0000000000013501
AUTHOR
Céline Elie-caille
Formation Kinetics of Mixed Self-Assembled Monolayers of Alkanethiols on GaAs(100)
International audience; We report on the formation kinetics of mixed self-assembled monolayers (SAMs) comprising 16-mercaptohexadecanoic acid (MHDA) and 11-mercapto-1-undecanol (MUDO) thiols on GaAs(100) substrates. These compounds were selected for their potential in constructing highly selective and efficient architectures for biosensing applications. The molecular composition and quality of one-compound and mixed SAMs were determined by the Fourier transform infrared absorption spectroscopy measurements. The formation of enhanced-quality mixed SAMs was investigated as a function of the molecular composition of the thiol mixture and the proportion of ethanol/water solvent used during thei…
ERa dimerization: a key factor for the weak estrogenic activity of an ERa modulator unable to compete with estradiol in binding assays
PMID: 27400858; International audience; AbstractEstrothiazine (ESTZ) is a weak estrogen sharing structural similarities with coumestrol. ESTZ failed to compete with [3H]17β-estradiol ([3H]17β-E2) for binding to the estrogen receptor α (ERα), questioning its ability to interact with the receptor. However, detection by atomic force spectroscopy (AFS) of an ESTZ-induced ERα dimerization has eliminated any remaining doubts. The effect of the compound on the proliferation of ERα-positive and negative breast cancer cells confirmed the requirement of the receptor. The efficiency of ESTZ in MCF-7 cells was weak without any potency to modify the proliferation profile of estradiol and coumestrol. Gro…
Influence of a Thiolate Chemical Layer on GaAs (100) Biofunctionalization: An Original Approach Coupling Atomic Force Microscopy and Mass Spectrometry Methods
International audience; Widely used in microelectronics and optoelectronics; Gallium Arsenide (GaAs) is a III-V crystal with several interesting properties for microsystem and biosensor applications. Among these; its piezoelectric properties and the ability to directly biofunctionalize the bare surface, offer an opportunity to combine a highly sensitive transducer with a specific bio-interface; which are the two essential parts of a biosensor. To optimize the biorecognition part; it is necessary to control protein coverage and the binding affinity of the protein layer on the GaAs surface. In this paper; we investigate the potential of a specific chemical interface composed of thiolate molec…
Reconstitution of a protein monolayer on thiolates functionalized gaas surface
International audience; In the aim to realize an efficient resonant biosensor, gallium arsenide (GaAs) presents many advantages. In addition to its properties of transduction, GaAs is a crystal for which microfabrication processes were developed, conferring the possibility to miniaturize the device and integrate electronic circuit. Moreover, the biofunctionalization could be realized on the crystalline surface without layer deposition, constituting a real advantage to perform reusable sensor. The functionalization of GaAs surface was engaged in order to immobilize a protein monolayer on this substrate. Functionalization was done using a mixed self assembled monolayer of thiolate molecules. …
Regenerable ZnO/GaAs Bulk Acoustic Wave Biosensor for Detection of Escherichia coli in “Complex” Biological Medium
A regenerable bulk acoustic wave (BAW) biosensor is developed for the rapid, label-free and selective detection of Escherichia coli in liquid media. The geometry of the biosensor consists of a GaAs membrane coated with a thin film of piezoelectric ZnO on its top surface. A pair of electrodes deposited on the ZnO film allows the generation of BAWs by lateral field excitation. The back surface of the membrane is functionalized with alkanethiol self-assembled monolayers and antibodies against E. coli. The antibody immobilization was investigated as a function of the concentration of antibody suspensions, their pH and incubation time, designed to optimize the immunocapture of bacteria. The perf…
Specificity and Sensitivity Characterization of a Gallium Arsenide Resonant Bio-Sensor
International audience; The characterization of the performances of a Gallium Arsenide (GaAs) based biosensor, in terms of sensitivity and specificity, is reported. The design of the sensor consists in a resonant membrane fabricated in GaAs crystal that operates at shear modes of bulk acoustic waves generated by lateral field excitation. The transducer element was fabricated by using typical clean room microfabrication techniques. The backside of the membrane is functionalized by a self-assembled monolayer (SAM) of alkanethiols to immobilize bio-receptors, which will allow the specific capture of the analyte of interest. The theoretical sensitivity of the sensor had been determined by model…
Deposition and characterization of ZnO thin films on GaAs and Pt/GaAs substrates
Abstract This work reports the deposition and characterization of piezoelectric ZnO thin films on semi-insulating GaAs substrates for the fabrication of bulk acoustic waves sensors. ZnO films are deposited at 350 °C and low deposition rate using reactive radio frequency magnetron sputtering. The use of a Pt bottom electrode, between ZnO and GaAs, with and without Ti buffer layer, as well as the effect of the substrate crystallographic orientation are investigated. The characterization of the deposited films is performed to determine the optimal parameters for obtaining high-quality films and ZnO residual conductivity. ZnO films are textured along the c-axis for all GaAs cuts. The highest st…
Cell imaging connected with protein mapping to investigate glyphosate induced toxicity on human keratinocytes
During the skin ageing which is accelerated by environmental factors, the generated reactive oxygen species make unstable the "proliferation/differentiation/apoptosis" coupling of epidermal cells. A biochemical study, previously realized on human keratinocyte cultures treated by a pesticide, glyphosate, allowed the validation of an in vitro model of skin ageing. In this work, we propose to study the loss of HaCaT cell integrity appearing after this chemical induced-oxidative stress. An original approach, combining a micro- to nanoscale cell characterization and analysis of fluctuating protein expression, is proposed: a) the exploration of cell growth and morphology through fluorescence and …
Development of extracellular vesicle-based medicinal products: A position paper of the group “Extracellular Vesicle translatiOn to clinicaL perspectiVEs – EVOLVE France”
International audience; Extracellular vesicles (EV) are emergent therapeutic effectors that have reached clinical trial investigation. To translate EV-based therapeutic to clinic, the challenge is to demonstrate quality, safety, and efficacy, as required for any medicinal product. EV research translation into medicinal products is an exciting and challenging perspective. Recent papers, provide important guidance on regulatory aspects of pharmaceutical development, defining EVs for therapeutic applications and critical considerations for the development of potency tests. In addition, the ISEV Task Force on Regulatory Affairs and Clinical Use of EV-based Therapeutics as well as the Exosomes C…