL. The promising application of the proposed method in AChE inhibitor
screening was demonstrated. AChE concentrations were determined in
human blood red cell (RBC) membranes from clinical specimens using
dC<sub>12</sub>–Ag NCs, and the quantitative results were validated
with Ellman’s method. Aside from the ease of manufacture, reduction
of matrix effect, and low background noise, the continuous detection
format and detection sensitivity can open up to wider applications
to AChE activity assay in neurobiology, toxicology, and pharmacology,
among other fields