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(218) Production(s) de GERGELY C.
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Biomechanical characterization of a fibrinogen–blood hydrogel for human dental pulp regeneration
Auteur(s): Piglionico Sofia Silvia, Varga B., Pall Orsolya, Romieu Olivier, Gergely C., Cuisinier Frédéric, Levallois Bernard, Panayotov Ivan Vladislavov
(Article) Publié:
Biomaterials Science, vol. p. (2023)
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Organization of collagen fibers and tissue hardening: Markers of fibrotic scarring after spinal cord injury in mice revealed by multiphoton-atomic force microscopy imaging
Auteur(s): Manesco C., Saavedra O., Martin Fernandez M., De Lizaraga J., Varga B., Cloitre T., Gerber Yannick Nicolas, Perrin Florence Evelyne, Gergely C.
(Article) Publié:
Nanomedicine Nanotechnology, Biology And Medicine, vol. p.102699 (2023)
Ref HAL: hal-04195286_v1
DOI: 10.1016/j.nano.2023.102699
Exporter : BibTex | endNote
Résumé: Spinal cord injury is a dramatic disease leading to severe motor, sensitive and autonomic impairments. After injury the axonal regeneration is partly inhibited by the glial scar, acting as a physical and chemical barrier. The scarring process involves microglia, astrocytes and extracellular matrix components, such as collagen, con- structing the fibrotic component of the scar. To investigate the role of collagen, we used a multimodal label-free imaging approach combining multiphoton and atomic force microscopy. The second harmonic generation signal exhibited by fibrillar collagen enabled to specifically monitor it as a biomarker of the lesion. An increase in collagen density and the formation of more tortuous fibers over time after injury are observed. Nano-mechanical investigations revealed a noticeable hardening of the injured area, correlated with collagen fibers' formation. These observations indicate the concomitance of important structural and mechanical modifications during the fibrotic scar evolution.
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Organization of collagen I fibers and tissue hardening: markers of fibrotic scarring after spinal cord injury in mice revealed by multiphoton-atomic force microscopy imaging
Auteur(s): Saavedra O., Manesco C., Martin Fernandez M., De Lizaraga J., Cloitre T., Gerber Yannick, Perrin Florence, Gergely C.
Conference: C'Nano 2023 the Nanoscience Meeting (Poitiers, FR, 2023-03-15)
Ref HAL: hal-04165964_v1
Exporter : BibTex | endNote
Résumé: Spinal cord injury (SCI) is a dramatic disease leading to severe motor, sensitive and autonomic impairments. After the injury, the axonal regeneration is partly inhibited by the glial scar, acting as a physical and chemical barrier[1]. The scarring process involves microglia, astrocytes, and extracellular matrix components, such as collagen, composing the fibrotic part of the scar[2]. To investigate the role of collagen and microglia, we used a multimodal label-free imaging approach combining multiphoton and atomic force microscopies. The second harmonic generation signal exhibited by fibrillar collagen-I enables specifically monitoring it as a biomarker of the lesion. An increase in collagen density and the formation of more curved fibers over time after SCI are observed. Whereas 2-photon excitation microscopy (2PEF) showed the appearance and activation of microglia over millimeters in length near the injured area. Nanomechanical investigations revealed a noticeable hardening of the injured area, correlated with collagen fibers’ development. Additionally, we observed that inhibition of microglial proliferation by oral administration of GW2580 decreased the collagen density at the injured area. These observations indicate the concomitance of relevant structural and mechanical modifications during the fibrotic scar evolution.
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Hyper Rayleigh Scattering from DNA Nucleotides in Aqueous Solution
Auteur(s): Jonin C., Dereniowski Maksymilian, Salmon Estelle, Gergely C., Matczyszyn Katarzyna, Brevet Pierre-François
(Article) Publié:
The Journal Of Chemical Physics, vol. 159 p.054303 (2023)
Ref HAL: hal-04163438_v1
DOI: 10.1063/5.0155821
Exporter : BibTex | endNote
Résumé: Nucleotides are organic compounds consisting of a phosphate group, a nitrogenous base, namely adenine (A), thymine (T), cytosine (C), or guanine (G), and a sugar, here deoxyribose. The magnitude of the first hyperpolarizability of these four DNA nucleotides were determined in aqueous solution with the nonlinear optical technique of Hyper Rayleigh Scattering under non resonant conditions at the fundamental wavelength of 800 nm. The smallest value is found to be esu for thymidine-5'-monophosphate and the highest is esu for 2'-guanosine-5'-monophosphate. Polarization resolved studies were also performed to question the symmetry of the first hyperpolarizability tensor and access the ratio of some elements of the first hyperpolarizability tensor.
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Improving dental epithelial junction on dental implants with bioengineered peptides
Auteur(s): Panayotov Ivan, Vegh Attila Gergely, Martin Fernandez M., Vladimirov Boyan, Larroque Christian, Gergely C., Cuisinier Frédéric Jg, Estephan Elias
(Article) Publié:
Frontiers In Bioengineering And Biotechnology, vol. p. (2023)
Texte intégral en Openaccess :
Ref HAL: hal-04139349_v1
DOI: 10.3389/fbioe.2023.1165853
Exporter : BibTex | endNote
Résumé: Introduction: The functionalization of titanium (Ti) and titanium alloys (Ti6Al4V) implant surfaces via material-specific peptides influence host/biomaterial interaction. The impact of using peptides as molecular linkers between cells and implant material to improve keratinocyte adhesion is reported.Results: The metal binding peptides (MBP-1, MBP-2) SVSVGMKPSPRP and WDPPTLKRPVSP were selected via phage display and combined with laminin-5 or E-cadherin epithelial cell specific peptides (CSP-1, CSP-2) to engineer four metal-cell specific peptides (MCSPs). Single-cell force spectroscopy and cell adhesion experiments were performed to select the most promising candidate. In vivo tests using the dental implant for rats showed that the selected bi functional peptide not only enabled stable cell adhesion on the trans-gingival part of the dental implant but also arrested the unwanted apical migration of epithelial cells.Conclusion: The results demonstrated the outstanding performance of the bioengineered peptide in improving epithelial adhesion to Ti based implants and pointed towards promising new opportunities for applications in clinical practice.
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Properties of dentin, enamel and their junction, studied with Brillouin scattering and compared to Raman microscopy
Auteur(s): Desoutter Alban, Felbacq D., Gergely C., Varga B., Bonnet L., Etienne P., Vialla R., Cuisinier Frédéric, Salehi Hamideh, Rousseau E., Ruffle B.
(Article) Publié:
Archives Of Oral Biology, vol. 152 p.105733 (2023)
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Cardiomyocyte sarcomere length variability: Membrane fluorescence versus second harmonic generation myosin imaging
Auteur(s): Lookin Oleg, de Tombe Pieter, Boulali Najlae, Gergely C., Cloitre T., Cazorla Olivier
(Article) Publié:
Journal Of General Physiology, vol. 155 p.e202213289 (2023)
Texte intégral en Openaccess :
Ref HAL: hal-03959228_v1
DOI: 10.1085/jgp.202213289
Exporter : BibTex | endNote
Résumé: Sarcomere length (SL) and its variation along the myofibril strongly regulate integrated coordinated myocyte contraction. It is therefore important to obtain individual SL properties. Optical imaging by confocal fluorescence (for example, using ANEPPS) or transmitted light microscopy is often used for this purpose. However, this allows for the visualization of structures related to Z-disks only. In contrast, second-harmonic generation (SHG) microscopy visualizes A-band sarcomeric structures directly. Here, we compared averaged SL and its variability in isolated relaxed rat cardiomyocytes by imaging with ANEPPS and SHG. We found that SL variability, evaluated by several absolute and relative measures, is two times smaller using SHG vs. ANEPPS, while both optical methods give the same average (median) SL. We conclude that optical methods with similar optical spatial resolution provide valid estimations of average SL, but the use of SHG microscopy for visualization of sarcomeric A-bands may be the “gold standard” for evaluation of SL variability due to the absence of optical interference between the sarcomere center and non-sarcomeric structures. This contrasts with sarcomere edges where t-tubules may not consistently colocalize to Z-disks. The use of SHG microscopy instead of fluorescent imaging can be a prospective tool to map sarcomere variability both in vitro and in vivo conditions and to reveal its role in the functional behavior of living myocardium.
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