title: DNA-templated silver nanoclusters for fluorescence turn-on assay of acetylcholinesterase activity.
abstract: We have developed a fluorescence turn-on assay using DNA-templated silver nanoclusters (Ag NCs) (i.e., 12 polycytosine-templated silver nanoclusters, dC12-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 dC12-Ag NCs via Ag-S bond forming and enhances the fluorescence of dC12-Ag NCs. Using dC12-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 dC12-Ag NCs to TCh, AChE with activity as low as 0.5 × 10(-4) U/mL (signal/noise = 3) can be analyzed with a dynamic range of 0.1 to 1.25 × 10(-3) 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 dC12-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.
authors.affiliation: Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China. ydzhang@snnu.edu.cn
authors.forename: Yaodong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yanan
authors.initials: Y
authors.lastname: Cai
authors.forename: Zongli
authors.initials: Z
authors.lastname: Qi
authors.forename: Lu
authors.initials: L
authors.lastname: Lu
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Qian
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis*; D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D004593:Electrophorus; D004789:Enzyme Activation; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D012834:Silver; D004247:DNA; D000110:Acetylcholinesterase