Sensitive Naked-eye and Fluorescence Determination of Acetylcholinesterase Activity using Cu/Ag Nanoclusters Based on Inner Filter Effect

摘要

In this work, a novel naked eye and fluorescence sensor for acetylcholinesterase (AChE) determination based on copper/ silver nanoclusters (Cu/Ag NCs) was developed. L-Histidine protected Cu/Ag NCs were prepared and exhibited superior properties compared with copper nanoclusters, with the quantum yield increased from 4.3% to 13.2%. The fluorescence of Cu/Ag NCs can be easily quenched by 2-nitro-5-thiobenzoate anion (TNB) owing to the inner filter effect. TNB is the product between 5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) and thiols. However, AChE can specially catalyze acetylthiocholine (ATCh) to hydrolyze and release biothiols (TCh). Based on this, the determination of AChE was achieved by introducing DTNB. A naked eye sensor was also constructed owing to the color change.