1
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Antonacci G, Vanna R, Ventura M, Schiavone ML, Sobacchi C, Behrouzitabar M, Polli D, Manzoni C, Cerullo G. Birefringence-induced phase delay enables Brillouin mechanical imaging in turbid media. Nat Commun 2024; 15:5202. [PMID: 38898004 PMCID: PMC11187154 DOI: 10.1038/s41467-024-49419-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
Acoustic vibrations of matter convey fundamental viscoelastic information that can be optically retrieved by hyperfine spectral analysis of the inelastic Brillouin scattered light. Increasing evidence of the central role of the viscoelastic properties in biological processes has stimulated the rise of non-contact Brillouin microscopy, yet this method faces challenges in turbid samples due to overwhelming elastic background light. Here, we introduce a common-path Birefringence-Induced Phase Delay (BIPD) filter to disentangle the polarization states of the Brillouin and Rayleigh signals, enabling the rejection of the background light using a polarizer. We demonstrate a 65 dB extinction ratio in a single optical pass collecting Brillouin spectra in extremely scattering environments and across highly reflective interfaces. We further employ the BIPD filter to image bone tissues from a mouse model of osteopetrosis, highlighting altered biomechanical properties compared to the healthy control. Results herald new opportunities in mechanobiology where turbid biological samples remain poorly characterized.
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Affiliation(s)
| | - Renzo Vanna
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Marco Ventura
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | | | - Cristina Sobacchi
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089, Rozzano (Milano), Italy
- CNR-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), UOS di Milano, via Fantoli 16/15, 20138, Milano, Italy
| | - Morteza Behrouzitabar
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Dario Polli
- Specto Photonics, Via Giulio e Corrado Venini 18, 20127, Milano, Italy
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Cristian Manzoni
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy.
| | - Giulio Cerullo
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
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2
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Yang F, Bevilacqua C, Hambura S, Neves A, Gopalan A, Watanabe K, Govendir M, Bernabeu M, Ellenberg J, Diz-Muñoz A, Köhler S, Rapti G, Jechlinger M, Prevedel R. Pulsed stimulated Brillouin microscopy enables high-sensitivity mechanical imaging of live and fragile biological specimens. Nat Methods 2023; 20:1971-1979. [PMID: 37884795 PMCID: PMC10703689 DOI: 10.1038/s41592-023-02054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
Brillouin microscopy is an emerging optical elastography technique capable of assessing mechanical properties of biological samples in a three-dimensional, all-optical and noncontact fashion. The typically weak Brillouin scattering signal can be substantially enhanced via a stimulated Brillouin scattering (SBS) process; however, current implementations require high pump powers, which prohibit applications to photosensitive or live imaging of biological samples. Here we present a pulsed SBS scheme that takes advantage of the nonlinearity of the pump-probe interaction. In particular, we show that the required pump laser power can be decreased ~20-fold without affecting the signal levels or spectral precision. We demonstrate the low phototoxicity and high specificity of our pulsed SBS approach by imaging, with subcellular detail, sensitive single cells, zebrafish larvae, mouse embryos and adult Caenorhabditis elegans. Furthermore, our method permits observing the mechanics of organoids and C. elegans embryos over time, opening up further possibilities for the field of mechanobiology.
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Affiliation(s)
- Fan Yang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China.
| | - Carlo Bevilacqua
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Sebastian Hambura
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ana Neves
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Anusha Gopalan
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Koki Watanabe
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Matt Govendir
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- European Molecular Biology Laboratory Barcelona, Barcelona, Spain
| | - Maria Bernabeu
- European Molecular Biology Laboratory Barcelona, Barcelona, Spain
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Simone Köhler
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Georgia Rapti
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Rome, Italy
| | - Martin Jechlinger
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- MOLIT Institute for Personalized Medicine gGmbH, Heilbronn, Germany
| | - Robert Prevedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany.
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Rome, Italy.
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- German Center for Lung Research (DZL), Heidelberg, Germany.
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3
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Ghosh B, Agarwal K. Viewing life without labels under optical microscopes. Commun Biol 2023; 6:559. [PMID: 37231084 PMCID: PMC10212946 DOI: 10.1038/s42003-023-04934-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023] Open
Abstract
Optical microscopes today have pushed the limits of speed, quality, and observable space in biological specimens revolutionizing how we view life today. Further, specific labeling of samples for imaging has provided insight into how life functions. This enabled label-based microscopy to percolate and integrate into mainstream life science research. However, the use of labelfree microscopy has been mostly limited, resulting in testing for bio-application but not bio-integration. To enable bio-integration, such microscopes need to be evaluated for their timeliness to answer biological questions uniquely and establish a long-term growth prospect. The article presents key label-free optical microscopes and discusses their integrative potential in life science research for the unperturbed analysis of biological samples.
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4
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Bevilacqua C, Gomez JM, Fiuza UM, Chan CJ, Wang L, Hambura S, Eguren M, Ellenberg J, Diz-Muñoz A, Leptin M, Prevedel R. High-resolution line-scan Brillouin microscopy for live imaging of mechanical properties during embryo development. Nat Methods 2023; 20:755-760. [PMID: 36997817 PMCID: PMC10172129 DOI: 10.1038/s41592-023-01822-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 02/17/2023] [Indexed: 04/01/2023]
Abstract
Brillouin microscopy can assess mechanical properties of biological samples in a three-dimensional (3D), all-optical and hence non-contact fashion, but its weak signals often lead to long imaging times and require an illumination dosage harmful for living organisms. Here, we present a high-resolution line-scanning Brillouin microscope for multiplexed and hence fast 3D imaging of dynamic biological processes with low phototoxicity. The improved background suppression and resolution, in combination with fluorescence light-sheet imaging, enables the visualization of the mechanical properties of cells and tissues over space and time in living organism models such as fruit flies, ascidians and mouse embryos.
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Affiliation(s)
- Carlo Bevilacqua
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Juan Manuel Gomez
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ulla-Maj Fiuza
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Systems Bioengineering, MELIS, Universidad Pompeu Fabra, Barcelona, Spain
| | - Chii Jou Chan
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ling Wang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Sebastian Hambura
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Manuel Eguren
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Maria Leptin
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Robert Prevedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Monterotondo, Italy.
- Molecular Medicine Partnership Unit (MMPU), European Molecular Biology Laboratory, Heidelberg, Germany.
- German Center for Lung Research (DZL), Heidelberg, Germany.
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany.
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5
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Rix J, Uckermann O, Kirsche K, Schackert G, Koch E, Kirsch M, Galli R. Correlation of biomechanics and cancer cell phenotype by combined Brillouin and Raman spectroscopy of U87-MG glioblastoma cells. JOURNAL OF THE ROYAL SOCIETY, INTERFACE 2022; 19:20220209. [PMID: 35857926 DOI: 10.1098/rsif.2022.0209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The elucidation of biomechanics furthers our understanding of brain tumour biology. Brillouin spectroscopy is a new optical method that addresses viscoelastic properties down to subcellular resolution in a contact-free manner. Moreover, it can be combined with Raman spectroscopy to obtain co-localized biochemical information. Here, we applied co-registered Brillouin and Raman spectroscopy to U87-MG human glioblastoma cells in vitro. Using two-dimensional and three-dimensional cultures, we related biomechanical properties to local biochemical composition at the subcellular level, as well as the cell phenotype. Brillouin and Raman mapping of adherent cells showed that the nucleus and nucleoli are stiffer than the perinuclear region and the cytoplasm. The biomechanics of the cell cytoplasm is affected by culturing conditions, i.e. cells grown as spheroids are stiffer than adherent cells. Inside the spheroids, the presence of lipid droplets as assessed by Raman spectroscopy revealed higher Brillouin shifts that are not related to a local increase in stiffness, but are due to a higher refractive index combined with a lower mass density. This highlights the importance of locally defined biochemical reference data for a correct interpretation of the Brillouin shift of cells and tissues in future studies investigating the biomechanics of brain tumour models by Brillouin spectroscopy.
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Affiliation(s)
- Jan Rix
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Ortrud Uckermann
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany.,Division of Medical Biology, Department of Psychiatry, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Katrin Kirsche
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Gabriele Schackert
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Edmund Koch
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Matthias Kirsch
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany.,Klinik für Neurochirurgie, Asklepios Kliniken Schildautal, Karl-Herold-Strasse 1, D-38723 Seesen, Germany.,National Center for Tumor Diseases (NCT), Partner Site Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Roberta Galli
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
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6
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Rix J, Rüsing M, Galli R, Golde J, Reitzig S, Eng LM, Koch E. Brillouin and Raman imaging of domain walls in periodically-poled 5%-MgO:LiNbO3. OPTICS EXPRESS 2022; 30:5051-5062. [PMID: 35209476 DOI: 10.1364/oe.447554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Recently, ferroelectric domain walls (DWs) have attracted considerable attention due to their intrinsic topological effects and their huge potential for optoelectronic applications. In contrast, many of the underlying physical properties and phenomena are not well characterized. In this regard, analyzing the vibrational properties, e.g. by Raman spectroscopy, provides direct access to the various local material properties, such as strains, defects or electric fields. While the optical phonon spectra of DWs have been widely investigated in the past, no reports on the acoustic phonon properties of DWs exist. In this work, we present a joint Raman and Brillouin visualization of ferroelectric DWs in the model ferroelectric lithium niobate. This is possible by using a combined Raman and virtually imaged phased array Brillouin setup. Here, we show that DWs can be visualized via frequency shifts observed in the acoustic phonons, as well. The observed contrast then is qualitatively explained by models adapted from Raman spectroscopy. This work, hence, provides a novel route to study ferroelectric DWs and their intrinsic mechanical properties.
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7
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Mechanical mapping of mammalian follicle development using Brillouin microscopy. Commun Biol 2021; 4:1133. [PMID: 34580426 PMCID: PMC8476509 DOI: 10.1038/s42003-021-02662-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/08/2021] [Indexed: 02/08/2023] Open
Abstract
In early mammalian development, the maturation of follicles containing the immature oocytes is an important biological process as the functional oocytes provide the bulk genetic and cytoplasmic materials for successful reproduction. Despite recent work demonstrating the regulatory role of mechanical stress in oocyte growth, quantitative studies of ovarian mechanical properties remain lacking both in vivo and ex vivo. In this work, we quantify the material properties of ooplasm, follicles and connective tissues in intact mouse ovaries at distinct stages of follicle development using Brillouin microscopy, a non-invasive tool to probe mechanics in three-dimensional (3D) tissues. We find that the ovarian cortex and its interior stroma have distinct material properties associated with extracellular matrix deposition, and that intra-follicular mechanical compartments emerge during follicle maturation. Our work provides an alternative approach to study the role of mechanics in follicle morphogenesis and might pave the way for future understanding of mechanotransduction in reproductive biology, with potential implications for infertility diagnosis and treatment.
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8
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Rioboó RJJ, Gontán N, Sanderson D, Desco M, Gómez-Gaviro MV. Brillouin Spectroscopy: From Biomedical Research to New Generation Pathology Diagnosis. Int J Mol Sci 2021; 22:8055. [PMID: 34360822 PMCID: PMC8347166 DOI: 10.3390/ijms22158055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/11/2021] [Accepted: 07/23/2021] [Indexed: 01/06/2023] Open
Abstract
Brillouin spectroscopy has recently gained considerable interest within the biomedical field as an innovative tool to study mechanical properties in biology. The Brillouin effect is based on the inelastic scattering of photons caused by their interaction with thermodynamically driven acoustic modes or phonons and it is highly dependent on the material's elasticity. Therefore, Brillouin is a contactless, label-free optic approach to elastic and viscoelastic analysis that has enabled unprecedented analysis of ex vivo and in vivo mechanical behavior of several tissues with a micrometric resolution, paving the way to a promising future in clinical diagnosis. Here, we comprehensively review the different studies of this fast-moving field that have been performed up to date to provide a quick guide of the current literature. In addition, we offer a general view of Brillouin's biomedical potential to encourage its further development to reach its implementation as a feasible, cost-effective pathology diagnostic tool.
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Affiliation(s)
- Rafael J. Jiménez Rioboó
- Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), C/Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain;
| | - Nuria Gontán
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
| | - Daniel Sanderson
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
| | - Manuel Desco
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029 Madrid, Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Maria Victoria Gómez-Gaviro
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
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9
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Correa N, Alunni Cardinali M, Bailey M, Fioretto D, Pudney PDA, Palombo F. Brillouin microscopy for the evaluation of hair micromechanics and effect of bleaching. JOURNAL OF BIOPHOTONICS 2021; 14:e202000483. [PMID: 33768666 DOI: 10.1002/jbio.202000483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/19/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Brillouin microscopy is a new form of optical elastography and an emerging technique in mechanobiology and biomedical physics. It was applied here to map the viscoelastic properties of human hair and to determine the effect of bleaching on hair properties. For hair samples, longitudinal measurements (i.e. along the fibre axis) revealed peaks at 18.7 and 20.7 GHz at the location of the cuticle and cortex, respectively. For hair treated with a bleaching agent, the frequency shifts for the cuticle and cortex were 19.7 and 21.0 GHz, respectively, suggesting that bleaching increases the cuticle modulus and-to a minor extent-the cortex modulus. These results demonstrate the capability of Brillouin spectroscopy to address questions on micromechanical properties of hair and to validate the effect of applied treatments.
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Affiliation(s)
- Noemi Correa
- School of Physics, University of Exeter, Exeter, UK
| | | | | | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Perugia, Italy
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10
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Bailey M, Gardner B, Alunni-Cardinali M, Caponi S, Fioretto D, Stone N, Palombo F. Predicting the Refractive Index of Tissue Models Using Light Scattering Spectroscopy. APPLIED SPECTROSCOPY 2021; 75:574-580. [PMID: 33319606 PMCID: PMC8114435 DOI: 10.1177/0003702820984482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
In this work, we report the application of Raman microspectroscopy for analysis of the refractive index of a range of tissue phantoms. Using both a custom-developed setup with visible laser source and a commercial microspectrometer with near infrared laser, we measured the Raman spectra of gelatin hydrogels at various concentrations. By building a calibration curve from measured refractometry data and Raman scattering intensity for different vibrational modes of the hydrogel, we were able to predict the refractive indices of the gels from their Raman spectra. This work highlights the importance of a correlative approach through Brillouin-Raman microspectroscopy for the mechano-chemical analysis of biologically relevant samples.
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Affiliation(s)
- Michelle Bailey
- School of Physics and Astronomy, University of Exeter, Exeter, UK
| | - Benjamin Gardner
- School of Physics and Astronomy, University of Exeter, Exeter, UK
| | | | - Silvia Caponi
- CNR-IOM – Istituto Officina dei Materiali – Research Unit in Perugia, c/o Department of Physics and Geology, University of Perugia, Perugia, Italy
| | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Perugia, Italy
| | - Nick Stone
- School of Physics and Astronomy, University of Exeter, Exeter, UK
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11
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Ryu S, Martino N, Kwok SJJ, Bernstein L, Yun SH. Label-free histological imaging of tissues using Brillouin light scattering contrast. BIOMEDICAL OPTICS EXPRESS 2021; 12:1437-1448. [PMID: 33796364 PMCID: PMC7984781 DOI: 10.1364/boe.414474] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 05/06/2023]
Abstract
Brillouin light scattering offers a unique label-free approach to measure biomechanical properties non-invasively. While this technique is used in biomechanical analysis of cells and tissues, its potential for visualizing structural features of tissues based on the biomechanical contrast has not been much exploited. Here, we present high-resolution Brillouin microscopy images of four basic tissue types: muscular, connective, epithelial, and nervous tissues. The Brillouin contrast distinguishes between muscle fiber cells and endomysium in skeletal muscle and reveals chondrocytes along with spatially varying stiffness of the extracellular matrix in articular cartilage. The hydration-sensitive contrast can visualize the stratum corneum, epidermis, and dermis in the skin epithelium. In brain tissues, the Brillouin images show the mechanical heterogeneity across the cortex and deeper regions. This work demonstrates the versatility of using the Brillouin shift as histological contrast for examining intact tissue substructures via longitudinal modulus without the need for laborious tissue processing steps.
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Affiliation(s)
- Seungmi Ryu
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne St., Cambridge, MA 02139, USA
- National Center for Advancing Translational Sciences, National Institute of Health, Rockville, MD 20850, USA
- These authors contributed equally to this work
| | - Nicola Martino
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne St., Cambridge, MA 02139, USA
- These authors contributed equally to this work
| | - Sheldon J. J. Kwok
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne St., Cambridge, MA 02139, USA
- Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Liane Bernstein
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne St., Cambridge, MA 02139, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Seok-Hyun Yun
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne St., Cambridge, MA 02139, USA
- Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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12
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Wu H, Zhao W, Su Y, Qiu L, Wang Y, Ni H. Divided-aperture confocal Brillouin microscopy for simultaneous high-precision topographic and mechanical mapping. OPTICS EXPRESS 2020; 28:31821-31831. [PMID: 33115147 DOI: 10.1364/oe.405458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
Confocal Brillouin microscopy (CBM) is a novel and powerful technique for providing non-contact and direct readout of the micro-mechanical properties of a material, and thus used in a broad range of applications, including biological tissue detection, cell imaging, and material characterization in manufacturing. However, conventional CBMs have not enabled high precision mechanical mapping owing to the limited depth of focus and are subject to system drift during long-term measurements. In this paper, a divided-aperture confocal Brillouin microscopy (DCBM) is proposed to improve the axial focusing capability, stability, and extinction ratio of CBM. We exploit high-sensitivity divided-aperture confocal technology to achieve an unprecedented 100-fold enhancement in the axial focusing sensitivity of the existing CBMs, reaching 5 nm, and to enhance system stability. In addition, the dark-field setup improves the extinction ratio by 20 dB. To the best of our knowledge, our method achieves the first in situ topographic imaging and mechanical mapping of the sample and provides a new approach for Brillouin scattering applications in material characterization.
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13
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Pérez-Cota F, La Cavera III S, Naznin S, Fuentes-Domínguez R, Smith RJ, Clark M. Apparent attenuation by opto-acoustic defocus in phonon microscopy. PHOTOACOUSTICS 2020; 19:100180. [PMID: 32489857 PMCID: PMC7262445 DOI: 10.1016/j.pacs.2020.100180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 01/10/2020] [Accepted: 03/30/2020] [Indexed: 05/20/2023]
Abstract
Understanding the mechanical properties of biological cells is a challenging problem for the life sciences partly because there are limited methods for mapping elasticity with high resolution. Phonon microscopy is a form of Brillouin light scattering which uses coherent phonons for imaging with elasticity-related contrast, phonon resolution and without labels. It can measure material properties such as sound velocity, acoustic impedance and attenuation. To use it as a contrast mechanism in microscopy, high numerical aperture (NA) lenses are key to high resolution. However, increasing NA induces apparent attenuation, a premature decay of the detected signal. To reduce signal decay and quantify the sound attenuation coefficient in cells, it is necessary to understand the mechanisms that affect signal decay. Here we define opto-acoustic defocus as a signal decay mechanism and propose methods to achieve quantitative sound attenuation measurements, and to optimise in-depth imaging at high resolution which is crucial for cell imaging.
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14
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Remer I, Shaashoua R, Shemesh N, Ben-Zvi A, Bilenca A. High-sensitivity and high-specificity biomechanical imaging by stimulated Brillouin scattering microscopy. Nat Methods 2020; 17:913-916. [PMID: 32747769 DOI: 10.1038/s41592-020-0882-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 05/27/2020] [Indexed: 01/04/2023]
Abstract
Label-free, non-contact imaging with mechanical contrast and optical sectioning is a substantial challenge in microscopy. Spontaneous Brillouin scattering microscopy meets this challenge, but encounters a trade-off between acquisition speed and the specificity for biomechanical constituents with overlapping Brillouin bands. Stimulated Brillouin scattering microscopy overcomes this trade-off and enables the cross-sectional imaging of live Caenorhabditis elegans at the organ and subcellular levels, with both elasticity and viscosity contrasts at high specificity and with practical recording times.
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Affiliation(s)
- Itay Remer
- Biomedical Engineering Department, Ben-Gurion University of the Negev, Be'er-Sheva, Israel. .,Agilent Research Laboratories, Petach Tikva, Israel.
| | - Roni Shaashoua
- Biomedical Engineering Department, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
| | - Netta Shemesh
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Anat Ben-Zvi
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Alberto Bilenca
- Biomedical Engineering Department, Ben-Gurion University of the Negev, Be'er-Sheva, Israel. .,Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be'er-Sheva, Israel.
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15
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Follain G, Herrmann D, Harlepp S, Hyenne V, Osmani N, Warren SC, Timpson P, Goetz JG. Fluids and their mechanics in tumour transit: shaping metastasis. Nat Rev Cancer 2020; 20:107-124. [PMID: 31780785 DOI: 10.1038/s41568-019-0221-x] [Citation(s) in RCA: 214] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/21/2019] [Indexed: 02/07/2023]
Abstract
Metastasis is a dynamic succession of events involving the dissemination of tumour cells to distant sites within the body, ultimately reducing the survival of patients with cancer. To colonize distant organs and, therefore, systemically disseminate within the organism, cancer cells and associated factors exploit several bodily fluid systems, which provide a natural transportation route. Indeed, the flow mechanics of the blood and lymphatic circulatory systems can be co-opted to improve the efficiency of cancer cell transit from the primary tumour, extravasation and metastatic seeding. Flow rates, vessel size and shear stress can all influence the survival of cancer cells in the circulation and control organotropic seeding patterns. Thus, in addition to using these fluids as a means to travel throughout the body, cancer cells exploit the underlying physical forces within these fluids to successfully seed distant metastases. In this Review, we describe how circulating tumour cells and tumour-associated factors leverage bodily fluids, their underlying forces and imposed stresses during metastasis. As the contribution of bodily fluids and their mechanics raises interesting questions about the biology of the metastatic cascade, an improved understanding of this process might provide a new avenue for targeting cancer cells in transit.
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Affiliation(s)
- Gautier Follain
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - David Herrmann
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Sébastien Harlepp
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Vincent Hyenne
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- CNRS SNC 505, Strasbourg, France
| | - Naël Osmani
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Sean C Warren
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Paul Timpson
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.
| | - Jacky G Goetz
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France.
- Université de Strasbourg, Strasbourg, France.
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France.
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16
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Elsayad K. Optical imaging spectroscopy for plant research: more than a colorful picture. CURRENT OPINION IN PLANT BIOLOGY 2019; 52:77-85. [PMID: 31520788 DOI: 10.1016/j.pbi.2019.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 05/24/2023]
Abstract
Optical imaging is a routine and indispensable tool in plant research. Here we review different emerging spectrally resolved optical imaging approaches and the wealth of information they can be used to obtain pertaining to the underlying chemistry, structure and mechanics of plants.
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Affiliation(s)
- Kareem Elsayad
- Advanced Microscopy, VBCF, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna A-1030, Austria.
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17
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Brillouin microscopy: an emerging tool for mechanobiology. Nat Methods 2019; 16:969-977. [PMID: 31548707 DOI: 10.1038/s41592-019-0543-3] [Citation(s) in RCA: 192] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 07/29/2019] [Indexed: 12/14/2022]
Abstract
The role and importance of mechanical properties of cells and tissues in cellular function, development and disease has widely been acknowledged, however standard techniques currently used to assess them exhibit intrinsic limitations. Recently, Brillouin microscopy, a type of optical elastography, has emerged as a non-destructive, label- and contact-free method that can probe the viscoelastic properties of biological samples with diffraction-limited resolution in 3D. This led to increased attention amongst the biological and medical research communities, but it also sparked debates about the interpretation and relevance of the measured physical quantities. Here, we review this emerging technology by describing the underlying biophysical principles and discussing the interpretation of Brillouin spectra arising from heterogeneous biological matter. We further elaborate on the technique's limitations, as well as its potential for gaining insights in biology, in order to guide interested researchers from various fields.
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18
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Abstract
Brillouin spectroscopy and imaging are emerging techniques in analytical science, biophotonics, and biomedicine. They are based on Brillouin light scattering from acoustic waves or phonons in the GHz range, providing a nondestructive contactless probe of the mechanics on a microscale. Novel approaches and applications of these techniques to the field of biomedical sciences are discussed, highlighting the theoretical foundations and experimental methods that have been developed to date. Acknowledging that this is a fast moving field, a comprehensive account of the relevant literature is critically assessed here.
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Affiliation(s)
- Francesca Palombo
- School
of Physics and Astronomy, University of
Exeter, Stocker Road, EX4 4QL Exeter, U.K.
| | - Daniele Fioretto
- Department
of Physics and Geology, University of Perugia, via Alessandro Pascoli, I-06123 Perugia, Italy
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19
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Riobóo RJJ, Desco M, Gómez-Gaviro MV. Impact of optical tissue clearing on the Brillouin signal from biological tissue samples. BIOMEDICAL OPTICS EXPRESS 2019; 10:2674-2683. [PMID: 31259043 PMCID: PMC6583338 DOI: 10.1364/boe.10.002674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/24/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Brillouin spectroscopy is a well-established technology in condensed matter physics to characterize the mechanical properties of inert materials, and it has been extended very recently to the study of biological samples. Transparency is beneficial for samples to be properly analyzed by Brillouin spectroscopy. Here, we explored the efficacy of optical tissue clearing techniques to improve the acquisition of Brillouin spectra from biological tissues in order to analyze their biomechanical properties. We describe the first application of Brillouin scattering to optically cleared biological tissues with CUBIC protocol. We conclude that, within the range of error, tissue clearing does not modify the mechanical properties of the studied biological tissues.
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Affiliation(s)
- Rafael J. Jiménez Riobóo
- Instituto de Ciencia de Materiales de Madrid ((ICMM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - Manuel Desco
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Doctor Esquerdo 46, 28007 Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, 28911 Leganés, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029 Madrid, Spain
- Centro de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 28029 Madrid, Spain
| | - María Victoria Gómez-Gaviro
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Doctor Esquerdo 46, 28007 Madrid, Spain
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, 28911 Leganés, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029 Madrid, Spain
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20
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Coppola S, Schmidt T, Ruocco G, Antonacci G. Quantifying cellular forces and biomechanical properties by correlative micropillar traction force and Brillouin microscopy. BIOMEDICAL OPTICS EXPRESS 2019; 10:2202-2212. [PMID: 31149370 PMCID: PMC6524592 DOI: 10.1364/boe.10.002202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Cells sense and respond to external physical forces and substrate rigidity by regulating their cell shape, internal cytoskeletal tension, and stiffness. Here we show that the combination of micropillar traction force and noncontact Brillouin microscopy provides access to cell-generated forces and intracellular mechanical properties at optical resolution. Actin-rich cytoplasmic domains of 3T3 fibroblasts showed significantly higher Brillouin shifts, indicating a potential increase in stiffness when adhering on fibronectin-coated glass compared to soft PDMS micropillars. Our findings demonstrate the complementarity of micropillar traction force and Brillouin microscopy to better understand the relation between cell force generation and the intracellular mechanical properties.
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Affiliation(s)
- Stefano Coppola
- Physics of Life Processes - Kamerlingh Onnes-Huygens Laboratory, Leiden Institute of Physics, Leiden University, Leiden,
The Netherlands
| | - Thomas Schmidt
- Physics of Life Processes - Kamerlingh Onnes-Huygens Laboratory, Leiden Institute of Physics, Leiden University, Leiden,
The Netherlands
| | - Giancarlo Ruocco
- Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia, Rome,
Italy
| | - Giuseppe Antonacci
- Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia, Rome,
Italy
- Photonics Research Group, Ghent University - imec, Ghent,
Belgium
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21
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Mercatelli R, Mattana S, Capozzoli L, Ratto F, Rossi F, Pini R, Fioretto D, Pavone FS, Caponi S, Cicchi R. Morpho-mechanics of human collagen superstructures revealed by all-optical correlative micro-spectroscopies. Commun Biol 2019; 2:117. [PMID: 30937399 PMCID: PMC6435656 DOI: 10.1038/s42003-019-0357-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 02/05/2019] [Indexed: 12/18/2022] Open
Abstract
In every biological tissue, morphological and topological properties strongly affect its mechanical features and behaviour, so that ultrastructure, composition and mechanical parameters are intimately connected. Overall, it is their correct interplay that guarantees the tissue functionality. The development of experimental methods able to correlate these properties would open new opportunities both in the biological and the biomedical fields. Here, we report a correlative study intended to map supramolecular morphology, biochemical composition and viscoelastic parameters of collagen by all-optical microscopies. In particular, using human corneal tissue as a benchmark, we correlate Second-Harmonic Generation maps with mechanical and biochemical imaging obtained by Brillouin and Raman micro-spectroscopy. The study highlights how subtle variations in supramolecular organization originate the peculiar mechanical behavior of different subtypes of corneal lamellae. The presented methodology paves the way to the non-invasive assessment of tissue morpho-mechanics in biological as well as synthetic materials.
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Affiliation(s)
- Raffaella Mercatelli
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
| | - Sara Mattana
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- Department of Physics and Geology, University of Perugia, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Laura Capozzoli
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
- Center of Electron Microscopy “Laura Bonzi” (Ce.M.E), Institute of Chemistry of Organometallic Compounds, National Research Council (CNR-ICCOM), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Fulvio Ratto
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Francesca Rossi
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Roberto Pini
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Via Alessandro Pascoli, I-06123 Perugia, Italy
- CEMIN-Center of Excellence for Innovative Nanostructured Material, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Francesco Saverio Pavone
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- Department of Physics, University of Florence, Via Giovanni Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Silvia Caponi
- Institute of Materials, National Research Council (CNR-IOM), Unit of Perugia, c/o Department of Physics and Geology, University of Perugia, Via A. Pascoli, I-06123 Perugia, Italy
| | - Riccardo Cicchi
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
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22
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Fioretto D, Caponi S, Palombo F. Brillouin-Raman mapping of natural fibers with spectral moment analysis. BIOMEDICAL OPTICS EXPRESS 2019; 10:1469-1474. [PMID: 30891360 PMCID: PMC6420284 DOI: 10.1364/boe.10.001469] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/10/2019] [Indexed: 05/08/2023]
Abstract
Brillouin spectroscopy has emerged as a novel analytical tool for biophotonic research and applications. It operates on a microscopic scale and in the GHz spectral range, providing a new spatial and frequency window for the analysis of the materials elasticity. Here we investigate spectral moments calculation as a means of analysing Brillouin and Raman spectra, providing rapid access to peak intensity and frequency shift, with robust application to fast scanning measurements. This work demonstrates the potential of the method, especially in the case of micro-structured samples, typical of bio-medical applications.
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Affiliation(s)
- Daniele Fioretto
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy
| | - Silvia Caponi
- Institute of Materials, National Research Council (IOM-CNR), Unit of Perugia, c/o Department of Physics and Geology, University of Perugia, Perugia, Italy
| | - Francesca Palombo
- School of Physics and Astronomy, University of Exeter, Stocker Road, EX4 4QL Exeter, United Kingdom
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23
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Correa N, Harding S, Bailey M, Brasselet S, Palombo F. Image analysis applied to Brillouin images of tissue-mimicking collagen gelatins. BIOMEDICAL OPTICS EXPRESS 2019; 10:1329-1338. [PMID: 30891349 PMCID: PMC6420274 DOI: 10.1364/boe.10.001329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/13/2019] [Accepted: 01/20/2019] [Indexed: 06/09/2023]
Abstract
Brillouin spectroscopy is an emerging analytical tool in biomedical and biophysical sciences. It probes viscoelasticity through the propagation of thermally induced acoustic waves at gigahertz frequencies. Brillouin light scattering (BLS) measurements have traditionally been performed using multipass Fabry-Pérot interferometers, which have high contrast and resolution, however, as they are scanning spectrometers they often require long acquisition times in poorly scattering media. In the last decade, a new concept of Brillouin spectrometer has emerged, making use of highly angle-dispersive virtually imaged phase array (VIPA) etalons, which enable fast acquisition times for minimally turbid materials, when high contrast is not imperative. The ability to acquire Brillouin spectra rapidly, together with long term system stability, make this system a viable candidate for use in biomedical applications, especially to probe live cells and tissues. While various methods are being developed to improve system contrast and speed, little work has been published discussing the details of imaging data analysis and spectral processing. Here we present a method that we developed for the automated retrieval of Brillouin line shape parameters from imaging data sets acquired with a dual-stage VIPA Brillouin microscope. We applied this method for the first time to BLS measurements of collagen gelatin hydrogels at different hydration levels and cross-linker concentrations. This work demonstrates that it is possible to obtain the relevant information from Brillouin spectra using software for real-time high-accuracy analysis.
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Affiliation(s)
- Noemi Correa
- School of Physics and Astronomy, University of Exeter, Stocker Road, EX4 4QL Exeter, UK
| | | | - Michelle Bailey
- School of Physics and Astronomy, University of Exeter, Stocker Road, EX4 4QL Exeter, UK
| | - Sophie Brasselet
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Francesca Palombo
- School of Physics and Astronomy, University of Exeter, Stocker Road, EX4 4QL Exeter, UK
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24
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Palombo F, Masia F, Mattana S, Tamagnini F, Borri P, Langbein W, Fioretto D. Hyperspectral analysis applied to micro-Brillouin maps of amyloid-beta plaques in Alzheimer's disease brains. Analyst 2018; 143:6095-6102. [PMID: 30460364 PMCID: PMC6336087 DOI: 10.1039/c8an01291a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
A recent investigation on the architecture and chemical composition of amyloid-β (Aβ) plaques in ex vivo histological sections of an Aβ-overexpressing transgenic mouse hippocampus has shed light on the infrared light signature of cell-activation related biomarkers of Alzheimer's disease. A correlation was highlighted between the biomechanical properties detected by Brillouin microscopy and the molecular make-up of Aβ plaques provided by FTIR spectroscopic imaging and Raman microscopy (with correlative immunofluorescence imaging) in this animal model of the disease. In the Brillouin spectra of heterogeneous materials such as biomedical samples, peaks are likely the result of multiple contributions, more or less overlaid on a spatial and spectral scale. The ability to disentangle these contributions is very important as it may give access to discrete components that would otherwise be buried within the Brillouin peak envelope. Here, we applied an unsupervised non-negative matrix factorization method to analyse the spontaneous Brillouin microscopy maps of Aβ plaques in transgenic mouse hippocampal sections. The method has already been proven successful in decomposing chemical images and is applied here for the first time to acoustic maps acquired with a Fabry-Perot Brillouin microscope. We extracted and visualised a decrease in tissue rigidity from the core through to the periphery of the plaque, with spatially distinct components that we assigned to specific entities. This work demonstrates that it is possible to reveal the structure and mechanical properties of Aβ plaques, with details visualized by the projection of the mechanical contrast into a few relevant channels.
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Affiliation(s)
- Francesca Palombo
- University of Exeter, School of Physics and Astronomy, Exeter EX4 4QL, UK.
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25
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Antonacci G, de Turris V, Rosa A, Ruocco G. Background-deflection Brillouin microscopy reveals altered biomechanics of intracellular stress granules by ALS protein FUS. Commun Biol 2018; 1:139. [PMID: 30272018 PMCID: PMC6131551 DOI: 10.1038/s42003-018-0148-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/14/2018] [Indexed: 01/01/2023] Open
Abstract
Altered cellular biomechanics have been implicated as key photogenic triggers in age-related diseases. An aberrant liquid-to-solid phase transition, observed in in vitro reconstituted droplets of FUS protein, has been recently proposed as a possible pathogenic mechanism for amyotrophic lateral sclerosis (ALS). Whether such transition occurs in cell environments is currently unknown as a consequence of the limited measuring capability of the existing techniques, which are invasive or lack of subcellular resolution. Here we developed a non-contact and label-free imaging method, named background-deflection Brillouin microscopy, to investigate the three-dimensional intracellular biomechanics at a sub-micron resolution. Our method exploits diffraction to achieve an unprecedented 10,000-fold enhancement in the spectral contrast of single-stage spectrometers, enabling, to the best of our knowledge, the first direct biomechanical analysis on intracellular stress granules containing ALS mutant FUS protein in fixed cells. Our findings provide fundamental insights on the critical aggregation step underlying the neurodegenerative ALS disease.
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Affiliation(s)
- Giuseppe Antonacci
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy.
| | - Valeria de Turris
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Alessandro Rosa
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
- Department of Biology and Biotechnology Charles Darwin, University of Rome"Sapienza", Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
- Department of Physics, University of Rome "Sapienza", Rome, Italy
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26
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Akilbekova D, Ogay V, Yakupov T, Sarsenova M, Umbayev B, Nurakhmetov A, Tazhin K, Yakovlev VV, Utegulov ZN. Brillouin spectroscopy and radiography for assessment of viscoelastic and regenerative properties of mammalian bones. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-11. [PMID: 30264554 PMCID: PMC8357194 DOI: 10.1117/1.jbo.23.9.097004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/15/2018] [Indexed: 05/20/2023]
Abstract
Biomechanical properties of mammalian bones, such as strength, toughness, and plasticity, are essential for understanding how microscopic-scale mechanical features can link to macroscale bones' strength and fracture resistance. We employ Brillouin light scattering (BLS) microspectroscopy for local assessment of elastic properties of bones under compression and the efficacy of the tissue engineering approach based on heparin-conjugated fibrin (HCF) hydrogels, bone morphogenic proteins, and osteogenic stem cells in the regeneration of the bone tissues. BLS is noninvasive and label-free modality for probing viscoelastic properties of tissues that can give information on structure-function properties of normal and pathological tissues. Results showed that MCS and BPMs are critically important for regeneration of elastic and viscous properties, respectively, HCF gels containing combination of all factors had the best effect with complete defect regeneration at week nine after the implantation of bone grafts and that the bones with fully consolidated fractures have higher values of elastic moduli compared with defective bones.
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Affiliation(s)
- Dana Akilbekova
- Nazarbayev University, National Laboratory Astana, Astana, Kazakhstan
- Nazarbayev University, School of Engineering, Department of Chemical Engineering, Astana, Kazakhstan
- Address all correspondence to: Dana Akilbekova, E-mail: ; Zhandos N. Utegulov, E-mail:
| | - Vyacheslav Ogay
- National Center for Biotechnology, Stem Cell Laboratory, Astana, Kazakhstan
| | - Talgat Yakupov
- Nazarbayev University, Department of Physics, School of Science and Technology, Astana, Kazakhstan
| | - Madina Sarsenova
- National Center for Biotechnology, Stem Cell Laboratory, Astana, Kazakhstan
| | - Bauyrzhan Umbayev
- Nazarbayev University, National Laboratory Astana, Astana, Kazakhstan
| | - Asset Nurakhmetov
- Research Institute of Traumatology and Orthopedics, Astana, Kazakhstan
| | - Kairat Tazhin
- Research Institute of Traumatology and Orthopedics, Astana, Kazakhstan
| | - Vladislav V. Yakovlev
- Texas A&M University, Department of Biomedical Engineering and Department of Physics and Astronomy, College Station, Texas, United States
| | - Zhandos N. Utegulov
- Nazarbayev University, Department of Physics, School of Science and Technology, Astana, Kazakhstan
- Address all correspondence to: Dana Akilbekova, E-mail: ; Zhandos N. Utegulov, E-mail:
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Yeast Biofilm as a Bridge Between Medical and Environmental Microbiology Across Different Detection Techniques. Infect Dis Ther 2018; 7:27-34. [PMID: 29549654 PMCID: PMC5856731 DOI: 10.1007/s40121-018-0191-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Indexed: 10/25/2022] Open
Abstract
Medical and environmental microbiology have two distinct, although very short, histories stemming, the first from the pioneering works of Sommelweiss, Pasteur, Lister and Koch, the second mainly from the studies of Bejerink and Winogradsky. These two branches of microbiology evolved and specialized separately producing distinct communities and evolving rather different approaches and techniques. The evidence accumulated in recent decades indicate that indeed most of the medically relevant microorganisms have a short circulation within the nosocomial environment and a larger one involving the external, i.e. non-nosocomial, and the hospital environments. This evidence suggests that the differences between approaches should yield to a convergent approach aimed at solving the increasing problem represented by infectious diseases for the increasingly less resistant human communities. Microbial biofilm is one of the major systems used by these microbes to resist the harsh conditions of the natural and anthropic environment, and the even worse ones related to medical settings. This paper presents a brief outline of the converging interest of both environmental and medical microbiology toward a better understanding of microbial biofilm and of the various innovative techniques that can be employed to characterize, in a timely and quantitative manner, these complex structures. Among these, micro-Raman along with micro-Brillouin offer high hopes of describing biofilms both at the subcellular and supercellular level, with the possibility of characterizing the various landscapes of the different biofilms. The possibility of adding a taxonomic identification of the cells comprising the biofilm is a complex aspect presenting several technical issues that will require further studies in the years to come.
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Mattana S, Mattarelli M, Urbanelli L, Sagini K, Emiliani C, Serra MD, Fioretto D, Caponi S. Non-contact mechanical and chemical analysis of single living cells by microspectroscopic techniques. LIGHT, SCIENCE & APPLICATIONS 2018; 7:17139. [PMID: 30839528 PMCID: PMC6060066 DOI: 10.1038/lsa.2017.139] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/23/2017] [Accepted: 10/08/2017] [Indexed: 05/04/2023]
Abstract
Innovative label-free microspectroscopy, which can simultaneously collect Brillouin and Raman signals, is used to characterize the viscoelastic properties and chemical composition of living cells with sub-micrometric resolution. The unprecedented statistical accuracy of the data combined with the high-frequency resolution and the high contrast of the recently built experimental setup permits the study of single living cells immersed in their buffer solution by contactless measurements. The Brillouin signal is deconvoluted in the buffer and the cell components, thereby revealing the mechanical heterogeneity inside the cell. In particular, a 20% increase is observed in the elastic modulus passing from the plasmatic membrane to the nucleus as distinguished by comparison with the Raman spectroscopic marker. Brillouin line shape analysis is even more relevant for the comparison of cells under physiological and pathological conditions. Following oncogene expression, cells show an overall reduction in the elastic modulus (15%) and apparent viscosity (50%). In a proof-of-principle experiment, the ability of this spectroscopic technique to characterize subcellular compartments and distinguish cell status was successfully tested. The results strongly support the future application of this technique for fundamental issues in the biomedical field.
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Affiliation(s)
- Sara Mattana
- Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
| | - Maurizio Mattarelli
- Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
| | - Lorena Urbanelli
- Laboratory of Biochemistry and Molecular Biology, Department of Chemistry, Biology and Biotechnology, University of Perugia, via del Giochetto, Perugia I-06123, Italy
| | - Krizia Sagini
- Laboratory of Biochemistry and Molecular Biology, Department of Chemistry, Biology and Biotechnology, University of Perugia, via del Giochetto, Perugia I-06123, Italy
| | - Carla Emiliani
- Laboratory of Biochemistry and Molecular Biology, Department of Chemistry, Biology and Biotechnology, University of Perugia, via del Giochetto, Perugia I-06123, Italy
- CEMIN-Center of Excellence for Innovative Nanostructured Material, Perugia I-06123, Italy
| | - Mauro Dalla Serra
- Istituto di Biofisica CNR (IBF-CNR), Unità di Trento, and FBK, Via Sommarive 18, Trento 38123, Italy
| | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
- CEMIN-Center of Excellence for Innovative Nanostructured Material, Perugia I-06123, Italy
| | - Silvia Caponi
- Istituto Officina dei Materiali del CNR (CNR-IOM)—Unità di Perugia, c/o Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
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29
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Mattana S, Caponi S, Tamagnini F, Fioretto D, Palombo F. Viscoelasticity of amyloid plaques in transgenic mouse brain studied by Brillouin microspectroscopy and correlative Raman analysis. JOURNAL OF INNOVATIVE OPTICAL HEALTH SCIENCES 2017; 10:1742001. [PMID: 29151920 PMCID: PMC5687568 DOI: 10.1142/s1793545817420019] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Amyloidopathy is one of the most prominent hallmarks of Alzheimer's disease (AD), the leading cause of dementia worldwide, and is characterized by the accumulation of amyloid plaques in the brain parenchyma. The plaques consist of abnormal deposits mainly composed of an aggregation-prone protein fragment, β-amyloid 1-40/1-42, into the extracellular matrix. Brillouin microspectroscopy is an all-optical contactless technique that is based on the interaction between visible light and longitudinal acoustic waves or phonons, giving access to the viscoelasticity of a sample on a subcellular scale. Here, we describe the first application of micromechanical mapping based on Brillouin scattering spectroscopy to probe the stiffness of individual amyloid plaques in the hippocampal part of the brain of a β-amyloid overexpressing transgenic mouse. Correlative analysis based on Brillouin and Raman microspectroscopy showed that amyloid plaques have a complex structure with a rigid core of β-pleated sheet conformation (β-amyloid) protein surrounded by a softer ring-shaped region richer in lipids and other protein conformations. These preliminary results give a new insight into the plaque biophysics and biomechanics, and a valuable contrast mechanism for the study and diagnosis of amyloidopathy.
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Affiliation(s)
- Sara Mattana
- Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
| | - Silvia Caponi
- Istituto Officina dei Materiali del CNR (CNR-IOM) - Unità di Perugia Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
| | - Francesco Tamagnini
- Hatherly Laboratories, Medical School University of Exeter, Exeter EX4 4PS, UK
| | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
| | - Francesca Palombo
- School of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK
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30
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Remer I, Cohen L, Bilenca A. High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis. J Vis Exp 2017. [PMID: 28994794 DOI: 10.3791/55527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as aqueous solutions and biomaterials, with fast acquisition times. Here, we discuss the assembly and operation of a Brillouin spectrometer that uses stimulated Brillouin scattering (SBS) to measure stimulated Brillouin gain (SBG) spectra of water and lipid emulsion-based tissue-like samples in transmission mode with <10 MHz spectral-resolution and <35 MHz Brillouin-shift measurement precision at <100 ms. The spectrometer consists of two nearly counter-propagating continuous-wave (CW) narrow-linewidth lasers at 780 nm whose frequency detuning is scanned through the material Brillouin shift. By using an ultra-narrowband hot rubidium-85 vapor notch filter and a phase-sensitive detector, the signal-to-noise-ratio of the SBG signal is significantly enhanced compared to that obtained with existing CW-SBS spectrometers. This improvement enables measurement of SBG spectra with up to 100-fold faster acquisition times, thereby facilitating high spectral-resolution and high-precision Brillouin analysis of soft materials at high speed.
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Affiliation(s)
- Itay Remer
- Biomedical Engineering Department, Ben-Gurion University of the Negev
| | - Lear Cohen
- Biomedical Engineering Department, Ben-Gurion University of the Negev
| | - Alberto Bilenca
- Biomedical Engineering Department, Ben-Gurion University of the Negev; Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev;
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31
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Mattana S, Alunni Cardinali M, Caponi S, Casagrande Pierantoni D, Corte L, Roscini L, Cardinali G, Fioretto D. High-contrast Brillouin and Raman micro-spectroscopy for simultaneous mechanical and chemical investigation of microbial biofilms. Biophys Chem 2017; 229:123-129. [PMID: 28684254 DOI: 10.1016/j.bpc.2017.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 12/18/2022]
Abstract
Mechanical mapping with chemical specificity of biological samples is now made possible by joint micro-Brillouin and micro-Raman measurements. In this work, thanks to the unprecedented contrast of a new tandem Fabry-Perot interferometer, we demonstrate simultaneous detection of Brillouin and Raman spectra from different Candida biofilms. Our proof-of-concept study reveals the potential of this label-free joint micro-spectroscopy technique in challenging microbiological issues. In particular, heterogeneous chemo-mechanical maps of Candida biofilms are obtained, without the need for staining or touching the sample. The correlative Raman and Brillouin investigation evidences the role of both extracellular polymeric substances and of hydration water in inducing a marked local softening of the biofilm.
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Affiliation(s)
- S Mattana
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, I-06123 Perugia, Italy.
| | - M Alunni Cardinali
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, I-06123 Perugia, Italy
| | - S Caponi
- IOM-CNR c/o Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, I-06123 Perugia, Italy
| | - D Casagrande Pierantoni
- Department of Pharmaceutical Sciences-Microbiology, University of Perugia, Borgo 20 Giugno 74, 06121 Perugia, Italy
| | - L Corte
- Department of Pharmaceutical Sciences-Microbiology, University of Perugia, Borgo 20 Giugno 74, 06121 Perugia, Italy
| | - L Roscini
- Department of Pharmaceutical Sciences-Microbiology, University of Perugia, Borgo 20 Giugno 74, 06121 Perugia, Italy
| | - G Cardinali
- Department of Pharmaceutical Sciences-Microbiology, University of Perugia, Borgo 20 Giugno 74, 06121 Perugia, Italy; CEMIN, Centre of Excellence on Nanostructured Innovative Materials, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - D Fioretto
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, I-06123 Perugia, Italy; CEMIN, Centre of Excellence on Nanostructured Innovative Materials, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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32
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Pérez-Cota F, Smith RJ, Moradi E, Marques L, Webb KF, Clark M. High resolution 3D imaging of living cells with sub-optical wavelength phonons. Sci Rep 2016; 6:39326. [PMID: 27996028 PMCID: PMC5171858 DOI: 10.1038/srep39326] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/22/2016] [Indexed: 12/11/2022] Open
Abstract
Label-free imaging of living cells below the optical diffraction limit poses great challenges for optical microscopy. Biologically relevant structural information remains below the Rayleigh limit and beyond the reach of conventional microscopes. Super-resolution techniques are typically based on the non-linear and stochastic response of fluorescent labels which can be toxic and interfere with cell function. In this paper we present, for the first time, imaging of live cells using sub-optical wavelength phonons. The axial imaging resolution of our system is determined by the acoustic wavelength (λa = λprobe/2n) and not on the NA of the optics allowing sub-optical wavelength acoustic sectioning of samples using the time of flight. The transverse resolution is currently limited to the optical spot size. The contrast mechanism is significantly determined by the mechanical properties of the cells and requires no additional contrast agent, stain or label to image the cell structure. The ability to breach the optical diffraction limit to image living cells acoustically promises to bring a new suite of imaging technologies to bear in answering exigent questions in cell biology and biomedicine.
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Affiliation(s)
- Fernando Pérez-Cota
- Optics and photonics group, Faculty of Engineering, University of Nottingham,University Park, Nottingham, UK
| | - Richard J. Smith
- Optics and photonics group, Faculty of Engineering, University of Nottingham,University Park, Nottingham, UK
| | - Emilia Moradi
- Optics and photonics group, Faculty of Engineering, University of Nottingham,University Park, Nottingham, UK
| | - Leonel Marques
- Optics and photonics group, Faculty of Engineering, University of Nottingham,University Park, Nottingham, UK
| | - Kevin F. Webb
- Optics and photonics group, Faculty of Engineering, University of Nottingham,University Park, Nottingham, UK
| | - Matt Clark
- Optics and photonics group, Faculty of Engineering, University of Nottingham,University Park, Nottingham, UK
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33
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Edginton RS, Mattana S, Caponi S, Fioretto D, Green E, Winlove CP, Palombo F. Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy. J Vis Exp 2016. [PMID: 27684584 PMCID: PMC5092033 DOI: 10.3791/54648] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Brillouin spectroscopy is an emerging technique in the biomedical field. It probes the mechanical properties of a sample through the interaction of visible light with thermally induced acoustic waves or phonons propagating at a speed of a few km/sec. Information on the elasticity and structure of the material is obtained in a nondestructive contactless manner, hence opening the way to in vivo applications and potential diagnosis of pathology. This work describes the application of Brillouin spectroscopy to the study of biomechanics in elastin and trypsin-digested type I collagen fibers of the extracellular matrix. Fibrous proteins of the extracellular matrix are the building blocks of biological tissues and investigating their mechanical and physical behavior is key to establishing structure-function relationships in normal tissues and the changes which occur in disease. The procedures of sample preparation followed by measurement of Brillouin spectra using a reflective substrate are presented together with details of the optical system and methods of spectral data analysis.
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Affiliation(s)
| | - Sara Mattana
- Department of Physics and Geology, University of Perugia
| | - Silvia Caponi
- Department of Physics and Geology, University of Perugia; Istituto Officina dei Materiali del CNR, Unità di Perugia
| | | | - Ellen Green
- School of Physics and Astronomy, University of Exeter
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34
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Palombo F, Madami M, Fioretto D, Nallala J, Barr H, David A, Stone N. Chemico-mechanical imaging of Barrett's oesophagus. JOURNAL OF BIOPHOTONICS 2016; 9:694-700. [PMID: 27088552 DOI: 10.1002/jbio.201600038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Barrett's oesophagus is a condition characterized by a change in the lining of the oesophagus that markedly increases the risk of adenocarcinoma. We demonstrate the first site-matched application of Brillouin microscopy, Raman microscopy and FTIR micro-spectroscopic imaging to ex-vivo epithelial tissue - Barrett's oesophagus. The mechanical and chemical characters of the epithelium were assessed in histological sections from a patient subjected to endoscopic oesophageal biopsy. Previous studies have shown that both these properties change within the oesophageal wall, owing to the presence of distinct cellular and extracellular constituents which are putatively affected by oesophageal cancer. Brillouin microscopy enables maps of elasticity of the epithelium to be obtained, whilst Raman and FTIR imaging provide 'chemical images' without the need for labelling or staining. This site-matched approach provides a valuable platform for investigating the structure, biomechanics and composition of complex heterogeneous systems. A combined Brillouin-Raman device has potential for in-vivo diagnosis of pathology. First application of site-matched micro Brillouin, Raman and FTIR spectroscopic imaging to epithelial tissue in Barrett's oesophagus.
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Affiliation(s)
| | - Marco Madami
- University of Perugia, Department of Physics and Geology, Perugia, I-06100, Italy
| | - Daniele Fioretto
- University of Perugia, Department of Physics and Geology, Perugia, I-06100, Italy
| | | | - Hugh Barr
- Gloucestershire Royal Hospital, Gloucester, GL1 3NN, UK
| | - Antoine David
- University of Exeter, School of Physics, Exeter, EX4 4QL, UK
- ENSEIRB-MATMECA Telecommunications Department, Bordeaux, F-33402, France
| | - Nick Stone
- University of Exeter, School of Physics, Exeter, EX4 4QL, UK.
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35
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Meng Z, Bustamante Lopez SC, Meissner KE, Yakovlev VV. Subcellular measurements of mechanical and chemical properties using dual Raman-Brillouin microspectroscopy. JOURNAL OF BIOPHOTONICS 2016; 9:201-7. [PMID: 26929086 DOI: 10.1002/jbio.201500163] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 09/01/2015] [Accepted: 09/16/2015] [Indexed: 05/27/2023]
Abstract
Brillouin microspectroscopy is a powerful technique for noninvasive optical imaging. In particular, Brillouin microspectroscopy uniquely allows assessing a sample's mechanical properties with microscopic spatial resolution. Recent advances in background-free Brillouin microspectroscopy make it possible to image scattering samples without substantial degradation of the data quality. However, measurements at the cellular- and subcellular-level have never been performed to date due to the limited signal strength. In this report, by adopting our recently optimized VIPA-based Brillouin spectrometer, we probed the microscopic viscoelasticity of individual red blood cells. These measurements were supplemented by chemically specific measurements using Raman microspectroscopy.
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Affiliation(s)
- Zhaokai Meng
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA.
| | | | - Kenith E Meissner
- College of Engineering, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, United Kingdom
| | - Vladislav V Yakovlev
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
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36
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Palombo F, Winlove CP, Edginton RS, Green E, Stone N, Caponi S, Madami M, Fioretto D. Biomechanics of fibrous proteins of the extracellular matrix studied by Brillouin scattering. J R Soc Interface 2015; 11:20140739. [PMID: 25297313 DOI: 10.1098/rsif.2014.0739] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Brillouin light scattering (BLS) spectroscopy is a technique that is able to detect thermally excited phonons within a material. The speed of propagation of these phonons can be determined from the magnitude of the Brillouin frequency shift between incident and scattered light, thereby providing a measure of the mechanical properties of the material in the gigahertz range. The mechanical properties of the extracellular matrices of biological tissues and their constituent biopolymers are important for normal tissue function and disturbances in these properties are widely implicated in disease. BLS offers the prospect of measuring mechanical properties on a microscopic scale in living tissues, thereby providing insights into structure-function relationships under normal and pathological conditions. In this study, we investigated BLS in collagen and elastin-the fibrous proteins of the extracellular matrix (ECM). Measurements were made on type I collagen in rat tail tendon, type II collagen in articular cartilage and nuchal ligament elastin. The dependence of the BLS spectrum on fibre orientation was investigated in a backscattering geometry using a reflective substrate. Two peaks, a bulk mode arising from phonon propagation along a quasi-radial direction to the fibre axis and a mode parallel to the surface, depending on sample orientation relative to the fibre axis, could be distinguished. The latter peak was fitted to a model of wave propagation through a hexagonally symmetric elastic solid, and the five components of the elasticity tensor were combined to give axial and transverse Young's, shear and bulk moduli of the fibres. These were 10.2, 8.3, 3.2 and 10.9 GPa, and 6.1, 5.3, 1.9 and 8 GPa for dehydrated type I collagen and elastin, respectively. The former values are close to those previously reported. A microfocused BLS approach was also applied providing selection of single fibres. The moduli of collagen and elastin are much higher than those measured at lower frequency using macroscopic strains, and the difference between them is much less. We therefore believe, like previous investigators, that molecular-scale viscoelastic effects are responsible for the frequency dependence of the fibre biomechanics. Combining BLS with larger-scale mechanical testing methods therefore should, in the future, provide a means of following the evolution of mechanical properties in the formation of the complex structures found in the ECM.
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Affiliation(s)
| | | | | | - Ellen Green
- School of Physics, University of Exeter, Exeter EX4 4QL, UK
| | - Nick Stone
- School of Physics, University of Exeter, Exeter EX4 4QL, UK
| | - Silvia Caponi
- Istituto Officina dei Materiali del CNR (CNR-IOM) - Unità di Perugia, c/o Dipartimento di Fisica e Geologia, Perugia I-06100, Italy
| | - Marco Madami
- Dipartimento di Fisica e Geologia, Università di Perugia, Perugia I-06100, Italy
| | - Daniele Fioretto
- Dipartimento di Fisica e Geologia, Università di Perugia, Perugia I-06100, Italy Centro di Eccellenza su Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, Perugia I-06100, Italy
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37
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Pérez-Cota F, Smith RJ, Moradi E, Marques L, Webb KF, Clark M. Thin-film optoacoustic transducers for subcellular Brillouin oscillation imaging of individual biological cells. APPLIED OPTICS 2015; 54:8388-8398. [PMID: 26479614 DOI: 10.1364/ao.54.008388] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
At low frequencies ultrasound is a valuable tool to mechanically characterize and image biological tissues. There is much interest in using high-frequency ultrasound to investigate single cells. Mechanical characterization of vegetal and biological cells by measurement of Brillouin oscillations has been demonstrated using ultrasound in the GHz range. This paper presents a method to extend this technique from the previously reported single-point measurements and line scans into a high-resolution acoustic imaging tool. Our technique uses a three-layered metal-dielectric-metal film as a transducer to launch acoustic waves into the cell we want to study. The design of this transducer and measuring system is optimized to overcome the vulnerability of a cell to the exposure of laser light and heat without sacrificing the signal-to-noise ratio. The transducer substrate shields the cell from the laser radiation, efficiently generates acoustic waves, facilitates optical detection in transmission, and aids with heat dissipation away from the cell. This paper discusses the design of the transducers and instrumentation and presents Brillouin frequency images on phantom, fixed, and living cells.
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38
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Traverso AJ, Thompson JV, Steelman ZA, Meng Z, Scully MO, Yakovlev VV. Dual Raman-Brillouin Microscope for Chemical and Mechanical Characterization and Imaging. Anal Chem 2015. [PMID: 26196847 DOI: 10.1021/acs.analchem.5b02104] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We present a unique confocal microscope capable of measuring the Raman and Brillouin spectra simultaneously from a single spatial location. Raman and Brillouin scattering offer complementary information about a material's chemical and mechanical structure, respectively, and concurrent monitoring of both of these spectra would set a new standard for material characterization. We achieve this by applying recent innovations in Brillouin spectroscopy that reduce the necessary acquisition times to durations comparable to conventional Raman spectroscopy while attaining a high level of spectral accuracy. To demonstrate the potential of the system, we map the Raman and Brillouin spectra of a molded poly(ethylene glycol) diacrylate (PEGDA) hydrogel sample in cyclohexane to create two-dimensional images with high contrast at microscale resolutions. This powerful tool has the potential for very diverse analytical applications in basic science, industry, and medicine.
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Affiliation(s)
| | | | | | | | - Marlan O Scully
- ‡Baylor University, Waco, Texas 76706, United States.,§Princeton University, Princeton, New Jersey 08544, United States
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39
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Battistoni A, Bencivenga F, Fioretto D, Masciovecchio C. Practical way to avoid spurious geometrical contributions in Brillouin light scattering experiments at variable scattering angles. OPTICS LETTERS 2014; 39:5858-5861. [PMID: 25361103 DOI: 10.1364/ol.39.005858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Letter, we present a simple method to avoid the well-known spurious contributions in the Brillouin light scattering (BLS) spectrum arising from the finite aperture of collection optics. The method relies on the use of special spatial filters able to select the scattered light with arbitrary precision around a given value of the momentum transfer (Q). We demonstrate the effectiveness of such filters by analyzing the BLS spectra of a reference sample as a function of scattering angle. This practical and inexpensive method could be an extremely useful tool to fully exploit the potentiality of Brillouin acoustic spectroscopy, as it will easily allow for effective Q-variable experiments with unparalleled luminosity and resolution.
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