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.

scholarly journals High-performance Saccharomyces cerevisiae-based biosensor for heavy metal detection

2021 ◽  
Author(s):  
Jifeng Yuan ◽  
Cong Fan ◽  
Danli Zhang ◽  
Qiwen Mo
Keyword(s):  
Heavy Metals ◽  
Saccharomyces Cerevisiae ◽  
High Performance ◽  
Colorimetric Assay ◽  
Copper Ion ◽  
Low Noise ◽  
Detection Methods ◽  
Ion Detection ◽  
Engineered Yeast ◽  
Increasing Demand

Heavy metals, i.e., Cu(II), are harmful to the environment. There is an increasing demand to develop inexpensive detection methods for heavy metals. Here, we developed a yeast biosensor with reduced-noise and improved signal output for potential on-site copper ion detection. The copper-sensing circuit was achieved by employing a secondary genetic layer to control the galactose-inducible (GAL) system in Saccharomyces cerevisiae. The reciprocal control of the Gal4 activator and Gal80 repressor under copper-responsive promoters resulted in a low-noise and ultrasensitive yeast biosensor for the copper ion detection. Furthermore, we developed a betaxanthin-based colorimetric assay, as well as 2-phenylethanol and styrene-based olfactory outputs for the copper ion detection. Notably, our engineered yeast sensor confers a narrow range switch-like behavior, which can give a “yes/no” response when coupled with betaxanthin-based visual phenotype. Taken together, we envision that the design principle established here might be applicable for developing other sensing systems for various chemical detections.

Multi-stimuli responsive fluorescence of amphiphilic AIEgen copolymers for ultrafast, highly sensitive and selective copper ion detection in water

2021 ◽  
pp. 130241
Author(s):  
Pham Quoc Nhien ◽  
Po-Hsun Wu ◽  
Chia-Hua Wu ◽  
Judy I. Wu ◽  
Bui Thi Buu Hue ◽  
...  
Keyword(s):  
Copper Ion ◽  
Stimuli Responsive ◽  
Ion Detection ◽  
Highly Sensitive

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.

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