scholarly journals Immobilization of HRP Enzyme on Layered Double Hydroxides for Biosensor Application

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Zouhair M. Baccar ◽  
Imène Hafaiedh
Keyword(s):  
Hydrogen Peroxide ◽  
Layered Double Hydroxides ◽  
Gold Surface ◽  
Raw Milk ◽  
Good Reproducibility ◽  
Electrostatic Adsorption ◽  
Constant Ph ◽  
Biosensor Application ◽  
Limit Detection ◽  
Double Hydroxides

We present a new biosensor for hydrogen peroxide (H2O2) detection. The biosensor was based on the immobilization of horseradish peroxidase (HRP) enzyme on layered double hydroxides- (LDH-) modified gold surface. The hydrotalcite LDH (Mg2Al) was prepared by coprecipitation in constant pH and in ambient temperature. The immobilization of the peroxidase on layered hybrid materials was realized via electrostatic adsorption autoassembly process. The detection of hydrogen peroxide was successfully observed in PBS buffer with cyclic voltammetry and the chronoamperometry techniques. A limit detection of 9 μM of H2O2was obtained with a good reproducibility. We investigate the sensitivity of our developed biosensor for H2O2detection in raw milk.

Photocatalytic decolourization of methylene blue using [Zn-Al] layered double hydroxides synthesized at different molar cationic ratios

Clay Minerals ◽  
2017 ◽  
Vol 52 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Kaouther Abderrazek ◽  
Najoua Frini Srasra ◽  
Ezzeddine Srasra
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Layered Double Hydroxides ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Molar Ratios ◽  
Constant Ph ◽  
Double Hydroxides

Abstract[Zn-Al] layered double hydroxides (LDH) with cationic molar ratios of R = Zn/Al 1–5 were synthesized by the coprecipitation method at constant pH = 10. The samples synthesized and their derived forms obtained after calcination at 500°C and at 900°C (denoted Zn-Al-R, Zn-Al-R-500 and Zn-Al-R-900, respectively), were characterized by X-ray diffraction (XRD), inductively coupled plasmamass spectrometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, diffuse reflectance spectroscopy and nitrogen physisorption at −196°C. The XRD study showed: (1) the presence of accessory ZnO with the LDH in samples synthesized with R ≥ 3; and (2) the lamellar structure was destroyed at 500°C which made room for a poorly ordered ZnO phase, while calcination at 900°C yielded well crystallized ZnO and ZnAl2O4. The photocatalytic activity of the calcined and the unheated samples was evaluated for the decolourization of methylene blue. The photocatalytic activity was dependent on the cationic ratio R and on the calcination temperature. The sample Zn-Al-3 displayed maximum photocatalytic activity. Calcination at 500 and 900°C improved the photocatalytic activity of LDH synthesized at R = 1 and 2.

scholarly journals Synthesis of hybrid materials based on layered double hydroxides

2019 ◽  
pp. 4-10
Author(s):  
Olga Nestroinaia ◽  
Oksana Ponomarenko
Keyword(s):  
Hybrid Materials ◽  
Layered Double Hydroxides ◽  
Microwave Method ◽  
Hydrothermal Conditions ◽  
Promising Direction ◽  
X Ray ◽  
Constant Ph ◽  
Co Precipitation ◽  
Double Hydroxides ◽  
Scanning Electron

The use of pesticides adversely affects not only the environment, but also human health. A promising direction in solving this problem is to obtain hybrid materials capable of controlled release of pesticides. Layered double hydroxides (LDHs) can act as a matrix. Layered double hydroxides with intercalated glyphosate anions (MgAl-Gly-LDH) were synthesized by different methods: coprecipitation at constant pH (MgAl-Gly-LDH-c), synthesis under hydrothermal conditions (MgAl-Gly-LDH-ht), microwave method (MgAl-Gly-LDH-mw) and rehydration method (MgAl-Gly-LDH-re). All the synthesized samples were analyzed by X-ray phase analysis (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. It is shown that the methods of co-precipitation and synthesis under hydrothermal conditions are most suitable for the synthesis of hybrid materials. Samples of MgAl-Gly-LDH-ht and MgAl-Gly-LDH-c have a well-crystallized structure, unlike the sample of MgAl-Gly-LDH-re, in which the LDH phase is practically absent.

scholarly journals Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
H. Baccar ◽  
T. Ktari ◽  
A. Abdelghani
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Detection Limit ◽  
Horseradish Peroxidase ◽  
Palladium Nanoparticles ◽  
Gold Electrode ◽  
Volume Ratio ◽  
Gold Surface ◽  
Amino Groups ◽  
Limit Detection

We present a comparison between two biosensors for hydrogen peroxide (H2O2) detection. The first biosensor was developed by the immobilization of Horseradish Peroxidase (HRP) enzyme on thiol-modified gold electrode. The second biosensor was developed by the immobilization of cysteamine functionalizing palladium nanoparticles on modified gold surface. The amino groups can be activated with glutaraldehyde for horseradish peroxidase immobilization. The detection of hydrogen peroxide was successfully observed in PBS for both biosensors using the cyclic voltammetry and the chronoamperometry techniques. The results show that the limit detection depends on the large surface-to-volume ratio attained with palladium nanoparticles. The second biosensor presents a better detection limit of 7.5 μM in comparison with the first one which is equal to 75 μM.

Determination of alizarin red S based on layered double hydroxides-improved chemiluminescence from hydrogen peroxide and luminol

2017 ◽  
Vol 9 (46) ◽  
pp. 6468-6473 ◽  
Author(s):  
Feng Pan ◽  
Yilin Zhang ◽  
Zhiqin Yuan ◽  
Chao Lu
Keyword(s):  
Hydrogen Peroxide ◽  
Layered Double Hydroxides ◽  
Alizarin Red S ◽  
Alizarin Red ◽  
Double Hydroxides

Selective alizarin red S detection based on the layered double hydroxides-improved chemiluminescence from hydrogen peroxide and luminol is presented.

scholarly journals Layered double hydroxides: matrices for storage and source of boron for plant growth

Clay Minerals ◽  
2018 ◽  
Vol 53 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Gustavo Franco de Castro ◽  
Jader Alves Ferreira ◽  
Denise Eulálio ◽  
Silas Junior de Souza ◽  
Sarah Vieira Novais ◽  
...  
Keyword(s):  
Plant Growth ◽  
Layered Double Hydroxides ◽  
Dry Matter ◽  
Statistical Difference ◽  
Crop Productivity ◽  
Absorption Efficiency ◽  
Basal Spacing ◽  
Plant Yield ◽  
Constant Ph ◽  
Double Hydroxides

ABSTRACTThe increase of the absorption efficiency of boron (B) by plants is essential for increasing crop productivity. The intercalation of B in MgAl layered double hydroxides (LDHs) is an alternative to evaluating how these materials can provide B to plants. In this work, a MgAl LDH intercalated with borate ions (Mg2Al-B-LDH) was synthesized by the constant pH coprecipitation method, and the material produced was evaluated as a matrix for storage and as a source of B for plants. The Mg2Al-B-LDH was characterized by XRD, ATR-FTIR, TGA-DTA, specific surface area, pore size and volume, and SEM. A bioassay was performed to verify the supply of B to plants from the two sources in the forms of H3BO3 and of Mg2Al-B-LDH to sunflower plants grown in pots. The LDH basal spacing value of 12.0 Å is characteristic of intercalation of tetraborate octahydrate ions [B4O5(OH)42−]·8H2O between the layers. There was an increase in the dry matter (DM) and B content of the plants relative to those treatments where no B was added. The lack of statistical difference for plant yield between the two sources of B suggests a lack of stability of the Mg2Al-B-LDH structure under the acidic condition of the soil.

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