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See detailDevelopment of bimetallic nanoparticles for Surface-Assisted Laser Desorption/Ionisation Mass Spectrometry imaging of small molecules
Verdin, Alexandre ULiege; Malherbe, Cédric ULiege; Bertrand, Virginie ULiege et al

Poster (2019, June 04)

Mass Spectrometry Imaging (MSI) allows the simultaneous visualisation of hundreds to thousands of molecules in biological tissue slides enabling the comprehension of complex biochemical processes ... [more ▼]

Mass Spectrometry Imaging (MSI) allows the simultaneous visualisation of hundreds to thousands of molecules in biological tissue slides enabling the comprehension of complex biochemical processes. Additionally, the analysis of untargeted MSI data with advanced statistical tools has the potential to reveal pertinent features of the sample such as the progression or outcome of a disease or the response to a treatment. Recently, metallic nanoparticles (NPs) have received increasing attention as desorption/ionization substrate for Surface-Assisted Laser Desorption/Ionization-MS (SALDI-MS). Metallic NPs provide several advantages over organic MALDI matrices for the analysis of small molecules: high absorption coefficients of the ionization laser (in the UV-Visible range), the ability to load small molecules on their surface by physical or chemical adsorption, little interferences in the low m/z range and a simple sample preparation (no crystallization required). SALDI-MSI is adapted to study the variations of the molecular composition associated with various diseases and to visualize the localization of pertinent small molecules in complex biological tissues. Innovative Au@Ag (core@shell) bimetallic NPs are interesting for SALDI applications, especially because controlling the thickness of the Ag shell around the Au core allows the tuning of the absorption in near-UV. These Au@Ag NPs permits to maximize the energy absorption for an efficient ionization and desorption of analytes adsorbed to the NPs. Moreover Au@Ag NPs can also be used for Surface-Enhanced Raman Spectroscopy (SERS) imaging which is a highly complementary technique. We report here a study of ovarian cancer tissue using Au@Ag NPs to characterize the overexpression of membrane receptor in the tumor by SERS imaging and to gain molecular insights by SALDI-MSI. [less ▲]

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See detailDevelopment of bimetallic nanoparticles for Surface-Assisted Laser Desorption/Ionisation Mass Spectrometry imaging of small molecules
Verdin, Alexandre ULiege; Malherbe, Cédric ULiege; Bertrand, Virginie ULiege et al

Poster (2019)

Metallic nanoparticles (NPs) receive increasing attention as desorption/ionization substrate for Surface-Assisted Laser Desorption Ionization-MS (SALDI-MS) [1]. Metallic NPs offer high extinction ... [more ▼]

Metallic nanoparticles (NPs) receive increasing attention as desorption/ionization substrate for Surface-Assisted Laser Desorption Ionization-MS (SALDI-MS) [1]. Metallic NPs offer high extinction coefficients of the ionization laser (in the UV-Visible range of wavelengths) and are able to ionize small molecules with little interferences in the low m/z range with a simple sample preparation [2]. SALDI-MSI is adapted to study the variations of the molecular composition associated with various diseases and to visualize the localization of pertinent small molecules in complex biological tissues. Innovative Au@Ag (core@shell) bimetallic NPs are interesting for SALDI applications, especially because controlling the thickness of the Ag shell around the Au core allows the tuning of the absorption in near-UV. The Au@Ag NPs permits to vary the energy transfer for an efficient ionization and desorption of analytes adsorbed to the NPs. Moreover Au@Ag NPs can also also be used for Surface-Enhanced Raman Spectroscopy (SERS) imaging. We report here a study of ovarian cancer tissue using Au@Ag NPs to localize the tumor by SERS imaging and to gain molecular insight of tumors by SALDI-MSI. [less ▲]

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See detailMetallic nanoparticles: an interesting option for mass spectrometry imaging of small molecules in tissues
Verdin, Alexandre ULiege; Müller, Wendy ULiege; Bertrand, Virginie ULiege et al

Poster (2018, July 05)

MALDI mass spectrometry imaging is a central technique for the visualisation and identification of a wide variety of molecules in biological samples, especially in tissues slides. However, organic ... [more ▼]

MALDI mass spectrometry imaging is a central technique for the visualisation and identification of a wide variety of molecules in biological samples, especially in tissues slides. However, organic matrices used for the desorption and ionisation of molecules suffers from major limitations, particularly for the analysis of small molecules due to interferences from the matrix in the low m/z range. In this preliminary study we compared the performances of 9-aminoacridine, a well known organic matrix used for small molecules anaylsis, and metallic nanoparticles to evaluate the information obtained from both method. Ionisation by nanoparticles is known as Surface-Assisted Laser Desorption Ionisation (SALDI). Metallic nanoparticles seem to be a promising substrate for MS analysis of small compounds in tissues and reveals information that are complementary to those obtained by MALDI. [less ▲]

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See detailDevelopment of nanoprobes for cancerous tissues imaging by Surface-Enhanced Raman Spectroscopy
Müller, Wendy ULiege; Verdin, Alexandre ULiege; Malherbe, Cédric ULiege et al

Poster (2018, May 17)

Early detection and precise characterization of cancers is one of the major challenges in medicine. Consequently, there is a strong need to develop highly sensitive, specific and quick analytical ... [more ▼]

Early detection and precise characterization of cancers is one of the major challenges in medicine. Consequently, there is a strong need to develop highly sensitive, specific and quick analytical techniques. Among the emerging methods allowing the analysis of cancerous samples, Surface-Enhanced Raman Spectroscopy (SERS), an amplified technique of vibrational spectroscopy based on Raman scattering, is particularly suitable. The signal enhancement in SERS, up to 10^12-fold in the presence of metallic nanoparticles near the Raman-active molecule, offers a better sensitivity than in “classic” Raman spectroscopy and thus allows the analysis of molecules in weaker concentrations. One of the advantages of the nanoparticles used in SERS is that they can be functionalized in order to specifically target a molecule of interest and therefore give information about the spatial location of biomarkers via SERS imaging. Our research aims at developing SERS nanoprobes functionalized with folic acid, complementary to the FRalpha receptor (folate receptor alpha), a membrane receptor overexpressed in many types of cancers. SERS imaging with these nanoprobes will then enable to spot cancerous areas within human cancerous tissues and to discriminate between healthy and cancerous tissues. The preliminary results of our study show that nanoprobes can bind to tissues and more particularly at the level of membrane structures and that they can be detected via SERS imaging. SERS imaging also allows to observe a signal accumulation in presumed cancerous areas, in correlation with the histological H&E analysis. Finally, SERS imaging of healthy and cancerous tissues seems to indicate higher signal intensity within cancerous tissues than within healthy tissues. [less ▲]

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See detailDevelopment of highly sensitive SERS nanoprobes for cellular imaging of Folate Receptor alpha
Verdin, Alexandre ULiege; Malherbe, Cédric ULiege; Cambroisier, Florie ULiege et al

Poster (2018, March)

During the last decade, spectroscopic cellular imaging has increasingly become a powerful characterization method for the study of all kind of cellular-related disease. In this context, Surface-Enhanced ... [more ▼]

During the last decade, spectroscopic cellular imaging has increasingly become a powerful characterization method for the study of all kind of cellular-related disease. In this context, Surface-Enhanced Raman Spectroscopy (SERS) is a powerful technique with many advantages over other spectroscopic techniques such as fluorescence or infrared spectroscopy. The SERS effect is capable of providing huge enhancement factors, highly increasing the sensitivity of Raman spectroscopy. One interesting approach is to use so called “SERS nanoprobes” to selectively target and detect a particular receptor, protein, DNA sequence, etc. In the area of SERS detection of cancerous cells, the target of these nanoprobes is usually a surface receptor that is characteristic of the cancerous state of the cell, or that is overexpressed in a cancerous cell in comparison to a healthy situation. In this study, we investigated the targeting of the Folate Receptor alpha (FRα) which is overexpressed in several cancers (ovarian and lung adenocarcinoma, among others) and can therefore be used for the imaging and detection of cancerous cells. We focused on the development of highly sensitive SERS nanoprobes, combining bimetallic nanoparticles and resonant Raman-active molecules. We successfully imaged Folate Receptor α at the surface of two kinds of cancerous cells (KB and PC-3) thanks to the high confocality of the Raman micro-spectrometer. Moreover, we were able to distinguish these two kinds of cells by measuring the SERS intensity coming from each cell population, since both kinds of cells have a different expression level of the FRα receptor and will therefore accumulate different amounts of nanoprobes. Our approach provides new perspectives toward the discrimination of cancerous and healthy cells in real samples. [less ▲]

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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 detailRaman imaging for (bio)chemical applications
Malherbe, Cédric ULiege; Verdin, Alexandre ULiege; Gilbert, Bernard et al

Scientific conference (2017, July 06)

Detailed reference viewed: 26 (7 ULiège)
See detailOptimisation de sondes SERS pour des applications bio-analytiques
Verdin, Alexandre ULiege

Master's dissertation (2017)

La spectroscopie Raman exaltée de surface (SERS) est une technique permettant des analyses rapides, sensibles et spécifiques particulièrement bien adaptée au domaine biomédical. Dans ce contexte, une ... [more ▼]

La spectroscopie Raman exaltée de surface (SERS) est une technique permettant des analyses rapides, sensibles et spécifiques particulièrement bien adaptée au domaine biomédical. Dans ce contexte, une perspective intéressante est l’utilisation de sondes SERS (combinaison d’un substrat nanostructuré et d’une molécule active en Raman) fonctionnalisées par diverses molécules, permettant le ciblage spécifique de macromolécules biologiques (antigènes, enzymes, ADN, récepteur membranaire, etc). Nous avons développé des sondes SERS utilisant des nanoparticules monométalliques d’or ainsi que des nanoparticules bimétalliques Au@Ag et nous avons étudié leurs performances en présence de différentes molécules actives. Les nanoparticules bimétalliques ont été encapsulées par un polymère afin de leur offrir des possibilités de fonctionnalisation ultérieures. Ces sondes SERS ont été fonctionnalisées et utilisées dans deux applications : la détection d’une enzyme sur support immunochromatographique par fonctionnalisation des sondes avec un anticorps, ainsi que la discrimination à l’aide de l’imagerie spectrale Raman de deux types de cellules cancéreuses par fonctionnalisation des sondes avec l’acide folique. [less ▲]

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