Metal–Organic Frameworks Enhance Biomimetic Cascade Catalysis for Biosensing

Abstract

Multiple enzymes‐induced biological cascade catalysis guides efficient and selective substrate transformations in vivo. The biomimetic cascade systems, as ingenious strategies for signal transduction and amplification, have a wide range of applications in biosensing. However, the fragile nature of enzymes greatly limits their wide applications. In this regard, metal–organic frameworks (MOFs) with porous structures, unique nano/microenvironments, and good biocompatibility have been skillfully used as carriers to immobilize enzymes for shielding them against hash surroundings and improving the catalytic efficiency. For another, nanomaterials with enzyme‐like properties and brilliant stabilities (nanozymes), have been widely applied to ameliorate the low stability of the enzymes. Inheriting the abovementioned merits of MOFs, the performances of MOFs‐immboilized nanozymes could be significantly enhanced. Furthermore, in addition to carriers, some MOFs can also serve as nanozymes, expanding their applications in cascade systems. Herein, recent advances in the fabrication of efficient MOFs‐involving enzymes/nanozymes cascade systems and biosensing applications are highlighted. Integrating diversified signal output modes, including colorimetry, electrochemistry, fluorescence, chemiluminescence, and surface‐enhanced Raman scattering, sensitive detection of various targets (including biological molecules, environmental pollutants, enzyme activities, and so on) are realized. Finally, challenges and opportunities about further constructions and applications of MOFs‐involving cascade reaction systems are briefly put forward.

Au3+‐Functionalized UiO‐67 Metal‐Organic Framework Nanoparticles: O2•− and •OH Generating Nanozymes and Their Antibacterial Functions

“…Also, organic nanoparticles, for example, melanine, [ 32 ] polyethylenimine, [ 33 ] were introduced as functional catalytic systems of mimicking enzymes. Furthermore, metal‐organic framework nanoparticles (NMOFs) modified with metal ions‐ligand units [ 34–37 ] or catalytic nanoparticles [ 38–41 ] integrated in the porous structure of the frameworks were applied as catalytic nanozymes. In addition, the chemical modification of nanozymes with receptor ligands improved their enzyme‐like activities.…”

Advances in Visual Immunoassays for Sensitive Detection of Mycotoxins in Food—A Review

“…Although natural enzymes are extensively used in various fields, their catalytic activities were still susceptible to the extreme environment, e.g., heat, pH, organic solvents, mechanical stress, heavy metal, etc. Meanwhile, they present many shortcomings, such as high expense, low recyclability, poor operational stability and limited practical applications, e.g., the preparation, reaction, and storage requirements [81][82][83]. Nanomaterials-based artificial enzymes (nanozyme) have been particularly attractive since the discovery of Fe 3 O 4 NPs with peroxidase-like activity by Yan's group in 2007 [84].…”

“…In the catalytic cascade system, the decreased diffusion path of intermediates between the enzymes enables the improvement of unstable intermediates, facilitating their efficiency and specificity [102][103][104]. Meanwhile, the single substrate can be converted into more signal molecule through the multienzyme-associated continuous catalysis reaction and contributes to the signal amplification [68,83,105]. Lai et al [105] proposed a competitive cascade amplified immunoassay for AFB 1 detection in peanut samples by a combination of ascorbate oxidase (AO x )/anti-AFB 1 antibody-labeled AuNPs and oxidase-mimics MnO 2 (Figure 3D).…”

Treatment of Acute Kidney Injury Using a Dual Enzyme Embedded Zeolitic Imidazolate Frameworks Cascade That Catalyzes In Vivo Reactive Oxygen Species Scavenging

“…In the past few decades, anchoring enzymes to the outer surface of MOF particles by chemical grafting or physical adsorption has been the primary method for entrapment of the enzymes ( Rosenkrans et al, 2020 ; Tripathy et al, 2021 ). It relied on the interaction between the organic ligand of MOFs and the surface components of enzymes ( Liu et al, 2021 ; Velásquez-Hernández et al, 2021 ; Xu et al, 2021 ). Although this method provides a certain protection against enzyme denaturation, most enzymes are still directly exposed, so immobilized enzymes are still susceptible to changes in the external environment ( Liang et al, 2021 ; Velásquez-Hernández et al, 2021 ).…”