R. Mlika - Academia.edu (original) (raw)
Papers by R. Mlika
Journal of Molecular Structure, 2011
A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recogni... more A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recognition. The complexation properties of this ligand towards transition metal ions have been investigated by UV–Visible and fluorescence spectroscopies. It has been found that the ligand has remarkable complexation ability for transition metal Ni2+, Co2+, Hg2+, heavy metal ions Al3+ and Pb2+ with an exceptional high affinity for the
Synthetic Metals
Abstract In this work, a non-covalent nanocomposite based on iron (III) porphyrin derivate (Fe(II... more Abstract In this work, a non-covalent nanocomposite based on iron (III) porphyrin derivate (Fe(III)TMPP) and thermally reduced graphene oxide (TRGO) has been prepared. A membrane based on this nanocomposite TRGO/Fe(III)TMPP was deposited on Au electrode and has been characterized by ultraviolet–visible spectroscopy (UV–vis), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS). The results indicated that the TRGO exhibits a good interaction and a high conductivity with the Fe(III)TMPP molecules. This membrane has been applied as electrochemical platform for Bisphenol A (BPA) detection. It has showed a linear response towards these molecules with a high detection limit of 2.1 10−13 M. In addition, the proposed sensor has revealed a high selectivity and reproducibility. This sensor has been applied for the electrochemical detection of BPA in Milk sample with satisfying results.
Theoretical Chemistry Accounts
Sensors and Actuators B: Chemical, 2016
Materials Science and Engineering: C, 2011
ABSTRACT In this work, we report the impedance spectroscopic investigation of the effect of the t... more ABSTRACT In this work, we report the impedance spectroscopic investigation of the effect of the thin film type on the selectivity of gold/azo-calix[4]arene electrodes. For this purpose, two C1 and C3 azo-calix[4]arene derivative molecules, used as thin films, are deposited by spin-coating process on the gold surface. These thin films were first studied using contact angle measurements. This revealed a less hydrophobic character for C3 thin film, which has been attributed to the presence of hydroxyl groups at the lower rim.The sensitivity study, by Electrochemical Impedance Spectroscopy (EIS), towards Cu2+ and Eu3+ cations, has showed that the C3 thin film is more sensitive and selective towards Eu3+ than C1. This best performance is due to the presence of two ester groups acting as clips and leading to more complexation stability.The EIS results were modeled by an appropriate equivalent circuit for the aim of elucidating electrical properties of thin films. This modeling has exposed that C3 thin film presents lower ionic conductivity and limited diffusion phenomenon at the interface.
Synthetic Metals, 2015
ABSTRACT We report on the investigation of the surface morphology, optical and electrical propert... more ABSTRACT We report on the investigation of the surface morphology, optical and electrical properties of nanocompsite films from multiwalled carbon nanotubes (MWCNT) dispersed in nickel phthalocyanine (NiPc) with different amounts. We have explored the surface morphology of the films by using fractal concepts. The NiPc:MWCNT films were found to have a fractal dimension of ca. 2, indicating a quasi Euclidean surface. An increase in the wetting contact angle of NiPc:MWCNT films with MWCNT concentrations was observed. AC conductivity and dielectric properties of NiPc:MWCNT nanohybrids were measured at 100 Hz–13 MHz at room temperature. Upon increasing the concentration of MWCNT an increase in the AC conductivity is observed. The variation of AC conductivity with frequency has been described by the power law. The introduction of the concept of Constant Phase Element into the equivalent circuit model gave a fit in good agreement with the experimental data and implied the influence of a fractal interface on the real capacitance. The evolution of the electrical parameters with frequency and bias voltage of these composite-based systems has been discussed. Finally, the optimum composite proportion for high electrode sensitivity was tested by means of the electrochemical impedance spectroscopy for detection of Bisphenol A.
International Journal of Inorganic Materials, 2000
Polysiloxane membranes containing specific receptor molecules (i.e., 2,9-(o-methoxy)-phenoxydecan... more Polysiloxane membranes containing specific receptor molecules (i.e., 2,9-(o-methoxy)-phenoxydecane dicarboxylic acid, aand b-cyclodextrin) are used in the preparation of electrolyte insulator semiconductor (EIS) devices. Polysiloxane-gel matrices were 31 characterized by spectroscopic methods. Ion sensitivity and selectivity of EIS devices to different ionic species have been tested for Fe , 21 21 Pb and Cd ions in aqueous solution. The results show a super-Nernstian response for dispersed AE / polysiloxane (DS-AE / PS) film 31 21 to Fe ions. A Nernstian response was observed for linked CD/ polysiloxane (LK-CD/ PS) film to heavy metal ions (i.e., Pb and 21 21 21 21 Cd). LK-(a)CD/ PS shows a good affinity to Cd ions (28 mV/ pCd
Synthetic Metals, 1997
The organic supramolecular compound synthesized from pyrochatechoi units bound in the o~-position... more The organic supramolecular compound synthesized from pyrochatechoi units bound in the o~-position of a linear dicarboxylic acid (AE6) previously used as a stable chelate iron(III) in solution is applied in this work as an ionophoric reagent on ion-sensitive field-effect transistor (ISFET) and electrolyte-insulator-semiconductor (EIS) structures for iron detection. The surface gate ox!de (SiO2! sensit!zatign of sensors was performed, using three deposition methods: chemicalgraf{ingto obtain~ AE6 monolayer, deposition by vacuum sublimation of an AE6 thin fihn and incorporation in a polysiloxane gel membrane. Classical electrochemical measurements were made to test the sensitivity towards iron of the AE6 membranes, in EIS and ISFET structures. A Nernstian sensitivity, a good selectivity and a long lifetime were obtained for the evaporated layer and the gel membranes. @ 1997 Elsevier Science S.A.
Sensors and Actuators B: Chemical, 2000
Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the fun... more Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the functionalization of ISFET microsensors and EIS structures through thermal evaporation process. Both calixarenes have shown a nernstian sensitivity over three decades towards only copper (II) activities. Very low selectivity coefficients were observed for K+ and Ca2+ whereas Cd2+ and Pb2+ (less than 10−3) can be
Sensors and Actuators B: Chemical, 1998
Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporat... more Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporation under vacuum to fabricate chemical ion-selective field effect transistor (ISFET) microsensors. A high-performance liquid-phase chromatography (HPLC) method was used to verify the non-degradation of the calixarene layers, after the evaporation process. The sensing properties of these ionophores towards alkaline and heavy metal ions were tested. Both devices
Sensors and Actuators B: Chemical, 2007
ABSTRACT Thin films of two partially benzylated β-CDs (β-cyclodextrins) were used to functionaliz... more ABSTRACT Thin films of two partially benzylated β-CDs (β-cyclodextrins) were used to functionalize ITO (indium tin oxide) and Si/SiO2 substrates which were deposited by spin coating technique, to fabricate respectively a diode device and an EIS (electrolyte–insulator–semiconductor) sensor. We have studied electrical properties of ITO/β-CDs (Bz)n=5,10/Al diodes by means of current–voltage measurement and impedance spectroscopy. The application of these new modified β-CD (Bz)n=5,10 in the field of chemical sensors has been studied. Electrochemical capacitance measurements with EIS structures were made to test and calibrate physico-chemical sensors with regards to their sensitivity and selectivity. The sensing properties of these partial benzylated β-CD films towards Pb2+ in aqueous solution for sensor application were tested.A significant effect of the average of benzylation degree on both electrical and sensing properties has been investigated.
Sensors and Actuators A: Physical, 1999
The large interfacial area of the porous silicon is used as ion sensitive membrane support. The p... more The large interfacial area of the porous silicon is used as ion sensitive membrane support. The porous layer is oxidized by Rapid Thermal Oxidation (RTO) technique and a calix(4)arene layer was evaporated under vacuum. The structure is then used as the working electrode of an electrochemical cell and sensor properties were investigated by capacitance measurements. We observed an over-Nernstian response
Sensor Letters, 2009
... R. Mlika1∗, H. Yousfi2, B. Bouchikhi2, I. Dumazet-Bonnamour3, N. Jaffrezic-Renault4∗, and H. ... more ... R. Mlika1∗, H. Yousfi2, B. Bouchikhi2, I. Dumazet-Bonnamour3, N. Jaffrezic-Renault4∗, and H. Ben Ouada1 ... In this objective, a large variety of receptors and transducers were used for sensors applications.14 During the last decades, the use of calixarenes as sen-sitive part of ...
Mechanisms of Development, 1998
XLPOU91, a POU-homeobox gene is expressed in a narrow window during early Xenopus development. We... more XLPOU91, a POU-homeobox gene is expressed in a narrow window during early Xenopus development. We show that ectopic expression of XLPOU91 RNA causes severe posterior truncations in embryos without inhibiting the formation of Spemann's organizer. Ectopic XLPOU91 expression also inhibits mesoderm induction by fibroblast growth factor (FGF) and activin in animal cap explants. Using antisense RNA, we depleted endogenous XLPOU91 protein in animal caps. Gastrula-stage animal caps expressing XLPOU91 antisense RNA do not lose competence to FGF, unlike controls, these animal caps express XBra after FGF treatment. Endogenous XLPOU91 levels are peaking when FGF mesoderm-inducing competence is lost in animal caps. Thus XLPOU91 protein may act as a competence switch during early development, as XLPOU91 levels increase in the embryo, the mesoderm response to FGF is lost.
Journal of Molecular Structure, 2011
A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recogni... more A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recognition. The complexation properties of this ligand towards transition metal ions have been investigated by UV–Visible and fluorescence spectroscopies. It has been found that the ligand has remarkable complexation ability for transition metal Ni2+, Co2+, Hg2+, heavy metal ions Al3+ and Pb2+ with an exceptional high affinity for the
Synthetic Metals
Abstract In this work, a non-covalent nanocomposite based on iron (III) porphyrin derivate (Fe(II... more Abstract In this work, a non-covalent nanocomposite based on iron (III) porphyrin derivate (Fe(III)TMPP) and thermally reduced graphene oxide (TRGO) has been prepared. A membrane based on this nanocomposite TRGO/Fe(III)TMPP was deposited on Au electrode and has been characterized by ultraviolet–visible spectroscopy (UV–vis), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS). The results indicated that the TRGO exhibits a good interaction and a high conductivity with the Fe(III)TMPP molecules. This membrane has been applied as electrochemical platform for Bisphenol A (BPA) detection. It has showed a linear response towards these molecules with a high detection limit of 2.1 10−13 M. In addition, the proposed sensor has revealed a high selectivity and reproducibility. This sensor has been applied for the electrochemical detection of BPA in Milk sample with satisfying results.
Theoretical Chemistry Accounts
Sensors and Actuators B: Chemical, 2016
Materials Science and Engineering: C, 2011
ABSTRACT In this work, we report the impedance spectroscopic investigation of the effect of the t... more ABSTRACT In this work, we report the impedance spectroscopic investigation of the effect of the thin film type on the selectivity of gold/azo-calix[4]arene electrodes. For this purpose, two C1 and C3 azo-calix[4]arene derivative molecules, used as thin films, are deposited by spin-coating process on the gold surface. These thin films were first studied using contact angle measurements. This revealed a less hydrophobic character for C3 thin film, which has been attributed to the presence of hydroxyl groups at the lower rim.The sensitivity study, by Electrochemical Impedance Spectroscopy (EIS), towards Cu2+ and Eu3+ cations, has showed that the C3 thin film is more sensitive and selective towards Eu3+ than C1. This best performance is due to the presence of two ester groups acting as clips and leading to more complexation stability.The EIS results were modeled by an appropriate equivalent circuit for the aim of elucidating electrical properties of thin films. This modeling has exposed that C3 thin film presents lower ionic conductivity and limited diffusion phenomenon at the interface.
Synthetic Metals, 2015
ABSTRACT We report on the investigation of the surface morphology, optical and electrical propert... more ABSTRACT We report on the investigation of the surface morphology, optical and electrical properties of nanocompsite films from multiwalled carbon nanotubes (MWCNT) dispersed in nickel phthalocyanine (NiPc) with different amounts. We have explored the surface morphology of the films by using fractal concepts. The NiPc:MWCNT films were found to have a fractal dimension of ca. 2, indicating a quasi Euclidean surface. An increase in the wetting contact angle of NiPc:MWCNT films with MWCNT concentrations was observed. AC conductivity and dielectric properties of NiPc:MWCNT nanohybrids were measured at 100 Hz–13 MHz at room temperature. Upon increasing the concentration of MWCNT an increase in the AC conductivity is observed. The variation of AC conductivity with frequency has been described by the power law. The introduction of the concept of Constant Phase Element into the equivalent circuit model gave a fit in good agreement with the experimental data and implied the influence of a fractal interface on the real capacitance. The evolution of the electrical parameters with frequency and bias voltage of these composite-based systems has been discussed. Finally, the optimum composite proportion for high electrode sensitivity was tested by means of the electrochemical impedance spectroscopy for detection of Bisphenol A.
International Journal of Inorganic Materials, 2000
Polysiloxane membranes containing specific receptor molecules (i.e., 2,9-(o-methoxy)-phenoxydecan... more Polysiloxane membranes containing specific receptor molecules (i.e., 2,9-(o-methoxy)-phenoxydecane dicarboxylic acid, aand b-cyclodextrin) are used in the preparation of electrolyte insulator semiconductor (EIS) devices. Polysiloxane-gel matrices were 31 characterized by spectroscopic methods. Ion sensitivity and selectivity of EIS devices to different ionic species have been tested for Fe , 21 21 Pb and Cd ions in aqueous solution. The results show a super-Nernstian response for dispersed AE / polysiloxane (DS-AE / PS) film 31 21 to Fe ions. A Nernstian response was observed for linked CD/ polysiloxane (LK-CD/ PS) film to heavy metal ions (i.e., Pb and 21 21 21 21 Cd). LK-(a)CD/ PS shows a good affinity to Cd ions (28 mV/ pCd
Synthetic Metals, 1997
The organic supramolecular compound synthesized from pyrochatechoi units bound in the o~-position... more The organic supramolecular compound synthesized from pyrochatechoi units bound in the o~-position of a linear dicarboxylic acid (AE6) previously used as a stable chelate iron(III) in solution is applied in this work as an ionophoric reagent on ion-sensitive field-effect transistor (ISFET) and electrolyte-insulator-semiconductor (EIS) structures for iron detection. The surface gate ox!de (SiO2! sensit!zatign of sensors was performed, using three deposition methods: chemicalgraf{ingto obtain~ AE6 monolayer, deposition by vacuum sublimation of an AE6 thin fihn and incorporation in a polysiloxane gel membrane. Classical electrochemical measurements were made to test the sensitivity towards iron of the AE6 membranes, in EIS and ISFET structures. A Nernstian sensitivity, a good selectivity and a long lifetime were obtained for the evaporated layer and the gel membranes. @ 1997 Elsevier Science S.A.
Sensors and Actuators B: Chemical, 2000
Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the fun... more Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the functionalization of ISFET microsensors and EIS structures through thermal evaporation process. Both calixarenes have shown a nernstian sensitivity over three decades towards only copper (II) activities. Very low selectivity coefficients were observed for K+ and Ca2+ whereas Cd2+ and Pb2+ (less than 10−3) can be
Sensors and Actuators B: Chemical, 1998
Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporat... more Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporation under vacuum to fabricate chemical ion-selective field effect transistor (ISFET) microsensors. A high-performance liquid-phase chromatography (HPLC) method was used to verify the non-degradation of the calixarene layers, after the evaporation process. The sensing properties of these ionophores towards alkaline and heavy metal ions were tested. Both devices
Sensors and Actuators B: Chemical, 2007
ABSTRACT Thin films of two partially benzylated β-CDs (β-cyclodextrins) were used to functionaliz... more ABSTRACT Thin films of two partially benzylated β-CDs (β-cyclodextrins) were used to functionalize ITO (indium tin oxide) and Si/SiO2 substrates which were deposited by spin coating technique, to fabricate respectively a diode device and an EIS (electrolyte–insulator–semiconductor) sensor. We have studied electrical properties of ITO/β-CDs (Bz)n=5,10/Al diodes by means of current–voltage measurement and impedance spectroscopy. The application of these new modified β-CD (Bz)n=5,10 in the field of chemical sensors has been studied. Electrochemical capacitance measurements with EIS structures were made to test and calibrate physico-chemical sensors with regards to their sensitivity and selectivity. The sensing properties of these partial benzylated β-CD films towards Pb2+ in aqueous solution for sensor application were tested.A significant effect of the average of benzylation degree on both electrical and sensing properties has been investigated.
Sensors and Actuators A: Physical, 1999
The large interfacial area of the porous silicon is used as ion sensitive membrane support. The p... more The large interfacial area of the porous silicon is used as ion sensitive membrane support. The porous layer is oxidized by Rapid Thermal Oxidation (RTO) technique and a calix(4)arene layer was evaporated under vacuum. The structure is then used as the working electrode of an electrochemical cell and sensor properties were investigated by capacitance measurements. We observed an over-Nernstian response
Sensor Letters, 2009
... R. Mlika1∗, H. Yousfi2, B. Bouchikhi2, I. Dumazet-Bonnamour3, N. Jaffrezic-Renault4∗, and H. ... more ... R. Mlika1∗, H. Yousfi2, B. Bouchikhi2, I. Dumazet-Bonnamour3, N. Jaffrezic-Renault4∗, and H. Ben Ouada1 ... In this objective, a large variety of receptors and transducers were used for sensors applications.14 During the last decades, the use of calixarenes as sen-sitive part of ...
Mechanisms of Development, 1998
XLPOU91, a POU-homeobox gene is expressed in a narrow window during early Xenopus development. We... more XLPOU91, a POU-homeobox gene is expressed in a narrow window during early Xenopus development. We show that ectopic expression of XLPOU91 RNA causes severe posterior truncations in embryos without inhibiting the formation of Spemann's organizer. Ectopic XLPOU91 expression also inhibits mesoderm induction by fibroblast growth factor (FGF) and activin in animal cap explants. Using antisense RNA, we depleted endogenous XLPOU91 protein in animal caps. Gastrula-stage animal caps expressing XLPOU91 antisense RNA do not lose competence to FGF, unlike controls, these animal caps express XBra after FGF treatment. Endogenous XLPOU91 levels are peaking when FGF mesoderm-inducing competence is lost in animal caps. Thus XLPOU91 protein may act as a competence switch during early development, as XLPOU91 levels increase in the embryo, the mesoderm response to FGF is lost.