scholarly journals Reverse-Bumpy-Ball-Type-Nanoreactor-Loaded Nylon Membranes as Peroxidase-Mimic Membrane Reactors for a Colorimetric Assay for H2O2

Sensors ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 465 ◽  
Author(s):  
Ying Tong ◽  
Xiangyu Jiao ◽  
Hankun Yang ◽  
Yongqiang Wen ◽  
Lei Su ◽  
...  
2018 ◽  
Vol 1 (2) ◽  
pp. 382-388 ◽  
Author(s):  
Junning Wang ◽  
Xue Yang ◽  
Tianxiang Wei ◽  
Jianchun Bao ◽  
Qinshu Zhu ◽  
...  

2021 ◽  
Author(s):  
Chen Hou ◽  
Linhui Fu ◽  
Yang Wang ◽  
Wenqiang Chen ◽  
Fang Chen ◽  
...  

Abstract Rapid and accurate detection of phenolic wastewater from industries has created global concern. Herein, core-shell magnetic cellulose nanocrystals supported MOF (Fe3O4/CNC@ZIF-8) with robust peroxidase-like activity was synthesized with tannic acid as modifier and bridge. The peroxidase-mimic catalytic activity of as-prepared Fe3O4/CNC@ZIF-8 was further investigated using o-phenylenediamine (OPD) as peroxidase substrates in the presence of H2O2. Moreover, the experimental conditions were optimized and the kinetic analysis results showed that Fe3O4/CNC@ZIF-8 had higher affinity towards both the substrate OPD and H2O2 than horseradish peroxidase (HRP). Finally, a phenol colorimetric assay with a linear range of 2-200 µM and a detection limit of 0.316 µM was constructed. The catalytic mechanism of Fe3O4/CNC@ZIF-8 with phenol was further investigated by fluorescence test and the generated •OH was proved to act a crucial role to produce quinoid radicals. Additionally, the synthesized magnetic material had excellent stability and recyclability and ease to separation. These results suggest that the Fe3O4/CNC@ZIF-8 may be one of the promising candidates as peroxidase mimic for colorimetric detection of phenol.


1995 ◽  
Vol 31 (5-6) ◽  
pp. 47-49 ◽  
Author(s):  
C. Ash ◽  
C. MacKintosh ◽  
R. MacKintosh ◽  
C. R. Fricker

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.


2020 ◽  
Vol 17 (11) ◽  
pp. 1380-1392
Author(s):  
Emine Merve Güngör ◽  
Mehlika Dilek Altıntop ◽  
Belgin Sever ◽  
Gülşen Akalın Çiftçi

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.


2020 ◽  
Vol 16 (5) ◽  
pp. 793-804
Author(s):  
Naimeh Mahheidari ◽  
Jamal Rashidiani ◽  
Hamid Kooshki ◽  
Khadijeh Eskandari

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.


2020 ◽  
Vol 16 (5) ◽  
pp. 816-828
Author(s):  
Gurdeep Rattu ◽  
Nishtha Khansili ◽  
Prayaga M. Krishna

Background: Cerium oxide nanoparticles (nanoceria) are efficient free-radical scavengers due to their dual valence state and thus exhibit optical and catalytic properties. Therefore, the main purpose of this work was to understand the peroxidase mimic activity of polymer-stabilized nanoceria for enzyme-less H2O2 sensing by fluorescence spectrometer. Objective: This research revealed the development of fluorescence hydrogen peroxide nanosensor based on the peroxidase-like activity of polyacrylic acid stabilized nanoceria (PAA-CeO2 Nps). Methods: PAA-CeO2 Nps were synthesized by simple cross-linking reaction at a low temperature and characterized by XRD, SEM, Zeta potential, TGA, FT-IR and UV-VIS spectroscopic analysis. H2O2 sensing was performed by a fluorescence spectrometer. Results:: The synthesized polymer nanocomposite was characterized by XRD, SEM, TGA, FT-IR and UV-VIS spectroscopic analysis. The XRD diffraction patterns confirmed the polycrystalline nature and SEM micrograph showed nanoparticles having hexagonal symmetry and crystallite size of 32 nm. The broad peak of Ce–O bond appeared at 508 cm-1. UV-VIS measurements revealed a welldefined absorbance peak around 315 nm and an optical band-gap of 3.17 eV. As synthesized PAACeO2 Nps effectively catalysed the decomposition of hydrogen peroxide (H2O2) into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. Under optimized conditions, the linear range for determination of hydrogen peroxide was 0.01 - 0.2 mM with a limit of detection (LOD) of 1.2 μM. Conclusion: The proposed method is ideally suited for the sensing of H2O2 at a low cost and this detection system enabled the sensing of analytes (sugars), which can enzymatically generate hydrogen peroxide.


2010 ◽  
Vol 2 (3) ◽  
pp. 207-222 ◽  
Author(s):  
Fausto Gallucci ◽  
Angelo Basile ◽  
Adolfo Iulianelli ◽  
Hans J.A.M. Kuipers

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