Syringe filter-based DNA aptamer-enzyme-linked colorimetric assay of Salmonella on lettuce

2022 ◽  
pp. 106406
Author(s):  
John G. Bruno
Keyword(s):  
Colorimetric Assay ◽  
Dna Aptamer ◽  
Syringe Filter

Highly sensitive and universal detection strategy based on a colorimetric assay using target-specific heterogeneous sandwich DNA aptamer

2020 ◽  
Vol 1123 ◽  
pp. 73-80 ◽  
Author(s):  
Juyoung Kang ◽  
Gyuho Yeom ◽  
Hyungjun Jang ◽  
Chin-Ju Park ◽  
Min-Gon Kim
Keyword(s):  
Colorimetric Assay ◽  
Dna Aptamer ◽  
Detection Strategy ◽  
Highly Sensitive ◽  
Universal Detection

Development of a DNA aptamer selection method based on the heterogeneous sandwich form and its application in a colorimetric assay for influenza A virus detection

2019 ◽  
Vol 43 (18) ◽  
pp. 6883-6889 ◽  
Author(s):  
Juyoung Kang ◽  
Gyuho Yeom ◽  
Su-Ji Ha ◽  
Min-Gon Kim
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Colorimetric Assay ◽  
Signal To Noise Ratio ◽  
Virus Detection ◽  
Selection Method ◽  
Dna Aptamer ◽  
Signal To Noise ◽  
Aptamer Selection ◽  
Sandwich Type

In this paper, we introduce an effective method for selecting aptamer that increases the signal-to-noise ratio in a heterogenous sandwich-type immunosensor and confirm the efficiency of selected aptamer candidates in the colorimetric assay. Using the proposed method, four aptamer candidates withKdvalues ranging from 77.6 nM to 125.7 nM were obtained.

Rapid Quantification of Prion Proteins

2019 ◽  
Author(s):  
Matthew Healey ◽  
Muttuswamy Sivakumaran ◽  
Mark Platt
Keyword(s):  
Prion Proteins ◽  
Prion Diseases ◽  
Sample Volume ◽  
Cellular Prion Protein ◽  
Dna Aptamer ◽  
Superparamagnetic Beads ◽  
Resistive Pulse ◽  
Large Sample Volume ◽  
Complex Sample ◽  
Neurological Conditions

<p>Prion diseases are a group of fatal transmissible neurological conditions caused by the change in conformation of the normal intrinsic cellular prion protein (PrP<sup>C</sup>) in to the highly ordered insoluble amyloid state conformer (PrP<sup>SC</sup>). We present a rapid assay using Aptamers and Resistive Pulse Sensing, RPS, to extract and quantify proteins from complex sample matrices, demonstrate with the quantification of PrP<sup>c</sup>. We functionalise the surface of superparamagnetic beads, SPBs, with a DNA aptamer. First SPB’s termed P-Beads, are used to pre-concentrate the analyte from a large sample volume. The PrP<sup>c</sup> protein is then eluted from the P-Beads before aptamer modified sensing beads, S-Beads, are added. The velocity of the S-Beads through the nanopore reveals the concentration of the PrP<sup>c</sup> protein. The process is done in under an hour and allows the detection of picomol’s of protein. The technique could be easily adopted to the mutated version of the protein and integrated into clinical workflows for the screening of blood donations and transfusions. </p>

Development of a colorimetric protein phosphorylation assay for detecting cyanobacterial toxins

1995 ◽  
Vol 31 (5-6) ◽  
pp. 47-49 ◽  
Author(s):  
C. Ash ◽  
C. MacKintosh ◽  
R. MacKintosh ◽  
C. R. Fricker
Keyword(s):  
Protein Phosphorylation ◽  
Colorimetric Assay ◽  
Cyanobacterial Toxins ◽  
Sensitive Determination

A new colorimetric assay is described, based on inhibition of protein phosphotases, that enables the rapid, simple and sensitive determination of the concentration of toxins from cyanobacteria.

Design, Synthesis, In vitro and In silico Evaluation of New Hydrazonebased Antitumor Agents as Potent Akt Inhibitors

2020 ◽  
Vol 17 (11) ◽  
pp. 1380-1392
Author(s):  
Emine Merve Güngör ◽  
Mehlika Dilek Altıntop ◽  
Belgin Sever ◽  
Gülşen Akalın Çiftçi
Keyword(s):  
Cell Line ◽  
Anticancer Agents ◽  
In Silico ◽  
Antitumor Agents ◽  
Colorimetric Assay ◽  
Fibroblast Cell ◽  
Lipinski’S Rule ◽  
In Silico Docking ◽  
Embryonic Fibroblast

Background: Akt is overexpressed or activated in a variety of human cancers, including gliomas, lung, breast, ovarian, gastric and pancreatic carcinomas. Akt inhibition leads to the induction of apoptosis and inhibition of tumor growth and therefore extensive efforts have been devoted to the discovery of potent antitumor drugs targeting Akt. Objectives: The objective of this work was to identify potent anticancer agents targeting Akt. Methods: New hydrazone derivatives were synthesized and investigated for their cytotoxic effects on 5RP7 H-ras oncogene transformed rat embryonic fibroblast and L929 mouse embryonic fibroblast cell lines. Besides, the apoptotic effects of the most active compounds on 5RP7 cell line were evaluated using flow cytometry. Their Akt inhibitory effects were also investigated using a colorimetric assay. In silico docking and Absorption, Distribution, Metabolism and Excretion (ADME) studies were also performed using Schrödinger’s Maestro molecular modeling package. Results and Discussion: Compounds 3a, 3d, 3g and 3j were found to be effective on 5RP7 cells (with IC50 values of <0.97, <0.97, 1.13±0.06 and <0.97 μg/mL, respectively) when compared with cisplatin (IC50= 1.87±0.15 μg/mL). It was determined that these four compounds significantly induced apoptosis in 5RP7 cell line. Among them, N'-benzylidene-2-[(4-(4-methoxyphenyl)pyrimidin- 2-yl)thio]acetohydrazide (3g) significantly inhibited Akt (IC50= 0.5±0.08 μg/mL) when compared with GSK690693 (IC50= 0.6±0.05 μg/mL). Docking studies suggested that compound 3g showed good affinity to the active site of Akt (PDB code: 2JDO). According to in silico ADME studies, the compound also complies with Lipinski's rule of five and Jorgensen's rule of three. Conclusion: Compound 3g stands out as a potential orally bioavailable cytotoxic agent and apoptosis inducer targeting Akt.

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 Suitability of the Cyclic Voltammetry Measurements and DPPH• Spectrophotometric Assay to Determine the Antioxidant Capacity of Food-Grade Oenological Tannins

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2925 ◽  
Author(s):  
Arianna Ricci ◽  
Giuseppina Paola Parpinello ◽  
Nemanja Teslić ◽  
Paul Andrew Kilmartin ◽  
Andrea Versari
Keyword(s):  
Cyclic Voltammetry ◽  
Colorimetric Assay ◽  
Radical Scavenging ◽  
Calibration Graph ◽  
Spectrophotometric Assay ◽  
Experimental Conditions ◽  
Fast Analysis ◽  
Cv Measurements ◽  
And Control ◽  
Analytical Approaches

Twenty commercially available oenological tannins (including hydrolysable and condensed) were assessed for their antiradical/reducing activity, comparing two analytical approaches: The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging spectrophotometric assay and the cyclic voltammetry (CV) electrochemical method. Electrochemical measurements were performed over a −200 mV–500 mV scan range, and integrated anodic currents to 500 mV were used to build a calibration graph with (+)-catechin as a reference standard (linear range: From 0.0078 to 1 mM, R2 = 0.9887). The CV results were compared with the DPPH• assay (expressed as % of radical scavenged in time), showing high correlation due to the similarity of the chemical mechanisms underlying both methods involving polyphenolic compounds as reductants. Improved correlation was observed by increasing the incubation time with DPPH• to 24 h (R2 = 0.925), demonstrating that the spectrophotometric method requires a long-term incubation to complete the scavenging reaction when high-molecular weight tannins are involved; this constraint has been overcome by using instant CV measurements. We concluded that the CV represents a valid alternative to the DPPH• colorimetric assay, taking advantage of fast analysis and control on the experimental conditions and, because of these properties, it can assist the quality control along the supply chain.

Multiplexed Optical Detection of Plasma Porphyrins Using DNA Aptamer-Functionalized Carbon Nanotubes

2013 ◽  
Vol 85 (17) ◽  
pp. 8391-8396 ◽  
Author(s):  
Jing Pan ◽  
Hanyu Zhang ◽  
Tae-Gon Cha ◽  
Haorong Chen ◽  
Jong Hyun Choi
Keyword(s):  
Carbon Nanotubes ◽  
Optical Detection ◽  
Dna Aptamer ◽  
Functionalized Carbon Nanotubes
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