Oxidase-like Nanozyme Activity of Manganese Metal–Organic Framework Nanosheets for Colorimetric and Fluorescence Sensing of l-Cysteine

Abstract

The utilization of ultrathin Mn-metal−organic framework (Mn-UMOF) nanosheets for oxidase-like nanozyme activity has been demonstrated. The Mn-UMOF exhibited superior nanozyme activity to oxidize chromogenic TMB and ABTS than the bulk Mn-BMOF. Based on this fact, a platform for the colorimetric sensing of L-cysteine (L-cys) has been established over the detection of other amino acids and natural compounds such as urea and glucose. In addition, the Mn-UMOF has the capability of catalyzing the oxidation of amplex red to the fluorescent first oxidized product, which has been used to develop a fluorescence turn-off sensor for the selective sensing of L-cys.

Nanozyme Rich in Oxygen Vacancies Derived from Mn-Based Metal–Organic Gel for the Determination of Alkaline Phosphatase

“…In previous study, the oxidase-like activity had a close connection with the generation of free radicals, including hydroxyl radicals (•OH), singlet oxygen ( 1 O 2 ), and superoxide anions (O 2 •– ). − Besides, •OH, 1 O 2 , and O 2 •– could be captured by IPA, TRY, and PBQ respectively. , As depicted in Figure A, the relative catalytic activity of IPA and TRY group did not show apparent difference with the increase in concentrations of scavengers compared with the group without scavenger. While in the PBQ group, the relative catalytic activity decreased dramatically as the concentrations of PBQ increased, which indicated the vital role of O 2 •– in the TMB oxidation process.…”

A novel Salen-based dual channel sensor for easy and selective nanomolar detection of l-cysteine

“…In ref. 62, the authors detected the presence of l -cyst using Mn-metal–organic framework (Mn-UMOF) nanosheets as sensors. Even though this sensor offers a dual channel sensing, the synthesis of the sensor itself is cumbersome which may limit its widespread utilisation.…”

Tailoring the Enzyme-Mimetic Activity and Surface Nanostructure of Metal-Phenolic Platform for Colorimetric Detection of l-Cysteine

“…The activity of nanomaterials can be tuned by their shapes, surface chemical structures, pore sizes, and valences of metal ions. Thus, the rational design and precise construction of the morphology and valences provide the huge potential for customizing the enzyme-like activities of nanomaterials. − Unsatisfactorily, these enzyme-like nanomaterials such as noble metals, metal oxides, and carbon nanostructures require additional amount of energy consumption to meet synthesis conditions (high temperature, high pressure, strong oxidizing environment, electric energy, ultrasonic, and so on), which also make the synthesis process harmful to the environment. ,− For example, MnCo 2 O 4 , FeP@C, and ov-Mn 3 O 4 , are synthesized up to 800 °C; V 2 O 5 and Mn-UMOF require the additional energy supply, such as ultrasonic; LaMnO 3+δ , Mo 6+ -Doped Co 3 O 4 , and NiO need organic solvents. Meanwhile, considering the intersection of catalytic chemistry and biosensing, the biosecurity and potential toxicity of the platforms remain challenging and worrisome, which significantly limit further clinical application.…”

“…11−13 Unsatisfactorily, these enzyme-like nanomaterials such as noble metals, metal oxides, and carbon nanostructures require additional amount of energy consumption to meet synthesis conditions (high temperature, high pressure, strong oxidizing environment, electric energy, ultrasonic, and so on), which also make the synthesis process harmful to the environment. 3,14−26 For example, MnCo 2 O 4 , 27 FeP@C, 28 and ov-Mn 3 O 4 , 16 are synthesized up to 800 °C; V 2 O 5 29 and Mn-UMOF 22 require the additional energy supply, such as ultrasonic; LaMnO 3+δ , 19 Mo 6+ -Doped Co 3 O 4 , 20 of catalytic chemistry and biosensing, the biosecurity and potential toxicity of the platforms remain challenging and worrisome, which significantly limit further clinical application. Thus, exploring innovative and green strategies is of great significance for developing cost-efficient and high-performance multienzyme-like platforms.…”