Porphyrin-Modified NiS₂ Nanoparticles Anchored on Graphene for the Specific Determination of Cholesterol

Abstract

Exploring peroxidase-like nanozymes with high catalytic activity is an urgent task to construct a fast, convenient, and selective colorimetric sensing platform. In this work, a nanozyme, 5,10,15,20-tetrakis(4-carboxyl phenyl)porphyrin-functionalized NiS 2 nanoparticles, anchored on the surface of graphene (Por-NiS 2 /GO) was designed. Compared with NiS 2 nanoparticles anchored on the surface of graphene (NiS 2 /GO), Por-NiS 2 /GO had a higher peroxidase-like activity due to the introduction of porphyrin. The size of NiS 2 nanoparticles was about 110−250 nm. The peroxidase-like behaviors of Por-NiS 2 /GO were evaluated using the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) with a fast-blue color change in less than 1 min. Electron spin resonance (ESR) data revealed that the excellent performance of Por-NiS 2 / GO was due to the active oxygen species produced, including hydroxyl radical ( • OH) and superoxide radical ( • O 2 − ), during the catalytic reaction, owing to the synergetic effect among different components including porphyrin, NiS 2 , and GO. Thus, based on the enhanced peroxidase-like activity of Por-NiS 2 /GO, a fast, sensitive, and selective colorimetric sensing platform of H 2 O 2 has been constructed, and furthermore, a sensing platform for cholesterol was also developed coupled with cholesterol oxidase (ChOx). The colorimetric sensing platform was validated by detecting cholesterol in serum samples.

Rational Atomic Engineering of Prussian Blue Analogues as Peroxidase Mimetics for Colorimetric Urinalysis of Uric Acid

“…Temperature is also a critical factor for the catalyzed reaction, and we observed that A 652nm was three times after the reaction at 37 °C than that at 10 °C, indicating that higher temperature leads to a larger optical response. This is because the chemical reaction is usually favored at high temperature. , We thereby adopted 37 °C for the oxidation reaction, consistent with the temperature used for the enzymatic conversion of UA by uricase (vide infra). Under the optimal conditions, we performed the calibration of H 2 O 2 , obtaining a wide linear calibration range from 1 to 500 μM, with a limit of detection (LOD) down to 0.19 μM by the three-sigma method (3σ/ k , σ is the standard deviation of the blank, k is the slope of the fitted calibration curve) (Figure S14).…”

Speciation Differences in the Surface Oxidizing Species on FeS2and NiS2: Reactivity in Hydrogen Atom Transfer and Oxygen Atom Transfer

“…In addition, organic compounds in low molecular weights, such as acetate, carbamide, ethylamine, formamide, purine, d -ribose, adenine, alanine, l -cysteine, and glycine, can be enriched on the surface of FeS 2 , which is a prerequisite for the formation of reactive substances for the origin of life . Under oxic and acidic conditions, both FeS 2 and NiS 2 nanozymes exhibit peroxidase and oxidase reactivity, which has been used for killing tumor cells at pH 4.5, colorimetric detection of glucose and cholesterol at pH 4.0, , polymerization of glutathione to antibacterial therapy at pH 6.5, and electrocatalytic production of H 2 O 2 at pH 3.5 . Under oxic and alkaline conditions, FeS 2 shows the oxidase reactivity in polymerization of aniline to oligoaniline .…”

Reusable nickel foam supported 3D hierarchical Co–Fe–Ni mixed metal oxides with peroxidase-like activity as biosensors for the colorimetric detection of H2O2

“…Recently, a class of novel nanomaterials with peroxidase-like activity, such as nanozymes, have aroused numerous attention owing to their high efficiency and outstanding stability under extreme conditions, compared to natural enzymes. 15,16 With extensive research, more and more nanomaterials exhibiting intrinsic peroxidase-like activity have been found, such as carbon-based nanomaterials, 17,18 nano-metal and metal oxides, [19][20][21][22] metal sulfide nanoparticles [23][24][25] and metal-organic frameworkbased nanomaterials. 26,27 Metal oxides are commonly more affordable, have simpler synthesis processes, and offer greater flexibility for tailored design.…”