Sensitive Colorimetric Detection Of Glucose Research Articles

Norepinephrine-induced AuPd aerogels with peroxidase- and glucose oxidase-like activity for colorimetric determination of glucose.

A simple and efficient method was used to synthesize norepinephrine-induced AuPd aerogels (AuPd-NE) with dual enzyme properties, i.e.glucose oxidase-like property, and peroxidase-like property. Thus, AuPd-NE aerogels can be considered as a tandem nanozyme with tandem enzyme-like activity. In the presence of AuPd-NE aerogels, glucose can be decomposed into gluconic acid and H2O2. Then, H2O2 will continue to decompose into ·OH and H2O. The generated ·OH will oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue products of ox-TMB. Accordingly, an enzyme-free method based on AuPd-NE aerogels was proposed for sensitive colorimetric detection of glucose. The linear range of the developed method was 30 to 250μM, and the limit of detection was 10μM. The method presents reliable applicability for blood glucose detection in human serum samples. This study will deepen the understanding of tandem nanozymes and then rationally design tandem nanozymes for many fascinating biomedical applications. A simple, sensitive and reliable one-pot enzyme-free colourimetric assay for glucose was developed.

An interrelated CataFlower enzyme system for sensitively monitoring sweat glucose

An accurate measurement of sweat glucose is a promising alternative to invasive finger prick blood test, and may provide effective self-monitoring of blood glucose with good patient compliance. Herein, an interrelated catalytic enzyme system has been developed, termed as CataFlower, which is composed of nanoflower MoS2 (peroxidase) decorated with GOx (glucose oxidase) and MnO2 (oxygen generator), and exhibits synergistic oxidative capability for sensitively monitoring sweat glucose. CataFlower can not only generate oxygen in situ to maximize GOx activity, but promote peroxidase-triggered H2O2 oxidation of methylene blue, resulting in sensitive colorimetric detection of glucose. We identify that CataFlower can precisely detect glucose with a detection limit of 10 μM, allowing for measuring glucose levels in different biological samples, such as blood and urine. Particularly, CataFlower is capable of monitoring dynamic changes in sweat glucose with high sensitivity and accuracy during exercise. Therefore, CataFlower provides a stepping stone to eliminate invasive blood tests, significantly improving the diagnosis and management of diabetes mellitus.

Green synthesis of Au@WSe2 hybrid nanostructures with the enhanced peroxidase-like activity for sensitive colorimetric detection of glucose

Green synthesis of Au@WSe2 hybrid nanostructures with the enhanced peroxidase-like activity for sensitive colorimetric detection of glucose

Green synthesis of platinum nanoclusters using lentinan for sensitively colorimetric detection of glucose

The sensitive colorimetric detection of glucose using nanomaterials has been attracting considerable attention. To improve the detection sensitivity, highly stable lentinan stabilized platinum nanoclusters (Pt-LNT NCs) were prepared, in which lentinan was employed as a mild reductant and stabilizer. The size of platinum nanoclusters (Pt NCs) was only 1.20 ± 0.29 nm. Pt-LNT NCs catalyzed the oxidation of substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) to produce a blue oxidation product with absorption peak at 652 nm, indicating their peroxidase-like properties. Their enzymatic kinetics followed typical Michaelis-Menten theory. In addition, fluorescence experiments confirmed their ability to efficiently catalyze the decomposition of H2O2 to generate •OH, which resulted in the peroxidase-like mechanism of Pt-LNT NCs. Moreover, a colorimetric method for highly selective and sensitive detection of glucose was established by using Pt-LNT NCs and glucose oxidase. The linear range of glucose detection was 5–1000 μM and the detection limit was 1.79 μM. Finally, this method was further used for detection of glucose in human serum and human urine. The established colorimetric method may promote the development of biological detection and environmental chemistry in the future.

Highly sensitive colorimetric detection of glucose through glucose oxidase and Cu2+-catalyzed 3,3',5,5'-tetramethylbenzidine oxidation.

We develop a glucose oxidase (GOx)-mediated strategy for detecting glucose based on oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB), which is generated from Cu2+-catalyzed 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 reaction, as colorimetric readout. The sensing system involves two processes: generation of H2O2 from GOx-catalyzed oxidation of glucose, and H2O2-induced the oxidization of TMB via the catalysis of Cu2+. The H2O2 formed by GOx-catalyzed oxidation of glucose oxidizes colorless TMB to blue oxTMB, thus enhancing the absorbance intensity at 670 nm. Therefore, we draw a conclusion that the enhancement in colorimetric signal relies directly on H2O2 concentration, which, in turn, depends on glucose concentration. This color change can be used not only for visual detection of glucose by naked eyes but for reliable glucose quantification in the range from 1 to 100 nM with a detection limit of 0.21 nM. The method possesses the following advantages: simple design, low experimental cost, and no any additional experimental equipment for heating, illuminating, or bubbling.

Biocompatible bimetallic Au-Ni doped graphitic carbon nitride sheets: A novel peroxidase-mimicking artificial enzyme for rapid and highly sensitive colorimetric detection of glucose

We report herein, a novel two dimensional (2D) nanocomposite sensor towards detection of glucose via a simple colorimetric detection technique. The graphitic carbon nitride (g-C3N4) sheets are decorated with Au-Ni bimetallic nanoparticles with size ˜11 nm by a simple chemical reduction technique. The Au-Ni/g-C3N4 nanocomposites is found to possess intrinsic peroxidase like activity capable of catalysing the oxidation of 3,3ʹ,5,5ʹ-tetramethylbenzidine (TMB) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) in presence of H2O2 and exhibits substrate affinity much higher than biological horseradish peroxidase as well as other reported nanozymes. Also, there is a scanty of literature reports on bimetallic g-C3N4 based nanozymes towards detection of any biomolecules related to human life. The peroxidase like activity combined with glucose oxidase (GOx) helped in developing a simple, sensitive and a specific colorimetric method for glucose detection with a detection limit of 1.7 μM and a linear detection range between 0.5‒30 μM. The colorimetric method for detection of glucose was further successfully extended towards detection of glucose in real serum samples with comparable results to standard hospital method. Additionally, the nanocomposites are non-cytotoxic towards human umbilical vein endothelial cell line (HUVEC) which demonstrates its high biocompatibility and suitability for biosensor applications. Our results thus demonstrate that our method based on Au-Ni/g-C3N4 is reliable, economical, feasible and highly efficient.

Enhanced peroxidase-like activity of Mo-doped ceria nanoparticles for sensitive colorimetric detection of glucose

Ultra-small nanoparticles of Mo-doped ceria (Mo/CeO2 NPs) possess enhanced peroxidase-like catalytic activity and these enzyme mimics are used here for the successful quantitative determination of blood glucose via a colorimetric method.

Sensitive colorimetric detection of glucose and cholesterol by using Au@Ag core–shell nanoparticles

Sensitive colorimetric detection of glucose and cholesterol by using Au@Ag core–shell nanoparticles.

Highly sensitive colorimetric detection of glucose and uric acid in biological fluids using chitosan-modified paper microfluidic devices

This paper describes the modification of microfluidic paper-based analytical devices (μPADs) with chitosan to improve the analytical performance of colorimetric measurements associated with enzymatic bioassays. Chitosan is a natural biopolymer extensively used to modify biosensing surfaces due to its capability of providing a suitable microenvironment for the direct electron transfer between an enzyme and a reactive surface. This hypothesis was investigated using glucose and uric acid (UA) colorimetric assays as model systems. The best colorimetric sensitivity for glucose and UA was achieved using a chromogenic solution composed of 4-aminoantipyrine and sodium 3,5-dichloro-2-hydroxy-benzenesulfonate (4-AAP/DHBS), which provided a linear response for a concentration range between 0.1 and 1.0 mM. Glucose and UA were successfully determined in artificial serum samples with accuracies between 87 and 114%. The limits of detection (LODs) found for glucose and UA assays were 23 and 37 μM, respectively. The enhanced analytical performance of chitosan-modified μPADs allowed the colorimetric detection of glucose in tear samples from four nondiabetic patients. The achieved concentration levels ranged from 130 to 380 μM. The modified μPADs offered analytical reliability and accuracy as well as no statistical difference from the values achieved through a reference method. Based on the presented results, the proposed μPAD can be a powerful alternative tool for non-invasive glucose analysis.

Highly sensitive colorimetric detection of glucose in a serum based on DNA-embeded Au@Ag core–shell nanoparticles

Glucose is a key energy substance in diverse biology and closely related to the life activities of the organism. To develop a simple and sensitive method for glucose detection is extremely urgent but still remains a key challenge. Herein, we report a colorimetric glucose sensor in a homogeneous system based on DNA-embedded core–shell Au@Ag nanoparticles. In this assay, a glucose substrate was first catalytically oxidized by glucose oxidase to produce H2O2 which would further oxidize and gradually etch the outer silver shell of Au@Ag nanoparticles. Afterwards, the solution color changed from yellow to red and the surface plasmon resonance (SPR) band of Au@Ag nanoparticles declined and red-shifted from 430 to 516 nm. Compared with previous silver-based glucose colorimetric detection strategies, the distinctive SPR band change is superior to the color variation, which is critical to the high sensitivity of this assay. Benefiting from the outstanding optical property, robust stability and well-dispersion of the core–shell Au@AgNPs hybrid, this colorimetric assay obtained a detection limit of glucose as low as 10 nM, which is at least a 10-fold improvement over other AgNPs-based procedures. Moreover, this optical biosensor was successfully employed to the determination of glucose in fetal bovine serum.

Anisotropic gold nanoparticles for the highly sensitive colorimetric detection of glucose in human urine

PEDOT:PSS modified anisotropic gold nanoparticles (GNP) for the colorimetric detection of glucose in urine.