1
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Illibauer J, Clodi-Seitz T, Zoufaly A, Aberle JH, Weninger WJ, Foedinger M, Elsayad K. Diagnostic potential of blood plasma longitudinal viscosity measured using Brillouin light scattering. Proc Natl Acad Sci U S A 2024; 121:e2323016121. [PMID: 39088388 DOI: 10.1073/pnas.2323016121] [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: 12/31/2023] [Accepted: 07/01/2024] [Indexed: 08/03/2024] Open
Abstract
Blood plasma viscosity (PV) is an established biomarker for numerous diseases. Measurement of the shear PV using conventional rheological techniques is, however, time consuming and requires significant plasma volumes. Here, we show that Brillouin light scattering (BLS) and angle-resolved spectroscopy measurements of the longitudinal PV from microliter-sized plasma volumes can serve as a proxy for the shear PV measured using conventional viscometers. This is not trivial given the distinct frequency regime probed and the longitudinal viscosity, a combination of the shear and bulk viscosity, representing a unique material property on account of the latter. We demonstrate this for plasma from healthy persons and patients suffering from different severities of COVID-19 (CoV), which has been associated with an increased shear PV. We further show that the additional information contained in the BLS-measured effective longitudinal PV and its temperature scaling can provide unique insight into the chemical constituents and physical properties of plasma that can be of diagnostic value. In particular, we find that changes in the effective longitudinal viscosity are consistent with an increased suspension concentration in CoV patient samples at elevated temperatures that is correlated with disease severity and progression. This is supported by results from rapid BLS spatial-mapping, angle-resolved BLS measurements, changes in the elastic scattering, and anomalies in the temperature scaling of the shear viscosity. Finally, we introduce a compact BLS probe to rapidly perform measurements in plastic transport tubes. Our results open a broad avenue for PV diagnostics based on the high-frequency effective longitudinal PV and show that BLS can provide a means for its implementation.
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Affiliation(s)
- Jennifer Illibauer
- Division of Anatomy, Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria
- Medical Imaging Cluster, Medical University of Vienna, Vienna A-1090, Austria
| | | | - Alexander Zoufaly
- Department of Medicine, Klinik Favoriten, Vienna A-1100, Austria
- Sigmund Freud Private University, Vienna A-1020, Austria
| | - Judith H Aberle
- Center for Virology, Medical University of Vienna, Vienna A-1090, Austria
| | - Wolfgang J Weninger
- Division of Anatomy, Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria
- Medical Imaging Cluster, Medical University of Vienna, Vienna A-1090, Austria
| | - Manuela Foedinger
- Sigmund Freud Private University, Vienna A-1020, Austria
- Institute of Laboratory Diagnostics, Klinik Favoriten, Vienna A-1100, Austria
| | - Kareem Elsayad
- Division of Anatomy, Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria
- Medical Imaging Cluster, Medical University of Vienna, Vienna A-1090, Austria
- Advanced Microscopy, Vienna Biocenter Core Facilities, Vienna A-1030, Austria
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2
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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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3
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Desoutter A, Felbacq D, Gergely C, Varga B, Bonnet L, Etienne P, Vialla R, Cuisinier F, Salehi H, Rousseau E, Rufflé B. Properties of dentin, enamel and their junction, studied with Brillouin scattering and compared to Raman microscopy. Arch Oral Biol 2023; 152:105733. [PMID: 37247560 DOI: 10.1016/j.archoralbio.2023.105733] [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: 02/10/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/31/2023]
Abstract
OBJECTIVE Dentin, enamel and the transition zone, called the dentin-enamel junction (DEJ), have an organization and properties that play a critical role in tooth resilience and in stopping the propagation of cracks. Understanding their chemical and micro-biomechanical properties is then of foremost importance. The aim of this study is to apply Brillouin microscopy on a complex biological structure, that is, the DEJ, and to compare these results with those obtained with Raman microscopy. DESIGN Both techniques allow noncontact measurements at the microscopic scale. Brillouin microscopy is based on the interaction between acoustic phonons and laser photons and gives a relation between the frequency shift of the scattered light and the stiffness of the sample. Raman spectra contain peaks related to specific chemical bonds. RESULTS Comparison of the Brillouin and Raman cartographies reveals correlations between mechanical and chemical properties. Indeed, the shapes of the phosphate content and stiffness curves are similar. The two spectroscopies give compatible values for the mean distance between two tubules, i.e., 4-6 µm. Moreover, for the first time, the daily cross striations of enamel could be studied, indicating a relationship between the variation in the phosphate concentration and the variation in the rigidity within the enamel prisms. CONCLUSIONS We demonstrate here the possibility of using Brillouin scattering microscopy to both study complex biological materials such as the enamel-dentin junction and visualize secondary structures. Correlations between the chemical composition and mechanical properties could help in better understanding the tissue histology.
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Affiliation(s)
- Alban Desoutter
- LBN, Univ. Montpellier, 545 avenue Professeur Jean-Louis Viala, 34193 Montpellier Cedex 5, France.
| | - Didier Felbacq
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Csilla Gergely
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Béla Varga
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Laurent Bonnet
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Pascal Etienne
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Remy Vialla
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Frédéric Cuisinier
- LBN, Univ. Montpellier, 545 avenue Professeur Jean-Louis Viala, 34193 Montpellier Cedex 5, France
| | - Hamideh Salehi
- LBN, Univ. Montpellier, 545 avenue Professeur Jean-Louis Viala, 34193 Montpellier Cedex 5, France
| | - Emmanuel Rousseau
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
| | - Benoit Rufflé
- L2C, Univ. Montpellier, CNRS, place Eugène Bataillon, 34090 Montpellier, France
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4
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Windberger U, Sparer A, Elsayad K. The role of plasma in the yield stress of blood. Clin Hemorheol Microcirc 2023; 84:369-383. [PMID: 37334582 DOI: 10.3233/ch-231701] [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] [Indexed: 06/20/2023]
Abstract
BACKGROUND Yielding and shear elasticity of blood are merely discussed within the context of hematocrit and erythrocyte aggregation. However, plasma might play a substantial role due its own viscoelasticity. OBJECTIVE If only erythrocyte aggregation and hematocrit would determine yielding, blood of different species with comparable values would present comparable yield stresses. METHODS rheometry (SAOS: amplitude and frequency sweep tests; flow curves) of hematocrit-matched samples at 37°C. Brillouin Light Scattering Spectroscopy at 38°C. RESULTS Yield stress for pig: 20mPa, rat: 18mPa, and human blood: 9mPa. Cow and sheep blood were not in quasi-stationary state supporting the role of erythrocyte aggregation for the development of elasticity and yielding. However, pig and human erythrocytes feature similar aggregability, but yield stress of porcine blood was double. Murine and ruminant erythrocytes both rarely aggregate, but their blood behavior was fundamentally different. Pig plasma was shear-thinning and murine plasma was platelet-enriched, supporting the role of plasma for triggering collective effects and gel-like properties. CONCLUSIONS Blood behavior near zero shear flow is not based solely on erythrocyte aggregation and hematocrit, but includes the hydrodynamic interaction with plasma. The shear stress required to break down elasticity is not the critical shear stress for dispersing erythrocyte aggregates, but the shear stress required to fracture the entire assembly of blood cells within their intimate embedding.
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Affiliation(s)
- U Windberger
- Core Facility Laboratory Animal Breeding and Husbandry, Decentralized Biomedical Facilities, Medical University Vienna, Austria
| | - A Sparer
- Core Facility Laboratory Animal Breeding and Husbandry, Decentralized Biomedical Facilities, Medical University Vienna, Austria
| | - K Elsayad
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University Vienna, Austria
- Medical Imaging Cluster (MIC), Medical University of Vienna, Austria
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5
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Ng RC, El Sachat A, Cespedes F, Poblet M, Madiot G, Jaramillo-Fernandez J, Florez O, Xiao P, Sledzinska M, Sotomayor-Torres CM, Chavez-Angel E. Excitation and detection of acoustic phonons in nanoscale systems. NANOSCALE 2022; 14:13428-13451. [PMID: 36082529 PMCID: PMC9520674 DOI: 10.1039/d2nr04100f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Phonons play a key role in the physical properties of materials, and have long been a topic of study in physics. While the effects of phonons had historically been considered to be a hindrance, modern research has shown that phonons can be exploited due to their ability to couple to other excitations and consequently affect the thermal, dielectric, and electronic properties of solid state systems, greatly motivating the engineering of phononic structures. Advances in nanofabrication have allowed for structuring and phonon confinement even down to the nanoscale, drastically changing material properties. Despite developments in fabricating such nanoscale devices, the proper manipulation and characterization of phonons continues to be challenging. However, a fundamental understanding of these processes could enable the realization of key applications in diverse fields such as topological phononics, information technologies, sensing, and quantum electrodynamics, especially when integrated with existing electronic and photonic devices. Here, we highlight seven of the available methods for the excitation and detection of acoustic phonons and vibrations in solid materials, as well as advantages, disadvantages, and additional considerations related to their application. We then provide perspectives towards open challenges in nanophononics and how the additional understanding granted by these techniques could serve to enable the next generation of phononic technological applications.
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Affiliation(s)
- Ryan C Ng
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | | | - Francisco Cespedes
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
- Departamento de Física, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Martin Poblet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Guilhem Madiot
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Juliana Jaramillo-Fernandez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Omar Florez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
- Departamento de Física, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Peng Xiao
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
- Departamento de Física, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Marianna Sledzinska
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Clivia M Sotomayor-Torres
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
- ICREA, Passeig Lluis Companys 23, 08010 Barcelona, Spain
| | - Emigdio Chavez-Angel
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
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6
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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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7
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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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8
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Fiore A, Scarcelli G. Multipass etalon cascade for high-resolution parallel spectroscopy. OPTICS LETTERS 2021; 46:781-784. [PMID: 33577513 PMCID: PMC8607433 DOI: 10.1364/ol.418090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
Spectral contrast, the ability to measure frequency components of vastly different intensity, is critical in optical spectroscopy. For high spectral contrast at high spectral resolution, scanning etalons are generally used, as they allow cascading multiple dispersive elements. However, scanning instruments are inherently limited in terms of acquisition speed. Here we report a single-shot cascaded spectrometer design, in which light is dispersed along a single dispersion direction at every stage and thus can be recirculated in the same etalon multiple times. Using this design principle, we demonstrate single-shot spectral measurements at sub-gigahertz resolution and unprecedented spectral contrast (∼80dB).
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Affiliation(s)
- Antonio Fiore
- Fischell Department of Bioengineering, University of Maryland —8278 Paint Branch Drive, College Park, MD 20742, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland —8278 Paint Branch Drive, College Park, MD 20742, USA
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9
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Zhang J, Scarcelli G. Mapping mechanical properties of biological materials via an add-on Brillouin module to confocal microscopes. Nat Protoc 2021; 16:1251-1275. [PMID: 33452504 PMCID: PMC8218248 DOI: 10.1038/s41596-020-00457-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/04/2020] [Indexed: 01/29/2023]
Abstract
Several techniques have been developed over the past few decades to assess the mechanical properties of biological samples, which has fueled a rapid growth in the fields of biophysics, bioengineering, and mechanobiology. In this context, Brillouin optical spectroscopy has long been known as an intriguing modality for noncontact material characterization. However, limited by speed and sample damage, it had not translated into a viable imaging modality for biomedically relevant materials. Recently, based on a novel spectroscopy strategy that substantially improves the speed of Brillouin measurement, confocal Brillouin microscopy has emerged as a unique complementary tool to traditional methods as it allows noncontact, nonperturbative, label-free measurements of material mechanical properties. The feasibility and potential of this innovative technique at both the cell and tissue level have been extensively demonstrated over the past decade. As Brillouin technology is rapidly recognized, a standard approach for building and operating Brillouin microscopes is required to facilitate the widespread adoption of this technology. In this protocol, we aim to establish a robust approach for instrumentation, and data acquisition and analysis. By carefully following this protocol, we expect that a Brillouin instrument can be built in 5-9 days by a person with basic optics knowledge and alignment experience; the data acquisition as well as postprocessing can be accomplished within 2-8 h.
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Affiliation(s)
- Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.
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10
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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: 168] [Impact Index Per Article: 33.6] [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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11
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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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12
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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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13
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Nikolić M, Scarcelli G. Long-term Brillouin imaging of live cells with reduced absorption-mediated damage at 660 nm wavelength. BIOMEDICAL OPTICS EXPRESS 2019; 10:1567-1580. [PMID: 31086695 PMCID: PMC6484981 DOI: 10.1364/boe.10.001567] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 05/18/2023]
Abstract
In Brillouin microscopy, absorption-induced photodamage of incident light is the primary limitation on signal-to-noise ratio in many practical scenarios. Here we show that 660 nm may represent an optimal wavelength for Brillouin microscopy as it offers minimal absorption-mediated photodamage at high Brillouin scattering efficiency and the possibility to use a pure and narrow laser line from solid-state lasing medium. We demonstrate that live cells are ~80 times less susceptible to the 660 nm incident light compared to 532 nm light, which overall allows Brillouin imaging of up to more than 30 times higher SNR. We show that this improvement enables Brillouin imaging of live biological samples with improved accuracy, higher speed and/or larger fields of views with denser sampling.
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Affiliation(s)
- Miloš Nikolić
- Maryland Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - Giuliano Scarcelli
- Maryland Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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14
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Fiore A, Bevilacqua C, Scarcelli G. Direct Three-Dimensional Measurement of Refractive Index via Dual Photon-Phonon Scattering. PHYSICAL REVIEW LETTERS 2019; 122:103901. [PMID: 30932682 PMCID: PMC6530466 DOI: 10.1103/physrevlett.122.103901] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Indexed: 05/06/2023]
Abstract
We developed a microscopy technique that can measure the local refractive index without sampling the optical phase delay of the electromagnetic radiation. To do this, we designed and experimentally demonstrated a setup with two colocalized Brillouin scattering interactions that couple to a common acoustic phonon axis; in this scenario, the ratio of Brillouin frequency shifts depends on the refractive index, but not on any other mechanical and/or optical properties of the sample. Integrating the spectral measurement within a confocal microscope, the refractive index is mapped at micron-scale three-dimensional resolution. As the refractive index is probed in epidetection and without assumptions on the geometrical dimensions of the sample, this method may prove useful to characterize biological cells and tissues.
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Affiliation(s)
- Antonio Fiore
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Carlo Bevilacqua
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari, I-70126 Bari, Italy
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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Bevilacqua C, Sánchez-Iranzo H, Richter D, Diz-Muñoz A, Prevedel R. Imaging mechanical properties of sub-micron ECM in live zebrafish using Brillouin microscopy. BIOMEDICAL OPTICS EXPRESS 2019; 10:1420-1431. [PMID: 30891356 PMCID: PMC6420298 DOI: 10.1364/boe.10.001420] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 05/20/2023]
Abstract
In this work, we quantify the mechanical properties of the extra-cellular matrix (ECM) in live zebrafish using Brillouin microscopy. Optimization of the imaging conditions and parameters, combined with careful spectral analysis, allows us to resolve the thin ECM and distinguish its Brillouin frequency shift, a proxy for mechanical properties, from the surrounding tissue. High-resolution mechanical mapping further enables the direct measurement of the thickness of the ECM label-free and in-vivo. We find the ECM to be ~500 nm thick, and in very good agreement with electron microscopy quantification. Our results open the door for future studies that aim to investigate the role of ECM mechanics for zebrafish morphogenesis and axis elongation.
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Affiliation(s)
- Carlo Bevilacqua
- 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
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
- These authors contributed equally
| | - Héctor Sánchez-Iranzo
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- These authors contributed equally
| | - Dmitry Richter
- 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
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics 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
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Fiore A, Scarcelli G. Single etalon design for two-stage cross-axis VIPA spectroscopy. BIOMEDICAL OPTICS EXPRESS 2019; 10:1475-1481. [PMID: 30891361 PMCID: PMC6420281 DOI: 10.1364/boe.10.001475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 05/15/2023]
Abstract
Two-stage cross axis VIPA spectrometers have been widely used in Brillouin microscopy since they provide single shot spectral measurements at high throughput and extinction. However, this spectrometer configuration presents challenges such as size, cost and alignment difficulties between the two cascaded etalons. Here, we present a cross-axis VIPA spectrometer that implements a single etalon, using a light recirculation architecture to achieve the multistage configuration.
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Affiliation(s)
- Antonio Fiore
- Fischell Department of Bioengineering, University of Maryland, 8278 Paint Branch Drive, College Park, MD 20742, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, 8278 Paint Branch Drive, College Park, MD 20742, USA
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Noninvasive Imaging: Brillouin Confocal Microscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1092:351-364. [DOI: 10.1007/978-3-319-95294-9_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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Zhang J, Raghunathan R, Rippy J, Wu C, Finnell RH, Larin KV, Scarcelli G. Tissue biomechanics during cranial neural tube closure measured by Brillouin microscopy and optical coherence tomography. Birth Defects Res 2018; 111:991-998. [PMID: 30239173 DOI: 10.1002/bdr2.1389] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/03/2018] [Accepted: 08/02/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Embryonic development involves the interplay of driving forces that shape the tissue and the mechanical resistance that the tissue offers in response. While increasing evidence has suggested the crucial role of physical mechanisms underlying embryo development, tissue biomechanics is not well understood because of the lack of techniques that can quantify the stiffness of tissue in situ with 3D high-resolution and in a noncontact manner. METHODS We used two all-optical techniques, optical coherence tomography (OCT) and Brillouin microscopy, to map the longitudinal modulus of the tissue from mouse embryos in situ. RESULTS We acquired 2D mechanical maps of the neural tube region of embryos at embryonic day (E) 8.5 (n = 2) and E9.5 (n = 2) with submicron spatial resolution. We found the modulus of tissue varied distinctly within the neural tube region of the same embryo and between embryos at different development stages, suggesting our technique has enough sensitivity and spatial resolution to monitor the tissue mechanics during embryonic development in a noncontact and noninvasive manner. CONCLUSIONS We demonstrated the capability of OCT-guided Brillouin microscopy to quantify tissue longitudinal modulus of mouse embryos in situ, and observed distinct change in the modulus during the closure of cranial neural tube. Although this preliminary work cannot provide definitive conclusions on biomechanics of neural tube closure yet as a result of the limited number of samples, it provides an approach of quantifying the tissue mechanics during embryo development in situ, thus could be helpful in investigating the role of tissue biomechanics in the regulation of embryonic development. Our next study involving more embryo samples will investigate systematic changes in tissue mechanics during embryonic development.
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Affiliation(s)
- Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, Maryland
| | - Raksha Raghunathan
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Justin Rippy
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Chen Wu
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Richard H Finnell
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas
| | - Kirill V Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas.,Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas.,Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
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β-Catenin-dependent mechanotransduction dates back to the common ancestor of Cnidaria and Bilateria. Proc Natl Acad Sci U S A 2018; 115:6231-6236. [PMID: 29784822 PMCID: PMC6004442 DOI: 10.1073/pnas.1713682115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Besides genetic regulation, mechanical forces have been identified as important cues in numerous developmental processes. Mechanical forces can activate biochemical cascades in a process called mechanotransduction. Recent studies in vertebrates and flies elucidated the role of mechanical forces for mesodermal gene expression. However, it remains unclear whether mechanotransduction is a universal regulatory mechanism throughout Metazoa. Here, we show in the sea anemone Nematostella vectensis that mechanical pressure can ectopically activate or restore brachyury expression. This mechanotransduction is dependent on β-catenin, similar to vertebrates. We propose that a regulatory feedback loop between genetic and mechanical gene activation exists during gastrulation and the β-catenin–dependent mechanotransduction is an ancient regulatory mechanism, which was present in the common ancestor of cnidarians and bilaterians. Although the genetic regulation of cellular differentiation processes is well established, recent studies have revealed the role of mechanotransduction on a variety of biological processes, including regulation of gene expression. However, it remains unclear how universal and widespread mechanotransduction is in embryonic development of animals. Here, we investigate mechanosensitive gene expression during gastrulation of the starlet sea anemone Nematostella vectensis, a cnidarian model organism. We show that the blastoporal marker gene brachyury is down-regulated by blocking myosin II-dependent gastrulation movements. Brachyury expression can be restored by applying external mechanical force. Using CRISPR/Cas9 and morpholino antisense technology, we also show that mechanotransduction leading to brachyury expression is β-catenin dependent, similar to recent findings in fish and Drosophila [Brunet T, et al. (2013) Nat Commun 4:1–15]. Finally, we demonstrate that prolonged application of mechanical stress on the embryo leads to ectopic brachyury expression. Thus, our data indicate that β-catenin–dependent mechanotransduction is an ancient gene regulatory mechanism, which was present in the common ancestor of cnidarians and bilaterians, at least 600 million years ago.
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Edrei E, Scarcelli G. Brillouin micro-spectroscopy through aberrations via sensorless adaptive optics. APPLIED PHYSICS LETTERS 2018; 112:163701. [PMID: 29713091 PMCID: PMC5902333 DOI: 10.1063/1.5027838] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 03/30/2018] [Indexed: 05/04/2023]
Abstract
Brillouin spectroscopy is a powerful optical technique for non-contact viscoelastic characterizations which has recently found applications in three-dimensional mapping of biological samples. Brillouin spectroscopy performances are rapidly degraded by optical aberrations and have therefore been limited to homogenous transparent samples. In this work, we developed an adaptive optics (AO) configuration designed for Brillouin scattering spectroscopy to engineer the incident wavefront and correct for aberrations. Our configuration does not require direct wavefront sensing and the injection of a "guide-star"; hence, it can be implemented without the need for sample pre-treatment. We used our AO-Brillouin spectrometer in aberrated phantoms and biological samples and obtained improved precision and resolution of Brillouin spectral analysis; we demonstrated 2.5-fold enhancement in Brillouin signal strength and 1.4-fold improvement in axial resolution because of the correction of optical aberrations.
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Affiliation(s)
- Eitan Edrei
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
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