High-resolution colorimetric detection of lipase activity based on enzyme-controlled reshaping of gold nanorods

2019 ◽  
Vol 11 (17) ◽  
pp. 2286-2291 ◽  
Author(s):  
Hao Zhang ◽  
Shengnan Wu ◽  
Linghua Zhang ◽  
Ling Jiang ◽  
Fengwei Huo ◽  
...  
Keyword(s):  
High Resolution ◽  
Gold Nanorods ◽  
Lipase Activity ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Sensing Mechanism

The sensing mechanism of a high resolution colorimetric assay for the visual readout of lipase activity based on AuNR reshaping.

scholarly journals Pt Nanoparticles Anchored on NH2-MIL-101 with Efficient Peroxidase-Like Activity for Colorimetric Detection of Dopamine

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 140
Author(s):  
Jing Li ◽  
Keying Xu ◽  
Yang Chen ◽  
Jie Zhao ◽  
Peiyao Du ◽  
...  
Keyword(s):  
Active Sites ◽  
Clinical Medicine ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Pt Nanoparticles ◽  
Robust Detection ◽  
Color Changes ◽  
Relevant Role ◽  
Metal Organic ◽  
The Central Nervous System

Dopamine (DA) is an important catecholamine neurotransmitter that plays a highly relevant role in regulating the central nervous system, and abnormal DA content can cause many immune-related diseases. Hence, it is of significance to sensitively and specifically identify DA for clinical medicine. In this work, Pt/NH2-MIL-101 hybrid nanozymes with bimetallic catalytic centers were fabricated by forming coordinate bonds between Pt nanoparticles (Pt NPs) and –NH2 on metal–organic frameworks (MOF). The catalytic activity of Pt/NH2-MIL-101 was increased by 1.5 times via enlarging the exposure of more active sites and improving the activity of the active sites through the strategy of forming bimetallic catalytic centers. In the presence of DA, competing with 3, 3′, 5, 5′-tetramethylbenzidine (TMB) for the generated hydroxyl radicals (•OH), the blue oxidation state TMB (Ox-TMB) is reduced to colorless TMB, showing dramatic color changes. The Pt/NH2-MIL-101-based colorimetric assay enables the sensitive and robust detection of DA molecules with a detection limit of only 0.42 μM and has an observable potential in clinical applications.

scholarly journals Molecular Diagnostic of Ochratoxin A with Specific Aptamers in Corn and Groundnut via Fabrication of A Microfluidic Device

2021 ◽  
Author(s):  
Deepshikha Shahdeo ◽  
Azmat Ali Khan ◽  
Amer M Alanazi ◽  
Yun Suk Huh ◽  
Shruti Shukla ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Animal Health ◽  
Colorimetric Detection ◽  
Molecular Diagnostic ◽  
Detection Range ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
Analytical Device

Abstract Ochratoxin A (OTA) is one of the predominant mycotoxins that contaminate a wide range of food commodities. In the present study, a 36-mer aptamer was used as a molecular recognition element coupled with gold nanoparticles (AuNPs) for colorimetric detection of OTA in a microfluidic paper-based analytical device (µPADs). The µPADs consisted of three zones: control, detection, and sample, interconnected by channels. The biophysical characterizations of aptamer conjugated AuNPs were done by UV-vis spectroscopy (UV-vis), dynamic Light Scattering (DLS), and transmission electron microscopy (TEM). The developed colorimetric assay for OTA showed a limit of detection of 242, 545, and 95.69 ng/mL in water, corn, and groundnut, respectively. The HPLC detection method achieved acceptable coefficient in standard curves (r2 = 0.9995), better detection range, and recovery rates in spiked corn and groundnut samples as 43.61 ± 2.18% to 87.10 ± 1.82% and 42.01 ± 1.31% to 86.03 ± 2.64% after multiple sample extractions and cleanup steps. However, the developed µPADs analytical device had the potent ability to rapidly detect OTA without any extraction pre-requirement, derivatization, and cleanup steps, thus illustrating its feasibility in the animal health sector, agricultural, and food industries.

scholarly journals Enhancement of the Peroxidase-Like Activity of Iodine-Capped Gold Nanoparticles for the Colorimetric Detection of Biothiols

Biosensors ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 113 ◽  
Author(s):  
Chia-Chen Chang ◽  
Tsz-Lian Hsu ◽  
Chie-Pein Chen ◽  
Chen-Yu Chen
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Detection Limit ◽  
Enzymatic Activity ◽  
Catalytic Properties ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Synergetic Effect ◽  
Vis Spectroscopy ◽  
Wide Range

A colorimetric assay was developed for the detection of biothiols, based on the peroxidase-like activity of iodine-capped gold nanoparticles (AuNPs). These AuNPs show a synergetic effect in the form of peroxidase-mimicking activity at the interface of AuNPs, while free AuNPs and iodine alone have weak catalytic properties. Thus, iodine-capped AuNPs possess good intrinsic enzymatic activity and trigger the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB), leading to a change in color from colorless to yellow. When added to solution, biothiols, such as cysteine, strongly bind to the interface of AuNPs via gold-thiol bonds, inhibiting the catalytic activity of AuNPs, resulting in a decrease in oxidized TMB. Using this strategy, cysteine could be linearly determined, at a wide range of concentrations (0.5 to 20 μM), with a detection limit of 0.5 μM using UV-Vis spectroscopy. This method was applied for the detection of cysteine in diluted human urine.

Colorimetric detection of class A soybean saponins by coupling DNAzyme with the gap ligase chain reaction

2020 ◽  
Vol 12 (26) ◽  
pp. 3361-3367
Author(s):  
Wenshuai Li ◽  
Guorui Wu ◽  
Min Wang ◽  
Aiqin Yue ◽  
Weijun Du ◽  
...  
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Chain Reaction ◽  
Ligase Chain Reaction ◽  
Naked Eye ◽  
Class A

We propose a colorimetric assay based on the coupling of gap ligase chain reaction (Gap-LCR) with DNAzyme to detect the target GmSg-1 genes of class A soybean saponins with the naked eye, without the involvement of expensive instruments.

scholarly journals Colorimetric Detection of Sulfide Anions via Redox-Modulated Surface Chemistry and Morphology of Au-Hg Nanorods

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaotian Zhu ◽  
Chang Liu ◽  
Jie Liu
Keyword(s):  
Surface Chemistry ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Localized Surface Plasmon ◽  
Wavelength Shift ◽  
Colorimetric Sensing ◽  
Leather Industry ◽  
Colorimetric Response ◽  
Sensitivity And Selectivity

A new colorimetric assay for the detection of sulfide anions with high sensitivity and selectivity is reported, utilizing Au-Hg alloy nanorods (Au-HgNRs) as probe. Au-HgNRs were prepared by modifying gold nanorods (AuNRs) with reducing agent and mercury ions. In an aqueous solution with sulfide anions, the formation of mercuric sulfide due to redox reaction between the amalgams and sulfide anions greatly changed the surface chemistry and morphology of the Au-HgNRs, leading to a red shift of the localized surface plasmon resonance (LSPR) absorption peak, accompanied by a change in colorimetric response. A good linear relationship was obtained between the LSPR peak wavelength shift and concentration of sulfide anion in the range of 1 × 10−5−1 × 10−4 mol/L. The selectivity of this method has been investigated by other anions. The colorimetric sensing system successfully detected sulfide in wastewater from leather industry.

High-Resolution Colorimetric Assay for Rapid Visual Readout of Phosphatase Activity Based on Gold/Silver Core/Shell Nanorod

2014 ◽  
Vol 6 (20) ◽  
pp. 18243-18250 ◽  
Author(s):  
Zhuangqiang Gao ◽  
Kaichao Deng ◽  
Xu-Dong Wang ◽  
Manuel Miró ◽  
Dianping Tang
Keyword(s):  
High Resolution ◽  
Phosphatase Activity ◽  
Colorimetric Assay ◽  
Core Shell ◽  
Gold Silver ◽  
Silver Core

scholarly journals Phytosynthesis of Palladium Nanoclusters: An Efficient Nanozyme for Ultrasensitive and Selective Detection of Reactive Oxygen Species

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3349
Author(s):  
Ravi Mani Tripathi ◽  
Sang J. Chung
Keyword(s):  
Reactive Oxygen Species ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Reactive Oxygen ◽  
Cost Effective ◽  
Oxygen Species ◽  
Distribution Profile ◽  
Fenton’S Reaction ◽  
Peroxidase Mimetic ◽  
H2o2 Detection

Hydrogen peroxide is a low-reactivity reactive oxygen species (ROS); however, it can easily penetrate cell membranes and produce highly reactive hydroxyl radical species through Fenton’s reaction. Its presence in abnormal amounts can lead to serious diseases in humans. Although the development of a simple, ultrasensitive, and selective method for H2O2 detection is crucial, this remains a strategic challenge. The peroxidase mimetic activity of palladium nanoclusters (PdNCs) has not previously been evaluated. In this study, we developed an ultrasensitive and selective colorimetric detection method for H2O2 using PdNCs. An unprecedented eco-friendly, cost-effective, and facile biological method was developed for the synthesis of PdNCs. This is the first report of the biosynthesis of PdNCs. The synthesized nanoclusters had a significantly narrow size distribution profile and high stability. The nanoclusters were demonstrated to possess a peroxidase mimetic activity that could oxidize peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB). Various interfering substances in serum (100 μM phenylalanine, cysteine, tryptophan, arginine, glucose, urea, Na+, Fe2+, PO43−, Mn+2, Ca2+, Mg2+, Zn2+, NH4+, and K+) were included to evaluate the selectivity of the assay, and oxidation of TMB occurred only in the presence of H2O2. Therefore, PdNCs show an efficient nanozyme for the peroxidase mimetic activity. The assay produced a sufficient signal at the ultralow concentration of 0.0625 µM H2O2. This colorimetric assay provides a real-time, rapid, and easy-to-use platform for the detection of H2O2 for clinical purposes.

MOF-derived porous ZnO-Co3O4 nanocages as peroxidase mimics for colorimetric detection of copper(ii) ions in serum

The Analyst ◽  
2021 ◽  
Author(s):  
Jie Lv ◽  
Cong Zhang ◽  
Shuangling Wang ◽  
Meng Li ◽  
Wei Guo
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Copper Ion ◽  
Ion Detection ◽  
Peroxidase Mimics

A novel colorimetric assay was developed for copper ion detection based on peroxidase-like activity of MOF-derived porous ZnO-Co3O4 nanocages.

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