Recent Advances in Silver nanozymes: Concept, Mechanism, and Applications in Detection

Abstract

physicochemical properties that are entirely different from those of their bulk counterparts. They have been exploited vigorously for numerous applications, including in medical and nonmedical fields. However, one must not realize it to be a novel technology, as its roots can be traced centuries ago. For instance, copper and silver (Ag) NPs can be dated back to the 9 th century, when they were used to shine the ceramic artifacts. [1] One of the earlier and renowned examples is the Lycurgus cup, made by the Romans in the 4 th century using Au-Ag alloy NPs to produce greenish-red color. [2] Even though the use of NPs could be found in many such old works of literature; their real potential was not completely understood until 1959, when Richard Feynman delivered the renowned lecture "There's Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics. [3] This brought in a stream of exceptional studies, and researchers were able to assign quantum size effects as the reason for a change of properties when moving from bulk to nano regime. As things became more and more precise, nanomaterials began to find their extensive role in varied applications. One of the significant applications was their role as enzyme mimetics due to their excellent catalytic properties.The metabolic reactions in our body are catalyzed by the protein molecules called enzymes. It was James B Sumner who, in 1926, established the first enzyme, urease, to be a protein, which won him a Nobel Prize for this discovery in 1946. [4] All the enzymes have been considered protein molecules ever since. However, due to their high production cost and rapid denaturation under variable pH and temperature settings, they have limited their industrial applications. [5] Therefore, a need was felt to develop enzyme mimicking materials, more precisely termed "artificial enzymes" by Robert Breslow. [6] These catalytically active molecules can be anything from polymers, cyclodextrins to supramolecules and dendrimers, showing enzyme-like activity. [7][8][9][10] Recently, the discovery of dismutaselike activity of fullerene derivatives [11,12] and peroxidase-mimicking catalysis of Fe 3 O 4 NPs [13,14] enunciated the promising career of NPs in the field of biomimetics. The importance and broad prospect of nanozymes can be understood in Figure 1. This shows the increasing number of publications each year on nanozymes. These nanozymes have been majorly used Natural enzymes accelerate substrate-specific reactions making them of exquisite interest for various applications. However, their appeal is lost in a practical setting due to low stability and high preparation expenses. This is the primary reason behind the flourishing in the research of nanozyme, i.e., artificial enzymes, in the past decade. Their unique physicochemical properties make them a promising candidate for various applications, especially in diagnostics and detection. They possess an enzyme-like activity and can overcome the drawbacks of natural protein-based enzymes. Nanozymes are nanomateri...

Silver Nanoparticle-Immobilized Schiff-Base Macrocycles as Nanozymes with Peroxidase Mimic Activity for Antibacterial Films

“…To avoid the waste of the precious metal and the agglomeration of nanoparticles, it is reasonable to design silver-based hybrid materials on substrates such as graphdiyne, g-C 3 N 4 , , rGO, , and MOFs, which also facilitates optimal antimicrobial activity against pathogenic bacteria and good biocompatibility with the human body. However, nanozymes based on Ag NPs have not been studied much due to their quick dissolution and instability . Therefore, it is of vital importance to explore potential substrate materials suitable for the growth of Ag NPs.…”

Nanozymes from Cu(II) Metal–Organic Gel and Melamine for Highly Active Peroxidase-Like Activity to Detect Alkaline Phosphatase

“…Nanozymes, a booming and promising inorganic functional nanomaterial possessing specific enzyme-like performances, have been widely used in biological analysis, disease treatment, as well as environmental governance. − Owing to its fine catalytic activity, simple preparation, low cost, and storage stability, now nanozymes tend to be a necessary substitute for natural enzymes in practical applications. , Many enzyme-like nanomaterials in previous reports were proven to have peroxide-like activity, which can catalyze colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to an oxidation blue product oxTMB in the presence of H 2 O 2 , including noble metal nanoparticles, metallic oxides, carbon-based nanomaterials, as well as metal–organic framework (MOF)-based nanomaterials. − However, the characteristics of these nanozymes usually exhibit low catalytic activity, poor selectivity, and complex preparation, which severely restrict their further use in colorimetric sensors . Hence, it is badly in need of developing a novel peroxide-like nanozyme with excellent catalytic activity, efficient recognition, and simple preparation for practical colorimetric analysis.…”

Palladium Nanoparticles Grafted onto Phytochemical Functionalized Biochar: A Sustainable Nanozyme for Colorimetric Sensing of Glucose and Glutathione

“…The generation of colored products during the oxidation assists in the estimation of the H 2 O 2 colorimetrically making the sensing process simplified. Additionally, the nanozyme property of the NPs can be extended to the detection and quantification of other organic compounds, biological molecules, and heavy metals [ 23 ].…”