Stabilizing Ultrasmall Ceria‐Cluster Nanozyme for Antibacterial and Antibiofouling Applications

Abstract

haloperoxidases. [15,16] This kind of natural enzymes can catalyze the two-electron oxidation of halides to microbicidal hypohalous acids (HOX, X: Cl − , Br − , I − ) or analogous oxidized halide species in the presence of hydrogen peroxide (H 2 O 2 ). [17][18][19] Such natural biofilm inhibition utilizing naturally occurring reagents (halide and H 2 O 2 ) represents a promising and environmentally friendly antibiofilm strategy. Nevertheless, natural enzymes often suffer from intrinsic drawbacks such as highcost, poor operational stability, and recyclability. Artificial nanozymes, one kind of nanomaterials combining nanoscale and enzyme-like catalytic functionalities, exhibit advantages such as low-cost and high durability. [20][21][22][23][24] Interestingly, some nanomaterials (e.g., vanadium pentoxide and ceria) have been explored as haloperoxidase-mimicking nanozymes. [25][26][27][28][29] Although high catalytic activity, the carcinogenicity and mutagenicity of vanadium pentoxide could hinder their large-scale application in marine environment. As a heterogeneous metal oxide nanozyme, mixed-valency nanoceria exhibited significantly enhanced catalytic activity towards haloperoxidase-like reaction in contrast to bulk ceria, [28] highlighting that high surface-to-volume ratio and surface geometric effect could strongly affect the activity of a nanozyme. Nevertheless, the haloperoxidase-like performance of nanoceria is relatively low. From a structural perspective, downsizing ceria to nanocluster scale is of significance for maximizing active component utilization and achieving better haloperoxidase-mimicking performance. Unfortunately, most nanomaterials have large particles owing to the natural tendency of agglomeration.Nanostructured materials involving highly dispersed subnanocluster species on supports have been shown to be crucial for enabling heterogeneous catalysts with high intrinsic activity and unexpected selectivity. [30][31][32][33] Nevertheless, stabilizing goaloriented high-density ultrasmall nanoclusters on solid substrates with uniform size and dispersion has been challenged by the thermodynamic instability of nanocluster, poor interfacial hybrid interaction, as well as chemical synthesis. [34][35][36] Herein we propose a fabrication strategy to fabricate hybrid CeO 2 @ ZrO 2 where high-density ultrasmall ceria clusters (≈0.8 nm) are stabilized on zirconia substrates. This unique feature of heterografting CeO 2 @ZrO 2 nanozyme enabled superior and stable haloperoxidase-mimicking performance in selectively catalyzing the oxidation of bromide with H 2 O 2 to hypobromousThe generation of undesired biofouling in medical and engineering applications results in a reduction in function and durability. Copying functionalities of natural enzymes to combat biofouling by artificial nanomaterials is highly attractive but still challenged by the inferior catalytic activity and specificity principally because of low densities of active sites. Here, an innovate strategy is demonstrated to stabilize high-density ...

Fully‐Exposed Pd Cluster Catalyst: An Excellent Catalytic Antibacterial Nanomaterial

“…The Pd n /ND@G nanozyme can convert oxygen into hydroxyl radicals (•OH) under acidic conditions, thereby causing bacteria to produce oxidative stress and death. [27][28][29][30] The results of antibacterial experiments indicate that the Pd n /ND@G nanozyme has stronger antibacterial activity compared with palladium single-atom nanozymes (Pd 1 /ND@G) and palladium nanoparticles nanozymes (Pd-NPs/ND@G). This study develops a novel fully-exposed metal cluster nanozyme and serves as the basis for the future design of novel oxidase mimics with excellent catalytic antibacterial properties.…”

Photothermal‐Amplified Single Atom Nanozyme for Biofouling Control in Seawater

“…[4,5] These metalloproteins are thought to exert a critical role in the marine biosynthesis of many halogenated organic products and could thus serve as the chemical defense system of marine organisms to fight against biofouling in seawater. [6,7] Traditional antibiofouling strategies based on releasing toxic chemical substances into marine environments, especially heavy metal biocides, are becoming a problem due to the nonselective lethal toxicity. [8][9][10] The sticker evaluation and regulations have promoted researchers to find ecofriendly anti-biofouling solutions.…”

“…[11][12][13][14] Artificial enzyme mimics featuring stable chemical structures have been proposed as potential alternatives for natural enzymes. [7,15] Nanozymes, enzyme-like catalytic nanomaterials that follow enzymatic kinetics under physiologically relevant conditions, have been explored to imitate protein enzymes in biomimetic chemistry in recent years because of their high efficiency, adjustable activity, easy scalability, and recyclability. [16][17][18] Although HPO mimics show significant research prospects, their development is still very slow with limited successful cases at present.…”

Superhydrophobic Mechano-Bactericidal Surface with Photodynamic Antibacterial Capability

“…Thus, there is a strong need to develop antibacterial surfaces so as to mitigate the challenge of bacterial contamination. Most traditional antibacterial methods involve the incorporation of biocidal agents, such as antibiotics, , metallic nanoparticles, , polycations, nanozymes, − and antimicrobial peptides, , on material surfaces. However, the overuse of antibacterial agents triggers the growing prevalence of drug-resistant bacteria, causes an imbalance in flora, and decreases immune function, which further aggravates the infection. , The dominant problem in bacterial infection is bacterial cell attachment to various surfaces, which ultimately forms biofilms through a series of complex processes.…”