High Peroxidase-Mimicking Metal–Organic Frameworks Decorated with Platinum Nanozymes for the Colorimetric Detection of Acetylcholine Chloride and Organophosphorus Pesticides via Enzyme Cascade Reaction

Abstract

The sensitive detection of acetylcholinesterase (AChE) and organophosphorus pesticides (OPs) is very important for the protection of human health. Herein, a hybrid material, Pt NPs/Fe-MOF, consisting of a metal−organic framework (MIL-88B-NH 2 , Fe-MOF) decorated with platinum nanoparticles (Pt NPs), was prepared first and exhibited remarkably improved and excellent peroxidase-mimicking activity compared to the Fe-MOF material resulting from the synergistic catalysis effect between Fe-MOF and Pt NPs, which can effectively catalyze 3,3′,5,5′tetramethylbenzidine (TMB) oxidation to generate a blue product (oxidized TMB, oxTMB). Interestingly, in the presence of AChE and acetylcholinesterase, the peroxidase-mimicking activity from Pt NPs/Fe-MOF was inhibited obviously, and thus, a colorimetric sensing platform for AChE can be constructed; more importantly, after the addition of OPs, this nanozyme activity can be recovered, inducing the further successful construction of a sensitive colorimetric sensing platform for OPs. The related sensing mechanism and condition optimization were studied, and the as-prepared Pt NPs/Fe-MOF nanozyme-based colorimetric method for AChE and OP detection displayed superior analytical performances with wide linearities and low detection limits. Furthermore, the designed method offers satisfactory real application ability. We expect the as-proposed Pt NPs/Fe-MOF nanozyme-based colorimetric sensing platform for AChE and OPs via the enzyme cascade reaction to show great potential application.

Nanozymes: powerful catalytic materials for environmental pollutant detection and degradation

“…190 With low cost, excellent stability, and robust performance, nanomaterials with peroxidase- or oxidase (OXD)-like activities can be integrated with bioenzymes to fabricate natural enzyme–nanozyme cascade systems for pesticide detection. 157–163,165–177,191 Very recently, we explored an Fe-based phosphotungstate (Fe-PTs) with a notable peroxidase-like feature at neutral pH to establish a portable multi-enzyme biosensor for pesticide analysis. 176 The electrostatic interaction between positively charged TMB and negatively charged Fe-PTs as well as the promoted regeneration of Fe 2+ was supposed to play crucial roles in enabling the material to show favorable peroxidase-mimetic activity under neutral conditions.…”

Nanomaterials for Potential Detection and Remediation: A Review of Their Analytical and Environmental Applications

“…Despite the above, AChE-based biosensors can suffer from enzyme leaks and decreased sensitivity. Immobilization methods such as cross-linking, covalent bonds, or physical adsorption have been used for this purpose [74][75][76]. On the other hand, naturally occurring biopolymers are preferable for enzyme immobilization.…”

Sandwich-Like Electrochemical Immunosensing of Squamous Cell Carcinoma Antigen Based on Gold Nanoparticles/Reduced Graphene and Toluidine Blue/UIO-66-NH2

“…[24][25][26] Another key aspect for the STEM assay is to design effective signal amplifier. UIO-66-NH 2 , a porous hierarchically zirconium-based MOFs nanomaterial, has large specific areas, stable porous structure and high porosity, 27,28 which provides an ideal platform for accommodating a large number of electroactive molecules as probes; meanwhile, there are abundant of -NH 2 groups on the surface of UIO-66-NH 2 , making it easily to modify with antibody. [29][30][31][32][33] According to the previous reports, toluidine blue (Tb), a commonly used electronic probe in the fabrication of electrochemical sensors, can be adsorbed on the surface of UiO-66-NH 2 by electrostatic attraction.…”