Enhanced Peroxidase‐Like Performance of Gold Nanoparticles by Hot Electrons

Abstract

Enzyme mimics have been widely used as alternatives to natural enzymes. However, the catalytic performances of enzyme mimics are often decreased due to different spatial structures or absence of functional groups compared to natural enzymes. Here, we report a highly efficient enzyme-like catalytic performance of gold nanoparticles (AuNPs) by visible-light stimulation. The enzyme-like reaction is evaluated by the catalytic reaction of AuNPs oxidizing a typical chromogenic substrate 3,3',5,5'-tetramethylbenzydine (TMB) with hydrogen peroxide as an oxidant. From investigations of the wavelength-dependent reaction rate, radical capture, hole-donor addition, and dark-field scattering spectroscopy experiments, it is revealed that the strong plasmonic absorption of AuNPs facilitates generation of hot electrons, which are transfered from AuNPs to the adsorbed reactant molecule, greatly promoting the catalytic performance of the enzyme-like catalytic reaction. The present work provides a simple method for improving the performance of enzyme mimics, which is expected to find further application in the field of plasmon-enhanced biocatalysis and biosensors.

Fluorescein as a Visible‐Light‐Induced Oxidase Mimic for Signal‐Amplified Colorimetric Assay of Carboxylesterase by an Enzymatic Cascade Reaction

“…horseradish peroxidase, HRP), such as high cost in large‐scale production, poor stability of catalytic activities against denaturation, digestion, or the variations of environmental conditions, researchers have, therefore, endeavoured to develop artificial enzymes, such as nanozymes, metal‐organic frameworks, and small‐molecule‐based mimic peroxidises, as viable alternatives. Although these artificial peroxidases exhibit some advantages over HRP, for example, low in cost, easy to prepare, high stability, and so on, most of them need destructive and unstable H 2 O 2 as an oxidant to obtain high catalytic activity, which may become an obstacle to further applications. More significantly, owing to a lack of simple, green, and cost‐effective means to modulate the catalytic activity of nanozymes, it is highly desirable to exploit a new class of enzyme mimics, the activities of which can be easily modulated without the aid of H 2 O 2 .…”

The Role of Onium Salts in the Pro‐Oxidant Effect of Gold Nanoparticles in Lipophilic Environments

“…In analogy, the R i values recorded for reactions occurring in the dark or under ambient light were the same. Reasonably, an enhancement of the peroxidase activity of the AuNPs only occurs with intense illumination by lamps or lasers . On the contrary, replacing t BuOOH with di‐ tert ‐butylperoxide, which is a known radical initiator, having the peroxide moiety but lacking the OH group, the reaction did not occur.…”

“…radicals in water at pH<4 when mixed to H 2 O 2 , whereas citrate‐capped AuNPs had a negligible effect when tested under similar conditions . The peroxidase activity of citrate‐capped AuNPs was instead boosted by light stimulation in the plasmonic absorption band . When supported on nanodiamonds, bare AuNPs acted as potent catalyst for the radical production, and this reaction was enhanced by a λ =532 nm laser pulse .…”

“…[22] The peroxidase activity of citrate-capped AuNPs was instead boosted by light stimulation in the plasmonic absorption band. [23] When supported on nanodiamonds, bare AuNPs acted as potent catalystf or the radicalp roduction, [24] and this reaction was enhanced by a l = 532 nm laser pulse. [25] Moreover,A uNPs protected by weakly bound ligands (e.g.,p hosphines and amines) initiated the air oxidation of organic substrates even in the absence of added hydroperoxides, whereas AuNPs protected by thiols were inactive under the same conditions.…”

Enhanced Electrocatalysis via Boosted Separation of Hot Charge Carriers of Plasmonic Gold Nanoparticles Deposited on Reduced Graphene Oxide

“…[1][2][3][4] The LSPR of plasmonic nanostructures can be visualized as an electromagnetic field coupled to the coherent oscillation of all conduction electrons. [10][11][12][13][14][15] Recently growing interests have been paid on the plasmonic nanostructures for both the fundamental studies and technological applications. [5] Moreover, by engineering the particle size, shape, material, and environment, the optical properties of the plasmonic nanomaterials can be tunable correspondingly.…”