Ni-Cu-Zn Prussian Blue Analogue Nanozyme-Based Cascade Colorimetric Platform for Glucose Detection.

The development of stable and efficient artificial enzymes has attracted significant interest for biosensing applications due to the limitations associated with natural enzymes, including poor stability and sensitivity to environmental conditions. In this research, a Ni-Cu-Zn-incorporated Prussian Blue analogue (NiCuZn-PBA) nanozyme was prepared by the controlled co-precipitation method and explored as peroxidase mimicking catalyst for colorimetric glucose detection. The structure and chemical composition of the synthesized material were studied by the techniques of TEM, XRD, FTIR, Raman, UV-Vis spectroscopy, XPS and elemental mapping which showed the formation of a cyanide-bridged PBA-type structure with Ni, Cu and Zn species in the material. The nanozyme showed peroxidase-like activity as it catalized the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide to generate a characteristic oxidized TMB signal at 652 nm. A cascade colorimetric sensing platform for glucose determination was invented by combining glucose oxidase (GOx) with the PBA nanozyme. The developed sensor showed a linear response to the range of glucose concentrations from 10 to 120 µM under optimized conditions with a LoD value of 1.31 C. The sensor displayed excellent selectivity towards common interfering substances as well as satisfactory recovery values (99.03-100.80%) for synthetic urine samples. The Ni-Cu-Zn PBA sensing platform is a novel platform that can serve as an alternative with stable and low-cost ability to detect glucose using enzyme-assisted colorimetric method.