We report here the detection of aqueous ammonia using cobalt phthalocyanine (CoPc) and iodine dop... more We report here the detection of aqueous ammonia using cobalt phthalocyanine (CoPc) and iodine doped polyaniline (I-PANI) as active layers associated to surface acoustic wave (SAW) sensor. Cobalt phthalocyanine films were deposited on the gold sensing layer of SAW sensor platform by molecular beam epitaxy (MBE), while iodine doped polyaniline films were elaborated by Plasma Enhanced Chemical Vapor Deposition (PECVD). The functionalized SAW surfaces have been characterized by means of atomic force microscopy and by X-ray fluorescence. The two realized chemsensors have been tested and compared in terms of sensitivity and detection limit. This work demonstrates successful strategies for the fabrication of a reliable SAW sensor able to detect small molecules.
Surface acoustic wave (SAW) sensors are versatile devices, as they can be used to sensing tempera... more Surface acoustic wave (SAW) sensors are versatile devices, as they can be used to sensing temperature, pressure, strain, torque or mass. Theses abilities can be extended to chemical and biological investigations by suitable functionalisation of the sensing area. Depending on the intended application, the sensitive layer which must to specifically detect the chemical or the biological analyt of interest, may be: single strand DNA, antibody, antigen proteins, self-assembled monolayers, molecularly or ionic imprinted polymers,… This presentation will focus on some chemical and biological applications we have developed, to highlight the potential of this kind of sensors.
The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an ... more The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an aqueous solution at room temperature. The physical properties of NiMoO4 are investigated using several techniques, such as X-ray diffraction (XRD), which perfectly fits the crystalline α-form of NiMoO4. Moreover, scanning electron microscope (SEM) images show nanosheet-like particles. The atomic force microscopy (AFM) measurements reveal high roughness of the particle’s surface. Furthermore, the investigations into the main electronic levels of α-NiMoO4 suggest a strong UV–visible light absorption. The optical band gap is found to be about 2.36 eV. Then, the photocatalytic activity of the synthesized NiMoO4 nanoparticles (NPs) is tested against methylene blue (MB) dye as a pollutant model. The obtained results reveal good capacity of MB degradation even in the dark. It exhibits a degradation efficiency up to 87% within 60 min, under visible-light illumination, and 44% in the dark. The photocatalytic stability of NiMoO4 NPs is studied as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.
Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 4, 4′-diaminodi... more Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 4, 4′-diaminodiphenyl (44′DDS) and 3, 3′-diaminodiphenyl (33′DDS) sulfone diamines crosslinking hardeners. The structural, linear optical and mechanical properties of the investigated sample were analysed. Dynamic Mechanical Thermal Analysis and wide-angle x-ray diffraction were conducted to select a candidate presenting interesting thermo-mechanical properties and particular nanostructures embedded in an amorphous matrix. Our choice is therefore focused on DGEBA/33′DDS polymer for which, rocking curve measurements revealed the existence of two principal reflecting planes inclined to each other by about 0.27°. To highlight the potential effect of these interfaces, Thermally Stimulated Depolarization Current (TSDC) and Time Domain Spectroscopy measurements have been carried out. The application of the windowing polarization TSDC technique, in DGEBA/33′DDS polymer sample, gives an almost linear variation...
Modeling a Surface Acoustic Wave (SAW) sensor response as a chemosensor and not only as just an e... more Modeling a Surface Acoustic Wave (SAW) sensor response as a chemosensor and not only as just an electronic transducer was performed with COMSOL Multiphysics. For this study, the SAW’s sensing area was functionalized with an ionic imprinted polymer (IIP), designed for the selective detection of lead ions. The idea consists in subdividing the IIP into elementary blocks whose physical properties can be modified separately. Three configurations have been envisaged: the IIP before and after lead ions extraction and the non-imprinted polymer (NIP). The generation of shear-horizontal waves on LiTaO3 piezoelectric substrate is confirmed by recording the displacement amplitude versus time, according to the three space directions. The sensors sensitivity is estimated from the delays induced by the incorporation of the lead ions in the IIP layer. To the best of our knowledge, this approach has never been presented in the literature.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
The growth of low temperature GaN (LT-GaN) layers on GaAs (0 0 1) substrate was performed by meta... more The growth of low temperature GaN (LT-GaN) layers on GaAs (0 0 1) substrate was performed by metal organic vapor phase epitaxy (MOVPE) at growth temperature range of 500-800 °C. Laser reflectometry (LR) was employed for in situ monitoring of all growth steps. The simulation of experimental time reflectance traces shows that at the first growth stage, the surface roughness increases to reach a limit value depending on growth temperature. Due to surface roughness profile the growth rate time-dependence was found non negligible at the first growth stage. The investigations of in situ reflectance give more precise measurement of growth rates that yields to thermal activation energy close to 0.12 eV. The ex-situ analyses by spectral reflectance (SR) and Atomic Force Microscopy (AFM) showed that the better surface morphology was obtained when the GaN buffer layer is grown at lower temperature, while three dimensional (3D) growth mode was observed at higher temperature. A series of high temperature (800 °C) GaN (HT-GaN) layers were grown on different thicknesses of low temperature (550 °C) GaN buffer layer. The results showed that high density of nucleation sites enhances the initial growth rate and improves the morphological quality of GaN active layer.
In this study, a surface acoustic wave (SAW) biosensor has been investigated to quantify the affi... more In this study, a surface acoustic wave (SAW) biosensor has been investigated to quantify the affinity and to estimate the binding kinetic between tumor necrosis factor α (TNF-α) and its inhibitor: SPD-304. To the best of our knowledge this is first ever report on real time and label free monitoring of TNF-α/ SPD-304 affinity. Effects of the SPD-304 solvent and DMSO cosolvent on TNFα/SPD-304 interaction have been investigated. Gravimetric results indicate that the limit of detection (LOD) of the developed biosensor was of order of 10 nM and that DMSO cosolvent influences the kinetic of interaction, the saturation value, and thus the value of the dissociation constant (Kd) of the TNF-α / SPD-304 system.
Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastro... more Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastrointestinal ulcers and may gradually lead to gastric cancer. H. pylori expresses the outer membrane HopQ protein at the earliest stages of infection. Therefore, HopQ is a highly reliable candidate as a biomarker for H. pylori detection in saliva samples. In this work, an H. pylori immunosensor is based on detecting HopQ as an H. pylori biomarker in saliva. The immunosensor was developed by surface modification of screen-printed carbon electrodes (SPCE) with MWCNT-COOH decorated with gold nanoparticles (AuNP) followed by HopQ capture antibody grafting on SPCE/MWCNT/AuNP surface using EDC/S-NHS chemistry. The sensor performance was investigated utilizing various methods, such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX). H. pylori detection performance in spiked saliva...
Background Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can c... more Background Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastrointestinal ulcers and may gradually lead to gastric cancer. H. pylori expresses the outer membrane HopQ protein at the earliest stages of infection. Therefore, HopQ is a highly reliable candidate as a biomarker for H. pylori detection in saliva samples. Materials and Methods: An H. pylori immunosensor is developed based on detecting HopQ as a biomarker in saliva by a screen-printed carbon electrode (SPCE) modified with MWCNT-COOH decorated with gold nanoparticles (AuNP). The HopQ antibodies are grafted on the SPCE/MWCNT/AuNP surface using EDC/S-NHS chemistry. The sensor performance is investigated by various methods and H. pylori detection performance in spiked saliva samples is evaluated by square wave voltammetry. Results: The sensor is suitable for HopQ detection with high sensitivity and excellent linearity in the 10 pg/mL - 100 ng/mL range and with a 10 pg/ml limit of det...
A 104 MHz Surface Acoustic Wave (SAW) sensor functionalized with a 100 nm thick Cobalt Phthalocya... more A 104 MHz Surface Acoustic Wave (SAW) sensor functionalized with a 100 nm thick Cobalt Phthalocyanine (CoPc) layer was investigated for chloride sensing in liquid media. Atomic force microscopy was first investigated to characterize the morphology of three phthalocyanine molecules, Pc, CoPc and FePc, deposited by molecular beam epitaxy on the SAW sensing area. CoPc was chosen for its particular columnar shape, highly suitable for sensing applications. Gravimetric results indicate that the Limit of Detection (LOD) of the developed CoPc-SAW sensor was of order of 0.2 μM, and that the corresponding sensitivity was equal to (0.148 ± 0.001) °μM-1. Recognition and release average time constants were estimated at (45 ± 7) s and (74 ± 4) s respectively.
The data presented here are related to the article entitled “New contributions to the drug profil... more The data presented here are related to the article entitled “New contributions to the drug profile of TNFα inhibitor SPD304: affinity, selectivity ADMET considerations” published in the European Journal of pharmacology. As DMSO is usually used as a co-solvent to dissolve low aqueous soluble small molecules, such as SPD304, we have investigated the influence of its concentration on the kinetic of interaction between tumor necrosis factor α (TNF-α) and its inhibitor, SPD304. The presented data, acquired using a surface acoustic wave sensor, can be used in further biological studies to compare the kinetic of interaction between proteins/small molecules in general and TNFα/inhibitors in particular. The estimated dissociation constant can be compared to other ones to statute on the degree of affinity between a protein and a given molecule.
We report here the detection of aqueous ammonia using cobalt phthalocyanine (CoPc) and iodine dop... more We report here the detection of aqueous ammonia using cobalt phthalocyanine (CoPc) and iodine doped polyaniline (I-PANI) as active layers associated to surface acoustic wave (SAW) sensor. Cobalt phthalocyanine films were deposited on the gold sensing layer of SAW sensor platform by molecular beam epitaxy (MBE), while iodine doped polyaniline films were elaborated by Plasma Enhanced Chemical Vapor Deposition (PECVD). The functionalized SAW surfaces have been characterized by means of atomic force microscopy and by X-ray fluorescence. The two realized chemsensors have been tested and compared in terms of sensitivity and detection limit. This work demonstrates successful strategies for the fabrication of a reliable SAW sensor able to detect small molecules.
Surface acoustic wave (SAW) sensors are versatile devices, as they can be used to sensing tempera... more Surface acoustic wave (SAW) sensors are versatile devices, as they can be used to sensing temperature, pressure, strain, torque or mass. Theses abilities can be extended to chemical and biological investigations by suitable functionalisation of the sensing area. Depending on the intended application, the sensitive layer which must to specifically detect the chemical or the biological analyt of interest, may be: single strand DNA, antibody, antigen proteins, self-assembled monolayers, molecularly or ionic imprinted polymers,… This presentation will focus on some chemical and biological applications we have developed, to highlight the potential of this kind of sensors.
The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an ... more The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an aqueous solution at room temperature. The physical properties of NiMoO4 are investigated using several techniques, such as X-ray diffraction (XRD), which perfectly fits the crystalline α-form of NiMoO4. Moreover, scanning electron microscope (SEM) images show nanosheet-like particles. The atomic force microscopy (AFM) measurements reveal high roughness of the particle’s surface. Furthermore, the investigations into the main electronic levels of α-NiMoO4 suggest a strong UV–visible light absorption. The optical band gap is found to be about 2.36 eV. Then, the photocatalytic activity of the synthesized NiMoO4 nanoparticles (NPs) is tested against methylene blue (MB) dye as a pollutant model. The obtained results reveal good capacity of MB degradation even in the dark. It exhibits a degradation efficiency up to 87% within 60 min, under visible-light illumination, and 44% in the dark. The photocatalytic stability of NiMoO4 NPs is studied as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.
Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 4, 4′-diaminodi... more Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 4, 4′-diaminodiphenyl (44′DDS) and 3, 3′-diaminodiphenyl (33′DDS) sulfone diamines crosslinking hardeners. The structural, linear optical and mechanical properties of the investigated sample were analysed. Dynamic Mechanical Thermal Analysis and wide-angle x-ray diffraction were conducted to select a candidate presenting interesting thermo-mechanical properties and particular nanostructures embedded in an amorphous matrix. Our choice is therefore focused on DGEBA/33′DDS polymer for which, rocking curve measurements revealed the existence of two principal reflecting planes inclined to each other by about 0.27°. To highlight the potential effect of these interfaces, Thermally Stimulated Depolarization Current (TSDC) and Time Domain Spectroscopy measurements have been carried out. The application of the windowing polarization TSDC technique, in DGEBA/33′DDS polymer sample, gives an almost linear variation...
Modeling a Surface Acoustic Wave (SAW) sensor response as a chemosensor and not only as just an e... more Modeling a Surface Acoustic Wave (SAW) sensor response as a chemosensor and not only as just an electronic transducer was performed with COMSOL Multiphysics. For this study, the SAW’s sensing area was functionalized with an ionic imprinted polymer (IIP), designed for the selective detection of lead ions. The idea consists in subdividing the IIP into elementary blocks whose physical properties can be modified separately. Three configurations have been envisaged: the IIP before and after lead ions extraction and the non-imprinted polymer (NIP). The generation of shear-horizontal waves on LiTaO3 piezoelectric substrate is confirmed by recording the displacement amplitude versus time, according to the three space directions. The sensors sensitivity is estimated from the delays induced by the incorporation of the lead ions in the IIP layer. To the best of our knowledge, this approach has never been presented in the literature.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
The growth of low temperature GaN (LT-GaN) layers on GaAs (0 0 1) substrate was performed by meta... more The growth of low temperature GaN (LT-GaN) layers on GaAs (0 0 1) substrate was performed by metal organic vapor phase epitaxy (MOVPE) at growth temperature range of 500-800 °C. Laser reflectometry (LR) was employed for in situ monitoring of all growth steps. The simulation of experimental time reflectance traces shows that at the first growth stage, the surface roughness increases to reach a limit value depending on growth temperature. Due to surface roughness profile the growth rate time-dependence was found non negligible at the first growth stage. The investigations of in situ reflectance give more precise measurement of growth rates that yields to thermal activation energy close to 0.12 eV. The ex-situ analyses by spectral reflectance (SR) and Atomic Force Microscopy (AFM) showed that the better surface morphology was obtained when the GaN buffer layer is grown at lower temperature, while three dimensional (3D) growth mode was observed at higher temperature. A series of high temperature (800 °C) GaN (HT-GaN) layers were grown on different thicknesses of low temperature (550 °C) GaN buffer layer. The results showed that high density of nucleation sites enhances the initial growth rate and improves the morphological quality of GaN active layer.
In this study, a surface acoustic wave (SAW) biosensor has been investigated to quantify the affi... more In this study, a surface acoustic wave (SAW) biosensor has been investigated to quantify the affinity and to estimate the binding kinetic between tumor necrosis factor α (TNF-α) and its inhibitor: SPD-304. To the best of our knowledge this is first ever report on real time and label free monitoring of TNF-α/ SPD-304 affinity. Effects of the SPD-304 solvent and DMSO cosolvent on TNFα/SPD-304 interaction have been investigated. Gravimetric results indicate that the limit of detection (LOD) of the developed biosensor was of order of 10 nM and that DMSO cosolvent influences the kinetic of interaction, the saturation value, and thus the value of the dissociation constant (Kd) of the TNF-α / SPD-304 system.
Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastro... more Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastrointestinal ulcers and may gradually lead to gastric cancer. H. pylori expresses the outer membrane HopQ protein at the earliest stages of infection. Therefore, HopQ is a highly reliable candidate as a biomarker for H. pylori detection in saliva samples. In this work, an H. pylori immunosensor is based on detecting HopQ as an H. pylori biomarker in saliva. The immunosensor was developed by surface modification of screen-printed carbon electrodes (SPCE) with MWCNT-COOH decorated with gold nanoparticles (AuNP) followed by HopQ capture antibody grafting on SPCE/MWCNT/AuNP surface using EDC/S-NHS chemistry. The sensor performance was investigated utilizing various methods, such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX). H. pylori detection performance in spiked saliva...
Background Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can c... more Background Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastrointestinal ulcers and may gradually lead to gastric cancer. H. pylori expresses the outer membrane HopQ protein at the earliest stages of infection. Therefore, HopQ is a highly reliable candidate as a biomarker for H. pylori detection in saliva samples. Materials and Methods: An H. pylori immunosensor is developed based on detecting HopQ as a biomarker in saliva by a screen-printed carbon electrode (SPCE) modified with MWCNT-COOH decorated with gold nanoparticles (AuNP). The HopQ antibodies are grafted on the SPCE/MWCNT/AuNP surface using EDC/S-NHS chemistry. The sensor performance is investigated by various methods and H. pylori detection performance in spiked saliva samples is evaluated by square wave voltammetry. Results: The sensor is suitable for HopQ detection with high sensitivity and excellent linearity in the 10 pg/mL - 100 ng/mL range and with a 10 pg/ml limit of det...
A 104 MHz Surface Acoustic Wave (SAW) sensor functionalized with a 100 nm thick Cobalt Phthalocya... more A 104 MHz Surface Acoustic Wave (SAW) sensor functionalized with a 100 nm thick Cobalt Phthalocyanine (CoPc) layer was investigated for chloride sensing in liquid media. Atomic force microscopy was first investigated to characterize the morphology of three phthalocyanine molecules, Pc, CoPc and FePc, deposited by molecular beam epitaxy on the SAW sensing area. CoPc was chosen for its particular columnar shape, highly suitable for sensing applications. Gravimetric results indicate that the Limit of Detection (LOD) of the developed CoPc-SAW sensor was of order of 0.2 μM, and that the corresponding sensitivity was equal to (0.148 ± 0.001) °μM-1. Recognition and release average time constants were estimated at (45 ± 7) s and (74 ± 4) s respectively.
The data presented here are related to the article entitled “New contributions to the drug profil... more The data presented here are related to the article entitled “New contributions to the drug profile of TNFα inhibitor SPD304: affinity, selectivity ADMET considerations” published in the European Journal of pharmacology. As DMSO is usually used as a co-solvent to dissolve low aqueous soluble small molecules, such as SPD304, we have investigated the influence of its concentration on the kinetic of interaction between tumor necrosis factor α (TNF-α) and its inhibitor, SPD304. The presented data, acquired using a surface acoustic wave sensor, can be used in further biological studies to compare the kinetic of interaction between proteins/small molecules in general and TNFα/inhibitors in particular. The estimated dissociation constant can be compared to other ones to statute on the degree of affinity between a protein and a given molecule.
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