A Portable Nanozyme-Strip Fabricated by Ru-ZIF-8 with Dual Nanozymatic Activity for Detection of Acetylcholine

Graphical A Ru-ZIF-8 nanozyme with both esterase like and peroxidase like activities were prepared for acetylcholine (ACh) detection. On the basis of the Ru-ZIF-8 nanozyme, a portable nanozyme strip was developed as a novel biosensor for detecting ACh, which was conducive to promoting the development of multiple enzyme cascade assays. In the present study, the incorporation of Ru into the framework of ZIF-8 resulted in that a Ru-ZIF-8 nanozyme with both esterase-like activity and peroxidase-like activity. Owing to the dual nanozymatic activities of Ru-ZIF-8 nanozyme, the acetylcholine (ACh) detection process utilized only one natural enzyme (choline oxidase), which greatly simplified the detection procedure. In the detection process, nanozyme Ru-ZIF-8 showed esterase-like activity to catalyze the hydrolysis of ACh to choline. Then the generated choline was oxidized by choline oxidase to generate H 2 O 2 . Finally, Ru-ZIF-8 with peroxidase-like activity was used to catalyze H 2 O 2 to oxidize 2,2′-azino-bis (3-ethylbenzothiazo-line-6-sulfonic acid) ammonium salt with a color change. As a result, the linear range for ACh was from 0.01 μM-22 μM with the detection limit (DL) of 5.5 nM. In addition, Ru-ZIF-8 was utilized to fabricate a portable detection test strip. Our work provided a simple, portable, low-cost, highly sensitive and selective assay for the detection of ACh, which paved the way for the development of multi enzyme cascade assays.