Pt Nanoparticles with High Oxidase-Like Activity and Reusability for Detection of Ascorbic Acid

Abstract

Noble metal nanoenzymes such as Pt, Au, Pd, etc. exhibit magnificent activity. However, due to the scarce reserves and expensive prices of precious metals, it is essential to investigate their enzyme-like activity and explore the possibility of their reuse. In this work, the oxidase-like activity and reusability of several Pt nanoparticles with different morphologies were detected. We compared the Pt nanoparticles (NPs) with a size of about 30 nm self-assembled by 5 nm Pt nanoparticles and Pt nanoparticles (Pt-0 HCl) with a diameter of about 5 nm, and found that their Michaelis−Menten constants (Km) were close and their initial performance similar, but the Pt NPs had better reusability. This was probably attributed to the stacked structure of Pt NPs, which was conducive to the substance transport and sufficient contact. At the same time, it was found that the size, dispersion, and organic substances adsorbed on the surface of Pt nanoparticles would have a significant impact on their reusability. A colorimetric detection method was designed using the oxidase-like activity of Pt NPs to detect ascorbic acid in triplicate. The limits of detection were 131 ± 15, 144 ± 14, and 152 ± 9 nM, with little difference. This research not only showed that the morphology of the catalyst could be changed and its catalytic performance could be controlled by a simple liquid phase synthesis method, but also that it had great significance for the reuse of Pt nanoenzymes in the field of bioanalysis.

Au/N-Doped Carbon Dot Nanozymes as Light-Controlled Anti- and Pro-Oxidants

“…The pH value varied from 1.68 to 10.0, and the optimal pH is around 3.5. The effect of pH on the light-triggering oxidase-like activity is similar to natural enzymes and previously reported nanozymes with oxidase and peroxidase-like activity. − The pH-dependent catalytic activity is mainly due to the diamine structure of TMB showing poor solubility in a weak base medium . In addition, the degree of TMB oxidation is increased with extending the irradiation time.…”

Gold-Platinum Nanoparticles with Core-Shell Configuration as Efficient Oxidase-like Nanosensors for Glutathione Detection

“…Firstly, we optimized the pH buffer to reach the maximum signal-to-noise ratio ( Figure 3 b). We obtained the maximum oxidase-like activity at a pH of 4, a typical trend observed for noble-metal based (Au [ 7 ] or Pt [ 27 , 28 , 29 ]) or transition-metal (Mn [ 60 , 61 ], Ce [ 2 ], Ni-Co [ 62 ] or Mn-Fe [ 51 ] mixed oxides) oxidase-like nanozymes. Then, the following experiments were carried out using a buffer at pH = 4.00.…”

“…However, this -SH group is susceptible to poison the surface of noble-metal based nanozymes, blocking its catalytic activity. This behavior has been also used to detect other analytes, such as ascorbic acid [ 27 , 28 ] or dopamine [ 29 ].…”

Fiber-in-Tube Design of a CuFe2O4@Conducting Polymer with Synergistically Enhanced Peroxidase-like Activity for Total Antioxidant Capacity Assays

“…During the past few years, a mass of functional nanomaterials such as precious metals, metal oxides, metal sulfides, nanocarbons, metal–organic frameworks, and inorganic–organic nanohybrids have been demonstrated to possess peroxidase-like activities. − However, their catalytic activities are still significantly lower than that of natural enzymes, and there is still a lot of space for promoting the enzyme-like efficiency of those nanozymes. Recently, several strategies have been utilized to promote the enzyme-like catalytic performance of nanozymes, including the regulation of their size and morphology, modulation of the electronic structure by doping with heteroatoms and interfacial engineering, and ligand modification. − Recently, confinement catalysis has been of particular interest due to its dramatically enhanced catalytic efficiency with up to an order of magnitude . Generally, the active components confined in a hollow structure can affect their electronic states by the coordination environment, thus optimizing the adsorption energy of the catalytic intermediates and resulting in an enhanced catalytic efficiency and selectivity .…”