Layered Double Hydroxide-Derived Two-Dimensional Bimetallic Metal–Organic Framework Nanozymes for Microorganism Identification

Abstract

A lack of rapid and dependable microbial identification platforms, as well as insufficient or overdue microbiological surveillance and corresponding resolutions implemented in clinical diagnosis and treatment, agricultural production, and the food industry, can seriously harm human health and reduce productivity in the food industry. Here, a two-dimensional Ni–Co bimetallic metal–organic framework nanozyme (2D-NCM) is prepared for the rapid and efficient discrimination of microbes including clinical pathogens and brewing fungi. The nanozyme 2D-NCM, which is synthesized via a facile layered double hydroxide in situ transformation strategy, exhibits enhanced peroxidase-like activity. The biocatalytic activity of 2D-NCM could be altered to different degrees via different interactions between 2D-NCM and microbes. By selection of diverse compositions of absorbance at different time points, the sensing unit, 2D-NCM, could provide multichannel information for microbial identification. The nanozyme-based platform prevents the tedious synthesis of multiple biosensing receptors and the demand for complicated operation/precise devices, resulting in lower cost, quicker response (within 0.5 h), higher throughput, and simpler handling without washing procedures. This study provides an alternative strategy to construct practicable, facile, and flexible MOF nanozyme based biosensing arrays for the identification of microbes, making an active contribution toward precision medicine, food safety, and environmental protection.

Formulation of Antioxidant Composites by Controlled Heteroaggregation of Cerium Oxide and Manganese Oxide Nanozymes

“…These enzymes include SOD, catalase, oxidase, and peroxidase. Numerous materials of various structures and compositions have been found to mimic such enzymes including metallic nanoparticles (Ag, Au, and Pd), − metal oxides (Co 3 O 4 , CeO 2 , and V 2 O 5 ), − metal chalcogenides (FeS, MoS 2 , and WS 2 ), − clays, , carbon materials (fullerenes and carbon nanotubes), biopolymers, , and metal–organic frameworks . The surface functionalities and parameters of nanoparticles such as metal oxides often result in the aggregation of the bare and primary particles into clusters of various sizes, depending on the experimental conditions in the system such as ionic strength, the presence of polyelectrolytes, and the nature of the solvents. − In addition, many metal oxide particles are characterized by an isoelectric point (IEP), , at which the particles have no surface charge and tend to undergo heavy aggregation that results in the loss of the surface area, which could lead to a significant reduction of the enzymatic activity.…”

“…These enzymes include SOD, catalase, oxidase, and peroxidase. Numerous materials of various structures and compositions have been found to mimic such enzymes including metallic nanoparticles (Ag, Au, and Pd), 16 − 18 metal oxides (Co 3 O 4 , CeO 2 , and V 2 O 5 ), 19 − 23 metal chalcogenides (FeS, MoS 2 , and WS 2 ), 24 − 27 clays, 28 , 29 carbon materials (fullerenes and carbon nanotubes), 30 biopolymers, 31 , 32 and metal–organic frameworks. 33 The surface functionalities and parameters of nanoparticles such as metal oxides often result in the aggregation of the bare and primary particles into clusters of various sizes, depending on the experimental conditions in the system such as ionic strength, the presence of polyelectrolytes, and the nature of the solvents.…”