An ultra-sensitive colorimetric assay for reliable visual detection of telomerase activity

The Analyst ◽  
2017 ◽  
Vol 142 (17) ◽  
pp. 3235-3240 ◽  
Author(s):  
Yaocai Wang ◽  
Luzhu Yang ◽  
Yanjun Wang ◽  
Wei Liu ◽  
Baoxin Li ◽  
...  
Keyword(s):  
Hela Cell ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Telomerase Activity ◽  
Cell Lysates ◽  
Naked Eye ◽  
Vis Spectroscopy

We proposed a sensitive colorimetric assay for detecting telomerase activity. The telomerase activity of 5 and 20 HeLa cell lysates can be detected via UV-vis spectroscopy and the naked eye, respectively.

scholarly journals A simple, fast, and sensitive colorimetric assay for visual detection of berberine in human plasma by NaHSO4-optimized gold nanoparticles

RSC Advances ◽  
2017 ◽  
Vol 7 (55) ◽  
pp. 34746-34754 ◽  
Author(s):  
Ziwei Hu ◽  
Mingshan Xie ◽  
Danting Yang ◽  
Dong Chen ◽  
Jingyi Jian ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Human Plasma ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Naked Eye ◽  
Vis Spectroscopy ◽  
Colorimetric Visualization

Herein, we report a simple, fast and sensitive colorimetric visualization of berberine in human plasma using NaHSO4-optimized gold nanoparticles. The LOD in human plasma is 0.24 μg mL−1by the naked eye and 0.06 μg mL−1by UV-vis spectroscopy.

Visual detection of cancer cells by using in situ grown functional Cu2−xSe/reduced graphene oxide hybrids acting as an efficient nanozyme

The Analyst ◽  
2019 ◽  
Vol 144 (2) ◽  
pp. 716-721 ◽  
Author(s):  
Qing Juan Guo ◽  
Zi Yu Pan ◽  
Chen Men ◽  
Wen Yi Lv ◽  
Hong Yan Zou ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Cancer Cells ◽  
Reduced Graphene Oxide ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Signal Transducer ◽  
Naked Eye ◽  
Reduced Graphene ◽  
Se Nanoparticles

Cu2−xSe nanoparticles grown in situ on reduced graphene oxide (Cu2−xSe/rGO) acted as an efficient nanozyme. Using the Cu2−xSe/rGO as a signal transducer, a colorimetric assay for cancer cells with the naked eye has been developed.

An Effort to Making a Colorimitric Nano-Biosensor for Vibrio cholera Detection

2020 ◽  
Vol 16 (5) ◽  
pp. 793-804
Author(s):  
Naimeh Mahheidari ◽  
Jamal Rashidiani ◽  
Hamid Kooshki ◽  
Khadijeh Eskandari
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Assay ◽  
Au Nanoparticle ◽  
Bacteria Detection ◽  
Great Promise ◽  
Bacterial Cells ◽  
Vibrio Cholera ◽  
Minimum Concentration ◽  
Vis Spectroscopy ◽  
Fast Procedure

Background: Today, nanoparticles hold great promise in biomedical researches and applications including bacteria detection. The rapid and sensitive outcomes of bacteria detection strategies using nanoparticle conjugates become determinative, especially in bacterial outbreaks. In the current research, we focused on detecting V. cholera bacteria and its toxin using a thiocyanate/Au nanoparticle. Thiocyanate adsorbed strongly on the surface of gold nanoparticles and changed the surface by enhancing surface plasmon resonance of gold nanoparticles. Objective: This method is tried to introduce a simple and fast procedure to assay vibrio cholera. So, it is observed by the naked eyes as well. Methods: We used two antibodies (Ab) for V. cholera detection: a) a primary antibody conjugated to magnetic nanoparticles (MNPs) for trapping V. cholera bacterial cells, and b) a secondary Abconjugated thiocyanate-GNPs as a colorimetric detector. Then, an immuno-magnetic separation system connected to a colorimetric assay was designed based on the GNPs. The results were measured by ultraviolet-visible (UV-Vis) spectroscopy. Results: The results showed that gold nanoparticles are an appropriate optical assay for detecting biological samples in a minimum concentration and also it can be easily seen by the naked eyes. The linear range of this biosensor is 3.2×104 to 28×104 cells per ml. Conclusion: In this research, a colorimetric immune assay based on gold nanoparticles was designed to improve the sensitivity of V. cholera detection. Also, this method can be used for the detection of other biological agents.

scholarly journals End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

2014 ◽  
Vol 10 ◽  
pp. 2263-2269 ◽  
Author(s):  
Carolin Fleischmann ◽  
Hendrik Wöhlk ◽  
Helmut Ritter
Keyword(s):  
Ethylene Glycol ◽  
Cycloaddition Reaction ◽  
Supramolecular Interactions ◽  
Poly Ethylene Glycol ◽  
Naked Eye ◽  
Vis Spectroscopy ◽  
End Group Functionalization ◽  
Interesting Approach ◽  
Poly Ethylene ◽  
End Group

The synthesis of a new phenolphthalein azide derivative, which can be easily utilized in polymer analogous reactions, is presented. The subsequent cycloaddition reaction with propargyl-functionalized methoxypoly(ethylene glycol) yielded polymers bearing phenolphthalein as the covalently attached end group. In presence of per-β-cyclodextrin-dipentaerythritol, the formation of stable inclusion complexes was observed, representing an interesting approach towards the formation of star shaped polymers. The decolorization of a basic polymer solution caused by the complexation was of great advantage since this behavior enabled following the complex formation by UV–vis spectroscopy and even the naked eye.

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.

Visualizing telomerase activity for tumour identification by hybridization-triggered ratiometric fluorescence

2019 ◽  
Vol 55 (14) ◽  
pp. 2035-2038 ◽  
Author(s):  
Manli Zheng ◽  
Ruilong Zhang ◽  
Xiaohe Tian ◽  
Zhengjie Liu ◽  
Zhongping Zhang
Keyword(s):  
Telomerase Activity ◽  
Ratiometric Fluorescence ◽  
Naked Eye

We developed a ratiometric fluorescence strategy for visualising telomerase activity to aid tumour identification by the naked eye.

Visual detection of 8-OHdG based on the aggregation of gold nanoparticles capped with the anti-8-OHdG antibody

2015 ◽  
Vol 7 (19) ◽  
pp. 8360-8365 ◽  
Author(s):  
Liping Wu ◽  
Wendan Pu ◽  
Yue Liu ◽  
Huawen Zhao ◽  
Weiqun Shu
Keyword(s):  
Gold Nanoparticles ◽  
Quantitative Determination ◽  
Rapid Method ◽  
Visual Detection ◽  
Color Change ◽  
Naked Eye ◽  
Absorption Wavelength

AuNPs, capped with anti-8-OHdG antibody, aggregate when 8-OHdG was added, resulting in color change and redshift of absorption wavelength. So a simple and rapid method to selectively determine 8-OHdG was developed and semi-quantitative determination could be achieved by the naked eye.

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