Rabah Mouras

Rabah Mouras
University of Limerick | UL · Department of chemical siences

PhD

About

60
Publications
6,330
Reads
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912
Citations
Additional affiliations
June 2014 - present
University of Limerick
Position
  • Reseacrh Fellow
April 2013 - May 2014
The University of Edinburgh
Position
  • Research fellow and Research Manager
January 2008 - present
The University of Edinburgh
Position
  • Research Associate
Description
  • CARS microscopy, AFM, TERS drug delivery, stem cells
Education
June 2005
London Chamber of Commerce and Industry and CUCES, Nancy
Field of study
  • English for Business (2 Months training)
December 1997 - March 2002
November 1996 - October 1997

Publications

Publications (60)
Article
Full-text available
Indiscriminate and sporadic use of antibiotics has contributed to the emergence of drug resistance phenomenon in bacteria including but not limited to Staphylococcus aureus. These drug-resistant bacteria have been threatening safety in hospitals and adversely affecting human health. Here we report a strategy to design photo-stimulated theranostic n...
Article
Full-text available
The present study was aimed to convert CO2 into methanol which not only addresses the potential solution for controlling the CO2 concentration level in the atmosphere but also offers an alternative approach for the production of renewable energy source. In this perspective, a hybrid photocatalyst, [email protected]2O4 was synthesized, characterized...
Article
Calcium carbonate and carbonate-hydroxyapatite are known to form inorganic components of crystals and calcareous concretions found in many non-skeletal tissues and structures including the pineal gland. We used advanced surface analyses techniques such as polarization microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), microfocu...
Article
Noble-metal nanoparticles size and packing density are critical for sensitive surface-enhanced Raman scattering (SERS) and controlled preparation of such films required to achieve reproducibility. Provided that they are made reliable, Ag shell on SiO2 microscopic particles (Ag/SiO2) are promising candidates for lab-on-a-bead analytical measurements...
Article
Full-text available
Fast, label-free optical identification and quantification of biomolecules and other relevant biological materials in microfluidic devices and the vascular system will play a major role in liquid biopsy and related diagnoses. An optical microscope probing simultaneously non-linear coherent anti-Stokes Raman scattering (CARS) and linear scattering (...
Article
Full-text available
Drug delivery monitoring and tracking in the human body are two of the biggest challenges in targeted therapy to be addressed by nanomedicine. The ability of imaging drugs and micro-/nanoengineered drug carriers and of visualizing their interactions at the cellular interface in a label-free manner is crucial in providing the ability of tracking the...
Article
Full-text available
Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapat...
Conference Paper
A bench-top confocal microscope employing a fast mid-infrared laser has been developed and used to monitor in a label-free manner the uptake of biologically-compatible drug polyelectrolyte capsules containing anticancer drug by MCF-7 breast cancer cells.
Article
We have experimentally investigated the enhancement in spatial resolution by image subtraction in mid-infrared central solid-immersion lens (c-SIL) microscopy. The subtraction exploits a first image measured with the c-SIL point-spread function (PSF) realized with a Gaussian beam and a second image measured with the beam optically patterned by a si...
Article
Full-text available
The use of stem cells to support tissue repair is facilitated by loading of the therapeutic cells with magnetic nanoparticles (MNPs) enabling magnetic tracking and targeting. Current methods for magnetizing cells use artificial MNPs and have disadvantages of variable uptake, cellular cytotoxicity and loss of nanoparticles on cell division. Here we...
Article
Full-text available
The spatial resolution in far-field mid-infrared (λ>2.5 μm) microscopy and microspectroscopy remains limited with the full-width at half maximum of the point-spread function ca. λ/1.3; a value that is very poor in comparison to that commonly accessible with visible and near-infrared optics. Hereafter, it is demonstrated however that polymer beads t...
Chapter
This overview seeks to highlight those technologies which are poised at the forefront of functional, chemical and morphological imaging. Both labelled and label-free techniques are considered, with a particular emphasis on label-free, high resolution ambient imaging techniques. The analysis of the IR spectra of materials reveals a tell-tale 'finger...
Article
The aim of treatment in congenital adrenal hyperplasia is to suppress excess adrenal androgens while achieving physiological glucocorticoid replacement. However, current glucocorticoid replacement regimes are inadequate because doses sufficient to suppress excess androgens almost invariably induce adverse metabolic effects. Although both cortisol a...
Article
The uptake of nanomaterials (NMs) by cells is critical in determining their potential biological impact, whether beneficial or detrimental. Thus, investigation of NM internalization by cells is a common consideration in hazard and efficacy studies. There are currently a number of approaches that are routinely used to investigate NM-cell interaction...
Conference Paper
Full-text available
Quantitative recognition based on antibody-antigen specificity is the cornerstone of modern clinical diagnosis. The rapid, unambiguous identification of disease markers in low copy numbers is essential for early detection and good patient outcome. Vibrational Raman spectroscopy, with its fingerprint specificity and capacity for multiplex detection,...
Article
Full-text available
Recent work indicates that the nuclear envelope is a major signaling node for the cell that can influence tissue differentiation processes. Here we present two nuclear envelope transmembrane proteins TMEM120A and TMEM120B that are paralogs encoded by the Tmem120A and Tmem120B genes. The TMEM120 proteins are expressed preferentially in fat and both...
Article
Full-text available
We have developed a multimodal optical platform for label‐free imaging on the basis of nonlinear optical microscopy (NLO) for applications in biology and biomedical science. Three application areas have been chosen as examples: regenerative medicine, drug delivery monitoring and cancer diagnosis. Obtained data showed the potential of NLO microscopy...
Article
Full-text available
Adult stem cells (SCs) hold great potential as likely candidates for disease therapy but also as sources of differentiated human cells in vitro models of disease. In both cases, the label-free assessment of SC differentiation state is highly desirable, either as a quality-control technology ensuring cells to be used clinically are of the desired li...
Article
The characterisation of stem cells is of vital importance to regenerative medicine. Failure to separate out all stem cells from differentiated cells before therapies can result in teratomas - tumours of multiple cell types. Typically, characterisation is performed in a destructive manner with fluorescent assays. A truly non-invasive method of chara...
Article
Full-text available
Adipose-derived stem cells (ADSCs) are adult stem cells isolated from lipoaspirates. They are a good candidate for autologuous cell therapy and tissue engineering. For these applications, label-free imaging could be critical to assess noninvasively the efficiency of stem cell (SC) differentiation. We report on the development and application of a m...
Conference Paper
Full-text available
We have used a versatile and powerful microscope[1] for multi-modal biomedical imaging on which we combine Coherent Anti-Stokes Raman Scattering (CARS) with Two Photon Excitation Fluorescence (TPEF) using a Nd: YVO4 pump laser. We acquired 2PEF, CARS, and phase contrast images of Multilamellar Vesicles (MLVs) and Giant Unilamellar Vesicles (GUVs),...
Article
Polyethylene has been used as a bearing surface in numerous applications for in excess of four decades. The semi-crystalline structure of this material has been proposed to have fundamental influence over its wear characteristics; however, reports considering its crystalline phase are sparse. Nanotribological measurements on supported polyethylene...
Article
In-depth micro-Raman profiling of He+-implanted LiNbO 3 has been performed. It is demonstrated that in the buried nuclear stopping layer a transition from point to extended defects occurs at threshold dose in the range 1 − 2 × 10 15 ions/cm 2 related to polarization nano-clusters formation.
Article
Full-text available
Lithium niobate thin films were deposited on sapphire substrate by radio-frequency magnetron sputtering technique. One and two dimensional structures have been made using a KrF excimer laser at 248 nm and 6 ns pulse width, under various conditions of ablation, in order to assess the applicability of laser direct-writing of photonic waveguides. The...
Article
Full-text available
A multimodal nonlinear optical microscope that combines coherent anti-Stokes Raman scattering (CARS), two-photon excitation fluorescence (TPEF), second-harmonic generation (SHG) and sum-frequency generation (SFG) was developed and applied to image breast cancer tissue and MCF-7 cells as well as monitoring anticancer drug delivery in live cells. TPE...
Article
Full-text available
There is a requirement for a noninvasive technique to monitor stem cell differentiation. Several candidates based on optical spectroscopy are discussed in this review: Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and coherent anti-Stokes Raman scattering (CARS) microscopy. These techniques are briefly described, and the abili...
Chapter
We report on the construction of a highly flexible system for advanced biological imaging, where all the following imaging techniques are integrated into the same microscope: Coherent anti-Stokes Raman scattering (CARS), two photon excitation fluorescence (TPEF), second harmonic generation (SGH), sum frequency generation (SFG), fluorescence lifetim...
Article
We discuss the range of tip-enhanced optical microscopies - namely mapping scattered light, fluorescence, Raman and coherent anti-Stokes Raman scattering (CARS) signals on the scale of 10-20 nm. Through the use of measurements and finite-element simulations, we explain what the optimum tip materials and sizes are and illumination wavelengths to use...
Article
Tip-enhanced optical spectroscopy is an approach that holds a good deal of promise for the nanoscale characterisation of matter. Tip-enhanced Raman spectroscopy (TERS) has been demonstrated on a variety of samples: inorganic, organic and biological. Imaging using TERS has been shown for carbon nanotubes due to their high scattering efficiency. Ther...
Article
We have constructed a novel, versatile Coherent anti-Stokes Raman scattering (CARS) microscope for biological imaging. The system employs a Nd:YVO4 laser as Stokes (6 ps, 1064 nm), and a tunable optical parametric oscillators (OPOs) (5 ps, 700–1000 nm) as pump excitation, resulting in an observable range of ∼600–4000 cm−1. A second OPO can be used...
Article
In this work, we report on the fabrication and characterization of surface microstructures in lithium niobate thin films and single crystal by using KrF excimer laser ablation technique at 248 nm with 6 ns pulse width. Ablation is carried out through a mask projection set-up. Various experimental conditions are used in order to evaluate the potenti...
Article
It has been established by Raman scattering study that the optical damage in nominally pure LiNbO3 crystals presents an irreversible part. This irreversible fraction of the optical damage is induced only by the high-intensity (I⩾25kW/cm2) exposition for a long time, and it has accumulative character with exposure time. This irreversible effect has...
Article
Full-text available
We present and discuss the mechanism of incorporation of Mg ions in congruent lithium niobate where we assume the coexistence of both lithium and niobium vacancies induced for charge compensation. This model is supported by the site spectroscopy afforded by Raman scattering data. The dependence of the concentration of various intrinsic defects, der...
Article
Laser photoinduced properties in iron-doped LiNbO3 crystals were investigated by means of Raman spectroscopy. The results were compared with data recorded in undoped crystals. The appearance of several lines unexpected by the Raman selection rules were interpreted by means of a nonlinear polarization caused by the photovoltaic effect. This polariza...
Article
Micro-Raman scattering are used like a probe to determiner the Co substitution process in the system Li{2}O-Ta{2}O{5}-(CoO){2} . We follow the Raman spectra modifications as function of the substitution rate along the line B: Li{1+x}Ta{1-x/2}Co{3x/4}O{3} and confirm the substitution of Co2+ ions on the Li+ site.
Article
We demonstrate that the Raman spectroscopy method may be effectively used for accurate determination of optical damage profiles in LiNbO3-based elements used in the various devices utilizing high-power laser beams. It has been established, that there is an irreversible fraction of the optical damage induced only by the high-intensity (≥25 kW/cm2) i...
Article
The growth of CdS nanocrystals (NCs) embedded in bulk KCl single crystal matrix is performed using the Czochralski method. The X-ray diffraction reveals the incorporation of the CdS NCs with a cubic structure inside the KCl matrix. The optical density measurements of the CdS NCs embedded in KCl single crystal show a shift of the absorption edge tow...
Article
The elaboration of the CdS nanocrystals embedded in a NaCl single crystal has been performed using the Czochralski method. The optical density spectrum shows a blue shift of the absorption edge towards the high energies. The energy gap has been found to be 2.70eV. The photoluminescence has been assigned to the neutral-donor band (D0, X) and radiati...
Article
The ZnO nanocrystals (NCs) embedded in KBr single crystal matrix has been fabricated using the Czochralski (Cz) method. X-ray diffraction has confirmed the embedding of ZnO nanocrystals inside the bulk KBr matrix. A blue shift of the absorption edge of the obtained samples has been observed. Moreover, ZnO nanocrystals embedded in bulk KBr single cr...
Thesis
Le niobate de lithium est un cristal largement employé en optique intégré et en optoélectronique pour réaliser des guides d'ondes, des modulateurs...en raison de ses coefficients électro-optiques et optiques non linéaires élevés. L'amélioration des performances des cristaux de LiNbO3 par le contrôle de la str?chiométrie ou par un dopage approprié,...
Article
Raman scattering in nominally pure lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) crystals has been studied at high-intensity excitation. Significant photoinduced perturbations of Raman spectra of congruently melting LiNbO3 are discovered in contrast to Raman scattering observed in both nearly stoichiometric LiNbO3 and congruently melting...
Article
The LiNbO3 crystals doped with Nd3+, Dy3+ and Er3+ ions were investigated by means of Raman scattering measurements. Data were compared with results recorded in undoped congruent crystal and highly Mg-doped samples. The doping dependence of frequency and damping in the E(TO1) and the two lowest frequency A1(TO) phonon modes were employed to deduce...
Article
Photo-induced birefringence changes are investigated on several undoped LiNbO3 crystals as a function of laser-irradiation time and intensity. Comparison points out that the changes are the smallest in the crystals grown from high temperature top seeded solution (TSS). It is concluded that the optical damage resistance in undoped LiNbO3 crystals is...
Article
Full-text available
The defect structure of Mg-doped lithium niobate crystals was studied with varying Mg doping concentration by means of Raman scattering measurements. The Mg content dependences of both the frequency and damping of the two lowest-frequency A1(TO) phonon modes were used to derive the Mg incorporation mechanism in the LiNbO3 lattice. Results indicated...
Article
Full-text available
We study the concentration dependence of Raman spectra of MgO doped LiNbO3 crystals. We focus our attention on the width of the E(TO1) phonon located at 153 cm-1, which is used in pure lithium niobate to determine precisely the composition of the crystal. The concentration dependence of this peak differes with the nature of doping. The results supp...