Rapid and highly selective colorimetric detection of nitrite based on the catalytic-enhanced reaction of mimetic Au nanoparticle-CeO2 nanoparticle-graphene oxide hybrid nanozyme

Porous, Oxygen Vacancy Enhanced CeO2–x Microspheres with Efficient Enzyme-Mimetic and Photothermal Properties

“…A hybrid nanozyme, gold nanoparticle (AuNP)-cerium oxide nanoparticle (CeO 2 NP)-anchored graphene oxide (GO) was used for nitrite detection by a colorimetric assay with nitrite acted as the target analyte and TMB as the substrate. 74 In our case, the oxidase-like activity of g-CeO 2−x microspheres was evaluated as a new tool for the colorimetric detection of nitrite in aqueous media via a simpler protocol. For this purpose, the aqueous solutions prepared with different NaNO 2 concentrations in the range of 0.3−4.0 mM were interacted with TMB as the substrate using g-CeO 2−x microspheres as the nanozyme.…”

Nanozymes—Hitting the Biosensing “Target”

“…Many nanozymes are size-dependent since smaller nanozymes show a higher surface-to-volume ratio, which enhances the interactions with substrates because of the more active sites exposed [ 99 ]. But sometimes larger nanozymes may show higher activity, possibly because there are more metal ions [ 105 ], the presence of suitable valences [ 106 ], or the existence of redox reaction potential [ 107 ]. Excellent examples of these include two-dimensional (2D) nanomaterials, with the characteristic single-layer nanosheet structure that can include graphene, hexagonal boron nitride, transition metal dichalcogenides, graphitic carbon nitride, layered metal oxides, or layered double hydroxides.…”

Citric Acid-Functionalized Rhodium–Platinum Nanoparticles as Peroxidase Mimics for Determination of Cholesterol

“…Nanomaterial-based artificial enzymes, also known as nanozymes, are substitutes for natural enzymes because of their various advantages, including facile preparation, stability under ambient conditions, cost-effectiveness, and high catalytic activity. , Since the first nanozyme (Fe 3 O 4 NP) was identified as a peroxidase mimic, various nanomaterials such as carbon-based nanomaterials, noble metals, metal oxides, and their nanocomposites have been investigated as artificial enzyme mimics. − Of these nanomaterials, bimetallic nanoparticles are considered as attractive materials because the addition of a second metal induces variation in the particle shape, surface morphology, size, and chemical and physical properties. The combination of two different metallic elements in a single particle exhibits interesting properties, such as catalytic activity and chemical selectivity superior to those of individual constituent metals because of the synergistic or bifunctional effects. − Platinum (Pt)-based bimetallic nanoparticles are regarded as a remarkable catalyst because they exhibit excellent intrinsic enzyme-like activity with high sensitivity and stability. − As an additional component, rhodium (Rh) has been utilized as an excellent catalyst for hydrogenation reactions and oxidation reactions. , In addition, Rh-based nanomaterials exhibit intrinsic peroxidase-like activities. , Therefore, enhanced catalytic activity can be expected with the synergistic effects of Rh and Pt.…”