References of "Malherbe, Cédric"
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See detailBio-chemical Raman imaging using targeted-SERS
Verdin, Alexandre ULiege; Malherbe, Cédric ULiege; Eppe, Gauthier ULiege et al

Poster (2017, September)

Raman and SERS spectral imaging, which consists in reconstructing a Raman intensity profile over a 2D or 3D section of a given sample (in presence or not of a nanosubstrate), allow to visualise the ... [more ▼]

Raman and SERS spectral imaging, which consists in reconstructing a Raman intensity profile over a 2D or 3D section of a given sample (in presence or not of a nanosubstrate), allow to visualise the variation of the chemical composition associated with the micro-structure of the sample. In particular, targeted-SERS imaging also enables the specific imaging of various macromolecules targeted by SERS probes in complex biological samples such as cancerous cells. To illustrate the versatility of Raman imaging, we describe two applications that were investigated recently in our laboratory. First, 3D Raman imaging was used to investigate a microcavity in a matrix of gypsum, revealing fossilised carbonaceous compounds dispersed in a filamentous shape, highly suggesting the presence of fossilised bacteria. Secondly, SERS probes were synthesised to specifically target the FRα receptor of folic acid which are often over-expressed at the surface of cancerous cells. Confocal Raman imaging was used to study the localization of the probes after incubation with KB cells (oral cancer) to confirm the specific targeting of FRα membrane receptors (Fig. 1). Moreover, our SERS probes allowed us to distinguish two different cancerous cell lines (namely KB and PC-3), based on the degree of expression of the FRα receptor of these two lines (high for KB and low for PC-3). In the future, these SERS probes may be used for distinguishing between cancerous and healthy cells since healthy cells have a lower degree of expression of FRα. [less ▲]

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See detailSpray-drying as a tool to disperse conductive carbon inside Na2FePO4F particles by addition of carbon black or carbon nanotubes to the precursor solution
Mahmoud, Abdelfattah ULiege; Caes, Sebastien; Brisbois, Magali et al

in Journal of Solid State Electrochemistry (2017)

In this work, Na2FePO4F-carbon composite powders were prepared by spray-drying a solution of inorganic precursors with 10 and 20 wt% added carbon black (CB) or carbon nanotubes (CNTs). In order to compare ... [more ▼]

In this work, Na2FePO4F-carbon composite powders were prepared by spray-drying a solution of inorganic precursors with 10 and 20 wt% added carbon black (CB) or carbon nanotubes (CNTs). In order to compare the effect of CB and CNTwhen added to the precursor solutions, the structural, electrochemical, and morphological properties of the synthesized Na2FePO4F-xCB and Na2FePO4F-xCNT samples were systematically investigated. In both cases, X-ray diffraction shows that calcination at 600 °C in argon leads to the formation of Na2FePO4F as the major inorganic phase. 57Fe Mössbauer spectroscopy was used as complementary technique to probe the oxidation states, local environment, and identify the composition of the iron-containing phases. The electrochemical performance is markedly better in the case of Na2FePO4F-CNT (20 wt%), with specific capacities of about 100 mAh/g (Na2FePO4F-CNT) at C/4 rate vs. 50 mAh/g for Na2FePO4F-CB (20 wt%). SEM characterization of Na2FePO4F-CB particles revealed different particle morphologies for the Na2FePO4F-CNT and Na2FePO4F-CB powders. The carbon-poor surface observed for Na2FePO4FCB could be due to a slow diffusion of carbon in the droplets during drying. On the contrary, Na2FePO4F-CNT shows a better CNT dispersion inside and at the surface of the NFPF particles that improves the electrochemical performance. [less ▲]

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See detailAccurate Differentiation of Carotenoid Pigments Using Flight Representative Raman Spectrometers
Malherbe, Cédric ULiege; Hutchinson, I. B.; McHugh, M. et al

in Astrobiology (2017), 17(4), 351-362

Raman spectrometers will be utilized on two Mars rover missions, ExoMars and Mars 2020, in the near future, to search for evidence of life and habitable geological niches on Mars. Carotenoid pigments are ... [more ▼]

Raman spectrometers will be utilized on two Mars rover missions, ExoMars and Mars 2020, in the near future, to search for evidence of life and habitable geological niches on Mars. Carotenoid pigments are recognized target biomarkers, and as they are highly active in Raman spectroscopy, they can be readily used to characterize the capabilities of space representative instrumentation. As part of the preparatory work being performed for the ExoMars mission, a gypsum crust colonized by microorganisms was interrogated with commercial portable Raman instruments and a flight representative Raman laser spectrometer. Four separate layers, each exhibiting different coloration resulting from specific halophilic microorganism activities within the gypsum crust, were studied by using two excitation wavelengths: 532 and 785 nm. Raman or fluorescence data were readily obtained during the present study. Gypsum, the main constituent of the crust, was detected with both excitation wavelengths, while the resonance Raman signal associated with carotenoid pigments was only detected with a 532 nm excitation wavelength. The fluorescence originating from bacteriochlorophyll a was found to overwhelm the Raman signal for the layer colonized by sulfur bacteria when interrogated with a 785 nm excitation wavelength. Finally, it was demonstrated that portable instruments and the prototype were capable of detecting a statistically significant difference in band positions of carotenoid signals between the sample layers. [less ▲]

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See detailOn the Habitability of Desert Varnish: a Combined Study by Micro-Raman Spectroscopy, X-Ray Diffraction and Methylated Pyrolysis-Gas Chromatography-Mass Spectrometry
Malherbe, Cédric ULiege; Hutchinson, Ian; Ingley, Richard et al

in Astrobiology (2017)

In 2020, the ESA ExoMars and NASA Mars 2020 missions will be launched to Mars, searching for evidence of past and present life. In preparation for these missions, terrestrial analogue samples of rock ... [more ▼]

In 2020, the ESA ExoMars and NASA Mars 2020 missions will be launched to Mars, searching for evidence of past and present life. In preparation for these missions, terrestrial analogue samples of rock formations on Mars are studied in detail in order to optimize the scientific information that the analytical instrumentation will return. Desert varnishes are thin mineral coatings found on rocks in arid and semi-arid environments on Earth that are recognized as analogue samples. During the formation of desert varnishes (which takes many hundreds of years) organic matter is incorporated and microorganisms may also play an active role in the formation process. During this study, four complementary analytical techniques proposed for Mars missions (X-rays diffraction, Raman spectroscopy, elemental analysis and pyrolysis-gas chromatography-mass spectrometry) were used to interrogate samples of desert varnish and to describe their capacity to sustain life under extreme scenario. For the first time, both the geochemistry and the organic compounds associated with desert varnish are described using an identical set of samples. XRD and Raman spectroscopy measurements were used to non-destructively interrogate the mineralogy of the samples. In addition, the use of Raman spectroscopy instruments enabled the detection of β-carotene, a highly Raman active biomarker. The content and the nature of the organic material in the samples was further investigated using elemental analysis and methylated Py-GC-MS and a bacterial origin was determined to be likely. In the context of planetary exploration, we describe the habitable nature of desert varnish based on the bio-geochemical composition of the samples. Possible interference of the geological substrate on the detectability of pyrolysis products is also suggested. [less ▲]

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See detailIntegrated microfluidic device for the synthesis of SERS substrates
Emonds-Alt, Gauthier ULiege; Malherbe, Cédric ULiege; Monbaliu, Jean-Christophe ULiege et al

Poster (2016, December 19)

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman ... [more ▼]

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman spectroscopy (SERS). This work is divided into 4 axes : (a) bimetallic nanoparticles synthesis in a microreactor, (b) nanoparticles functionnalisation, (c) SERS quantification of glyphosate/AMPA and (d) miniature prototype development composed of axes a to c. The first section aims at the synthesis of bimetallic nanoparticles (Au-Ag, Au-Cu and Ag-Cu) in a microfluidic device. This microfluidic device integrates a first section for the synthesis of monometallic nanoparticles (core) and a second section for the reductive deposition of a second metal (shell). The second axe of this work deals with the functionnalisation of nanoparticles to improve the selectivity of this method for the selected analytes. Two types of functionnalisation are studied : PEGylation (a) with multi-arm PEG ending with -SH and/or (b) with linear heterobifunctionnal PEG. The third axe consists in measuring quantitatively glyphosate and AMPA in different matrices, such as water, urine and fruit juice. Finally, the forth axe deals with the development of a portable detection system to perform on-site analysis. This prototype integrates the microfluidic device for nanoparticles synthesis, their functionnalisation, an injection port followed by a mixing section for the sample and an integrated Raman spectrometer for in-line analysis. [less ▲]

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See detailRaman imaging for diagnostic application
Malherbe, Cédric ULiege; Gilbert, Bernard ULiege; Eppe, Gauthier ULiege

Poster (2016, December 19)

Specific dynamic biochemical compositions and molecular structures characterise healthy cells and tissues. This also stands for pathologies or cellular abnormalities which are accompanied by biochemical ... [more ▼]

Specific dynamic biochemical compositions and molecular structures characterise healthy cells and tissues. This also stands for pathologies or cellular abnormalities which are accompanied by biochemical and molecular changes. Raman spectroscopy can provide unique inputs to correlate the molecular composition and its variations with the diagnosis. In addition, the presence of metal nanoparticles in the molecule vicinity induces a remarkable enhancement (up to 1000000 times) of the Raman signal of small molecules (known as SERS effect). It opens towards applications in the field of trace analysis. In preparation for clinical applications, we evaluate, by Raman mapping, the signal detected from a SERS target deposited on solid state support. [less ▲]

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See detailSpectroscopie Raman: Application à l'Etude de Minéraux
Malherbe, Cédric ULiege; Eppe, Gauthier ULiege

Conference given outside the academic context (2016)

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See detailPreparations for ExoMars: Learning Lessons from Curiosity
Edwards, P.; Hutchinson, I. B.; Morgan, S. et al

Poster (2016, October 16)

In 2020, the European Space Agency will launch its first Mars rover mission, ExoMars. The rover will use a drill to obtain samples from up to 2m below the Martian surface that will then be analysed using ... [more ▼]

In 2020, the European Space Agency will launch its first Mars rover mission, ExoMars. The rover will use a drill to obtain samples from up to 2m below the Martian surface that will then be analysed using a variety of analytical instruments, including the Raman Laser Spectrometer (RLS), which will be the first Raman spectrometer to be used on a planetary mission.To prepare for ExoMars RLS operations, we report on a series of experiments that have been performed in order to investigate the response of a representative Raman instrument to a number of analogue samples (selected based on the types of material known to be important, following investigations performed by NASA's Mars Science Laboratory, MSL, on the Curiosity rover). Raman spectroscopy will provide molecular and mineralogical information about the samples obtained from the drill cores on ExoMars. MSL acquires similar information using the CheMin XRD instrument which analyses samples acquired from drill holes several centimetres deep. Like Raman spectroscopy, XRD also provides information on the mineralogical makeup of the analysed samples.The samples in our study were selected based on CheMin data obtained from drill sites at Yellowknife Bay, one of the first locations visited by Curiosity (supplemented with additional fine scale elemental information obtained with the ChemCam LIBS laser instrument). Once selected (or produced), the samples were characterised using standard laboratory XRD and XRF instruments (in order to compare with the data obtained by CheMin) and a standard, laboratory based LIBS system (in order to compare with the ChemCam data). This characterisation provides confirmation that the analogue samples are representative of the materials likely to be encountered on Mars by the ExoMars rover.A representative, miniaturised Raman spectrometer was used to analyse the samples, using acquisition strategies and operating modes similar to those expected for the ExoMars instrument. The type of minerals detected are identified and compared to the information typically acquired using other analytical science techniques investigating in order to highlight the benefits and drawbacks of using Raman spectroscopy for planetary science applications. [less ▲]

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See detailIntegrated microfluidic device for in line SERS detection for glyphosate and related metabolites
Emonds-Alt, Gauthier ULiege; Malherbe, Cédric ULiege; Monbaliu, Jean-Christophe ULiege et al

Poster (2016, July 07)

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman ... [more ▼]

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman spectroscopy (SERS). This work is divided into 4 axes : (a) bimetallic nanoparticles synthesis in a microreactor, (b) nanoparticles functionnalisation, (c) SERS quantification of glyphosate/AMPA and (d) miniature prototype development composed of axes a to c. The first section aims at the synthesis of bimetallic nanoparticles (Au-Ag, Au-Cu and Ag-Cu) in a microfluidic device. This microfluidic device integrates a first section for the synthesis of monometallic nanoparticles (core) and a second section for the reductive deposition of a second metal (shell). The second axe of this work deals with the functionnalisation of nanoparticles to improve the selectivity of this method for the selected analytes. Two types of functionnalisation are studied : PEGylation (a) with multi-arm PEG ending with -SH and/or (b) with linear heterobifunctionnal PEG. The third axe consists in measuring quantitatively glyphosate and AMPA in different matrices, such as water, urine and fruit juice. Finally, the forth axe deals with the development of a portable detection system to perform on-site analysis. This prototype integrates the microfluidic device for nanoparticles synthesis, their functionnalisation, an injection port followed by a mixing section for the sample and an integrated Raman spectrometer for in-line analysis. [less ▲]

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See detailIntegrated microfluidic device for gold nanoparticles synthesis
Emonds-Alt, Gauthier ULiege; Malherbe, Cédric ULiege; Monbaliu, Jean-Christophe ULiege et al

Poster (2016, May 31)

In order to perform the analysis of organic pollutant in trace by Raman spectroscopy, it is necessary to develop SERS substrates, such as noble metal nanoparticles (NPs). The synthesis of gold or silver ... [more ▼]

In order to perform the analysis of organic pollutant in trace by Raman spectroscopy, it is necessary to develop SERS substrates, such as noble metal nanoparticles (NPs). The synthesis of gold or silver NPs is used for analytical applications. It is therefore important to precisely control the synthesis of these SERS substrates to achieve reproducible measurements. Microfluidics is a very attractive technology for the control of the synthesis parameters such as temperature, reaction time and mixing conditions which affect both the size and the morphology of NPs. The synthesis of gold or silver NPs in microreactor is a technique we are already developing in the laboratory. We develop a method for the continuous synthesis of gold and silver NPs in a segmented regime capillary microreactor. The residence time and temperature have a significant effect on the size of the NPs, enabling to prepare different sizes of NPs using the same microreactor and the same precursor solutions. [less ▲]

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See detailMission ExoMars: Un regard vers l'avenir et le passé
Malherbe, Cédric ULiege; Hutchinson, Ian; Ingley, Richard

Article for general public (2015)

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See detailMiniaturized Raman Spectrometers for Space Applications: the Detectability of Biomarkers in Geological Matrices Relevant to Mars Exploration
Malherbe, Cédric ULiege; McHugh, Melissa; Hutchinson, Ian B. et al

Conference (2015)

A Raman spectrometer will be utilized on a planetary exploration mission for the first time when the ExoMars rover is launched in 2018. A Raman spectroscopy instrument was selected for inclusion on the ... [more ▼]

A Raman spectrometer will be utilized on a planetary exploration mission for the first time when the ExoMars rover is launched in 2018. A Raman spectroscopy instrument was selected for inclusion on the ExoMars mission because of its ability to assess the habitability and to search for evidence of life on Mars. Indeed Raman spectrometers have the capability to detect geological substances which are inorganic molecules and inorganic molecular ions constituting the rocky surface of Mars. Information on the nature of rocks present on the surface of Mars will provide information about the habitability of the planet. Besides the detection of geomarkers, Raman spectrometers have the ability to detecting potential biological-derivative substances, often referred to as biomarkers. These biomarkers are organic molecules originating from extent or extinct living organisms. In preparation for ExoMars, it is crucial to study the detection capability of miniaturized Raman spectrometers (specifically developed for space missions and therefore compromised by the associated challenging constraints such as minimal power budget, mass budget, data budget and overall envelope) on both lab synthetic samples and natural terrestrial analogues samples. We present here a systematic comparison of the capability of a number of Raman spectrometer designs/configurations to detect biomarkers in geological matrices that are relevant to the Martian surface and subsurface. In particular, we will compare spectral images recorded with benchtop instruments and a Raman Laser Spectrometer prototype developed at the University of Leicester to optimize/characterize the camera system that will be used for the ExoMars mission. Several parameters such as the excitation wavelength, the number of spectra recorded per sample and selection of optimal operating modes will be discussed. As an example, the habitability of desert varnish in the context of planetary exploration will be discussed in detail. Desert varnish are mineral coatings comprising clay, iron oxide and manganese oxide which are associated with living organisms in many stable extreme environment on Earth. Desert varnish are recognized as terrestrial analogue samples for martian surface because similar mineral formation have been recently identified on Mars. [less ▲]

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See detailBiogeological Analysis of Desert Varnish Using Portable Raman Spectrometers
Malherbe, Cédric ULiege; Ingley, Richard; Hutchinson, Ian et al

in Astrobiology (2015)

Desert varnishes are thin, dark mineral coatings found on some rocks in arid or semi-arid environments on Earth. Microorganisms may play an active role in their formation, which takes many hundreds of ... [more ▼]

Desert varnishes are thin, dark mineral coatings found on some rocks in arid or semi-arid environments on Earth. Microorganisms may play an active role in their formation, which takes many hundreds of years. Their mineral matrix may facilitate the preservation of organic matter and is therefore of great relevance to martian exploration. Miniaturized Raman spectrometers (which allow nondestructive analysis of the molecular composition of a specimen) will equip rovers in forthcoming planetary exploration missions. In that context, and for the first time, portable Raman spectrometers operating in the green visible (532 nm as currently baselined for flight) and in the near-infrared (785 nm) were used in this study to investigate the composition (and substrate) of several samples of desert varnish. Rock samples that were suspected (and later confirmed) to be coated with desert varnish were recovered from two sites in the Mojave Desert, USA. The portable spectrometers were operated in flight-representative acquisition modes to identify the key molecular components of the varnish. The results demonstrate that the coatings typically comprise silicate minerals such as quartz, plagioclase feldspars, clays, ferric oxides, and hydroxides and that successful characterization of the samples can be achieved by using flightlike portable spectrometers for both the 532 and 785 nm excitation sources. In the context of searching for spectral signatures and identifying molecules that indicate the presence of extant and/or extinct life, we also report the detection of β-carotene in some of the samples. Analysis complications caused by the presence of rare earth element photoluminescence (which overlaps with and overwhelms the organic Raman signal when a 785 nm laser is employed) are also discussed. Key Words: Desert varnish-Raman spectroscopy-ExoMars-Portable spectrometers-Planetary science. [less ▲]

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See detailAvoiding misidentification of bands in planetary Raman spectra
Harris, Liam; McHugh, Melissa; Hutchinson, Ian B. et al

in Journal of Raman Spectroscopy (2015)

Raman spectroscopy has been identified as a powerful tool for astrobiology and remote robotic planetary exploration. It can be used to identify and characterise rock matrices, mineral inclusions and ... [more ▼]

Raman spectroscopy has been identified as a powerful tool for astrobiology and remote robotic planetary exploration. It can be used to identify and characterise rock matrices, mineral inclusions and organic molecules and is demonstrablyeffective at identifying biomarkers, or indicators of biological activity. The ExoMars rover, jointly operated by the European and Russian Federal Space Agencies, will carry the first Raman spectrometer into space when it launches in 2018 and two further Raman instruments have recently been announced as part of the payload onboard the National Aeronautics and Space Administration’s Mars 2020 rover. Each of these spectrometers however will, by necessity, have poorer resolution than the most sophisticated laboratory instruments because of mass, volume and power constraints and the space readiness of the requisite technologies. As a result, it is important to understand the minimum instrument specification requiredto achieve the scientific objectives of a mission, in terms of parameters such as spectral resolution and laser footprint size. This requires knowledge of the target minerals and molecules between which there may be ambiguity when identifying bands in spectra from geological samples. Here, we present spectra from a number of Mars analogue samples that include a range of such molecules, highlighting where such confusion may occur and identifying the most useful bands for differentiation. It is recommended that a Ramanspectrometer achieves a resolution of at least 3 cm-1 and covers a spectral range from 100 to 4000 cm-1 in order to differentiate between all of the target molecules presented here. [less ▲]

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See detailA facile and fast electrochemical route to produce functional few-layer graphene sheets for lithium battery anode application
Ouhib, Farid ULiege; Aqil, Abdelhafid ULiege; Thomassin, Jean-Michel ULiege et al

in Journal of Materials Chemistry A (2014), 2(37), 15298-15302

A simple approach for the production of polymer functionalized graphene nanosheets is reported. The resulting polyacrylonitrile chemisorbed on graphene sheets is made of 1 to 2 layers, with a large ... [more ▼]

A simple approach for the production of polymer functionalized graphene nanosheets is reported. The resulting polyacrylonitrile chemisorbed on graphene sheets is made of 1 to 2 layers, with a large majority of graphene single-layers. This novel functionalized graphene exhibits good cycling stability as an anode in Li-ion batteries without a conductive additive or binder. [less ▲]

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See detailPreparations for the use of Raman spectrometers on Mars
Malherbe, Cédric ULiege; Ingley, Richard; Hutchinson, Ian B. et al

Conference (2014, October)

Raman spectroscopy has been selected as a non-destructive powerful analytical method for forthcoming planetary exploration. In the context of the upcoming ExoMars and NASA 2020 missions (developed by the ... [more ▼]

Raman spectroscopy has been selected as a non-destructive powerful analytical method for forthcoming planetary exploration. In the context of the upcoming ExoMars and NASA 2020 missions (developed by the European Space Agency, IKI Roscomos and NASA) analysis of the biological and geological terrestrial analogues using laboratory instrumentation is of great importance; especially testing the performance of flight-like operating modes and conditions on the feasibility of flight instruments meeting their science goals. Here we present a set of measurements of terrestrial analogues (among them desert varnishes) selected in preparation for in-situ Raman analysis on Mars. Laboratory instrumentation has been used to fully characterise the samples in addition to being operated in modes consistent with ExoMars RLS instrument flight designs, sample preparation and delivery. We discuss the performance of the spectrometers regarding the detection of the target signatures and their geological context. The impact of instrument operating modes and application of flight instrument sampling philosophy (i.e. spot size, grain size, number of target locations, sample preparation and delivery) on the signal intensity and the limits of detection are also discussed. [less ▲]

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