Nanozymes: Classification, Catalytic Mechanisms, Activity Regulation, and Applications

Abstract

Because of the high catalytic activities and substrate specificity, natural enzymes have been widely used in industrial, medical, and biological fields, etc. Although promising, they often suffer from intrinsic shortcomings such as high cost, low operational stability, and difficulties of recycling. To overcome these shortcomings, researchers have been devoted to the exploration of artificial enzyme mimics for a long time. Since the discovery of ferromagnetic nanoparticles with intrinsic horseradish peroxidase-like activity in 2007, a large amount of studies on nanozymes have been constantly emerging in the next decade. Nanozymes are one kind of nanomaterials with enzymatic catalytic properties. Compared with natural enzymes, nanozymes have the advantages such as low cost, high stability and durability, which have been widely used in industrial, medical, and biological fields. A thorough understanding of the possible catalytic mechanisms will contribute to the development of novel and high-efficient nanozymes, and the rational regulations of the activities of nanozymes are of great significance. In this review, we systematically introduce the classification, catalytic mechanism, activity regulation as well as recent research progress of nanozymes in the field of biosensing, environmental protection, and disease treatments, etc. in the past years. We also propose the current challenges of nanozymes as well as their future research focus. We anticipate this review may be of significance for the field to understand the properties of nanozymes and the development of novel nanomaterials with enzyme mimicking activities.

Development of Nanozymes for Food Quality and Safety Detection: Principles and Recent Applications

“…), and many other emerging materials such as metal organic frameworks (MOFs), covalent organic frameworks (COFs), metal chalcogenides, and nanohybrids. The large community of nanozymes, which is much more diverse than that of traditional enzyme analogues, endows a solid foundation of practical‐oriented explorations of nanozymes (Huang, Ren, & Qu, ; Wu, Wang et al., ). Accordingly, recent years have witnessed a booming applicability of such abundant and talented nanozymes in the agrifood industry, predominantly for detection applications.…”

An Enzyme‐Mimicking Single‐Atom Catalyst as an Efficient Multiple Reactive Oxygen and Nitrogen Species Scavenger for Sepsis Management

“…Alternatively, antioxidative nanomaterials have emerged as potential candidates in reducing intracellular RONS . Especially, nanozymes, nanomaterials with enzyme‐like characteristics, have successfully mimicked the antioxidative enzymes of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), reducing O 2 .− , H 2 O 2 , and . OH in representative inflammation .…”

“…[7] Alternatively,a ntioxidative nanomaterials have emerged as potential candidates in reducing intracellular RONS. [12][13][14][15][16][17][18][19][20] Especially,n anozymes,n anomaterials with enzyme-like characteristics, [21][22][23] have successfully mimicked the antioxidative enzymes of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), reducing O 2 C À ,H 2 O 2 ,a nd COH in representative inflammation. [13,[17][18][19][20] However,t hey are almost invalid to obliterate CNO,f rustrating to relieve systemic inflammation, given that CNO plays ac rucial role in the sepsis cascade.M oreover,t heir low antioxidative activities are insufficient to scavenge the elevated RONS levels.E ven though cerium oxide and melanin nanoparticles have displayed multi-antioxidative ability against RONS, [12,19] their activities are relatively poor and closely dependent on their sizes.T hus,i tr emains challenging to explore an ideal antioxidant that can robust scavenge multiple RONS in high efficacy.…”

Reversing Chemoselectivity: Simultaneous Positive and Negative Catalysis by Chemically Equivalent Rims of a Cucurbit[7]uril Host

“…[3] Among these are simple macrocyclic compounds, [4] more complicated molecular cages [5] or capsules, [6] and even nanoparticles. [7] These mimics,unlike enzymes, usually have afew active sites,which are often similar, and no more than one reaction can be either promoted or inhibited by them simultaneously. Cucurbiturils (CBs)b elong to af amily of primitive, macrocyclic enzyme mimics,i nw hich ah ydrophobic cavity is enclosed by two catalytically active sites of circular shape (rims) that are chemically indistinguishable ( Figure 1).…”

“…Concurrently,w ec ame across the reports of several research groups, [9] who noted that azobenzene derivatives have their azo parts hidden inside the macrocyclic cavities upon complexation with CB macrocycles.Thus,weattempted to mask the azo moiety from nucleophilic attack by hydrazine in this manner [10] and redirect the reaction toward the formation of the desired hydrazone,p rovided that the aldehyde groups would not be shielded as well. Indeed, after addition of two equivalents of cucurbit [7]uril (CB7), the most water-soluble CB host with as izable cavity volume, [11]…”