1
|
Gorman BR, McNeil LE. Effect of polymerization on free water in polyacrylamide hydrogels observed with Brillouin spectroscopy. SOFT MATTER 2024; 20:5164-5173. [PMID: 38895797 DOI: 10.1039/d4sm00250d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Brillouin spectroscopy is used to determine the effects of polymer concentration, crosslinking density, and polymerization on the longitudinal storage and loss moduli of polyacrylamide hydrogels. The model established by Chiarelli et al. is implemented to calculate the speed of sound in the free water [Chiarelli et al., The Journal of the Acoustical Society of America, 2010, 127(3), 1197-1207]. The polymer concentration has the greatest effect on the moduli of the polymer matrix. We determined that the crosslink density has no measurable effect on the logitudinal storage or loss modulus of polyacrylamide hydrogels when measurements are made at GHz frequencies, in contrast to measurements made at kHz frequencies as documented by other studies. However, the moduli are independent of monomer concentration if the acrylamide is not polymerized. We show at the GHz frequency that the incorporation of acrylamide polymer chains affects the mechanical properties of the free water. The speed of sound in the free water is reduced by the introduction of polymerized acrylamide. The long polymer chains and their interactions with the bounded water disrupt the bonding organization of the unbound water, causing a reduction of the average hydrogen bond strength between free water molecules. This results in a decreased speed of sound in the free water and an increase in the longitudinal storage modulus of the hydrogel.
Collapse
Affiliation(s)
- Britta R Gorman
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
| | - L E McNeil
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
| |
Collapse
|
2
|
Bilenca A, Prevedel R, Scarcelli G. Current state of stimulated Brillouin scattering microscopy for the life sciences. JPHYS PHOTONICS 2024; 6:032001. [PMID: 38939757 PMCID: PMC11200595 DOI: 10.1088/2515-7647/ad5506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/21/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024] Open
Abstract
Stimulated Brillouin scattering (SBS) microscopy is a nonlinear all-optical imaging method that provides mechanical contrast based on the interaction of laser radiation and acoustical vibrational modes. Featuring high mechanical specificity and sensitivity, three-dimensional sectioning, and practical imaging times, SBS microscopy with (quasi) continuous wave excitation is rapidly advancing as a promising imaging tool for label-free visualization of viscoelastic information of materials and living biological systems. In this article, we introduce the theory of SBS microscopy and review the current state-of-the-art as well as recent innovations, including different approaches to system designs and data analysis. In particular, various performance parameters of SBS microscopy and its applications in the life sciences are described and discussed. Future perspectives for SBS microscopy are also presented.
Collapse
Affiliation(s)
- Alberto Bilenca
- Biomedical Engineering Department, Ben-Gurion University of the Negev, 1 Ben Gurion Blvd, Be’er-Sheva 84105, Israel
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, 1 Ben Gurion Blvd, Be’er-Sheva 84105, Israel
| | - Robert Prevedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Coker ZN, Troyanova-Wood M, Steelman ZA, Ibey BL, Bixler JN, Scully MO, Yakovlev VV. Brillouin microscopy monitors rapid responses in subcellular compartments. PHOTONIX 2024; 5:9. [PMID: 38618142 PMCID: PMC11006764 DOI: 10.1186/s43074-024-00123-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 02/12/2024] [Accepted: 03/11/2024] [Indexed: 04/16/2024]
Abstract
Measurements and imaging of the mechanical response of biological cells are critical for understanding the mechanisms of many diseases, and for fundamental studies of energy, signal and force transduction. The recent emergence of Brillouin microscopy as a powerful non-contact, label-free way to non-invasively and non-destructively assess local viscoelastic properties provides an opportunity to expand the scope of biomechanical research to the sub-cellular level. Brillouin spectroscopy has recently been validated through static measurements of cell viscoelastic properties, however, fast (sub-second) measurements of sub-cellular cytomechanical changes have yet to be reported. In this report, we utilize a custom multimodal spectroscopy system to monitor for the very first time the rapid viscoelastic response of cells and subcellular structures to a short-duration electrical impulse. The cytomechanical response of three subcellular structures - cytoplasm, nucleoplasm, and nucleoli - were monitored, showing distinct mechanical changes despite an identical stimulus. Through this pioneering transformative study, we demonstrate the capability of Brillouin spectroscopy to measure rapid, real-time biomechanical changes within distinct subcellular compartments. Our results support the promising future of Brillouin spectroscopy within the broad scope of cellular biomechanics.
Collapse
Affiliation(s)
- Zachary N. Coker
- Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843 USA
- SAIC, Fort Sam Houston, TX 78234 USA
| | | | - Zachary A. Steelman
- Air Force Research Laboratory, JBSA Fort Sam Houston, Fort Sam Houston, TX 78234 USA
| | - Bennett L. Ibey
- Air Force Research Laboratory, JBSA Fort Sam Houston, Fort Sam Houston, TX 78234 USA
| | - Joel N. Bixler
- Air Force Research Laboratory, JBSA Fort Sam Houston, Fort Sam Houston, TX 78234 USA
| | - Marlan O. Scully
- Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843 USA
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843 USA
| | - Vladislav V. Yakovlev
- Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843 USA
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843 USA
- Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, 101 Bizzell Street, College Station, TX 77843 USA
| |
Collapse
|
5
|
Rodríguez-López R, Wang Z, Oda H, Erdi M, Kofinas P, Fytas G, Scarcelli G. Network Viscoelasticity from Brillouin Spectroscopy. Biomacromolecules 2024; 25:955-963. [PMID: 38156622 PMCID: PMC10865340 DOI: 10.1021/acs.biomac.3c01073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/02/2023] [Accepted: 12/04/2023] [Indexed: 01/03/2024]
Abstract
Even though the physical nature of shear and longitudinal moduli are different, empirical correlations between them have been reported in several biological systems. This correlation is of fundamental interest and immense practical value in biomedicine due to the importance of the shear modulus and the possibility to map the longitudinal modulus at high-resolution with all-optical spectroscopy. We investigate the origin of such a correlation in hydrogels. We hypothesize that both moduli are influenced in the same direction by underlying physicochemical properties, which leads to the observed material-dependent correlation. Matching theoretical models with experimental data, we quantify the scenarios in which the correlation holds. For polymerized hydrogels, a correlation was found across different hydrogels through a common dependence on the effective polymer volume fraction. For hydrogels swollen to equilibrium, the correlation is valid only within a given hydrogel system, as the moduli are found to have different scalings on the swelling ratio. The observed correlation allows one to extract one modulus from another in relevant scenarios.
Collapse
Affiliation(s)
- Raymundo Rodríguez-López
- Fischell
Department of Bioengineering, University
of Maryland, College
Park, Maryland 20742, United States
| | - Zuyuan Wang
- School
of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, China
| | - Haruka Oda
- School
of Information Science and Technology, The
University of Tokyo, Tokyo 113-8656,Japan
| | - Metecan Erdi
- Department
of Chemical and Biomolecular Engineering, University of Maryland, College
Park, Maryland 20742, United States
| | - Peter Kofinas
- Department
of Chemical and Biomolecular Engineering, University of Maryland, College
Park, Maryland 20742, United States
| | - George Fytas
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Institute
of Electronic Structure and Laser, FO.R.T.H, N. Plastira 10, Heraklion, 70013, Greece
| | - Giuliano Scarcelli
- Fischell
Department of Bioengineering, University
of Maryland, College
Park, Maryland 20742, United States
| |
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Shi C, Zhang H, Zhang J. Non-contact and label-free biomechanical imaging: Stimulated Brillouin microscopy and beyond. FRONTIERS IN PHYSICS 2023; 11:1175653. [PMID: 37377499 PMCID: PMC10299794 DOI: 10.3389/fphy.2023.1175653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Brillouin microscopy based on spontaneous Brillouin scattering has emerged as a unique elastography technique because of its merit of non-contact, label-free, and high-resolution mechanical imaging of biological cell and tissue. Recently, several new optical modalities based on stimulated Brillouin scattering have been developed for biomechanical research. As the scattering efficiency of the stimulated process is much higher than its counterpart in the spontaneous process, stimulated Brillouin-based methods have the potential to significantly improve the speed and spectral resolution of existing Brillouin microscopy. Here, we review the ongoing technological advancements of three methods, including continuous wave stimulated Brillouin microscopy, impulsive stimulated Brillouin microscopy, and laser-induced picosecond ultrasonics. We describe the physical principle, the representative instrumentation, and biological application of each method. We further discuss the current limitations as well as the challenges for translating these methods into a visible biomedical instrument for biophysics and mechanobiology.
Collapse
Affiliation(s)
- Chenjun Shi
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, United States
| | - Hongyuan Zhang
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Jitao Zhang
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, United States
| |
Collapse
|
9
|
Leartprapun N, Adie SG. Recent advances in optical elastography and emerging opportunities in the basic sciences and translational medicine [Invited]. BIOMEDICAL OPTICS EXPRESS 2023; 14:208-248. [PMID: 36698669 PMCID: PMC9842001 DOI: 10.1364/boe.468932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 05/28/2023]
Abstract
Optical elastography offers a rich body of imaging capabilities that can serve as a bridge between organ-level medical elastography and single-molecule biophysics. We review the methodologies and recent developments in optical coherence elastography, Brillouin microscopy, optical microrheology, and photoacoustic elastography. With an outlook toward maximizing the basic science and translational clinical impact of optical elastography technologies, we discuss potential ways that these techniques can integrate not only with each other, but also with supporting technologies and capabilities in other biomedical fields. By embracing cross-modality and cross-disciplinary interactions with these parallel fields, optical elastography can greatly increase its potential to drive new discoveries in the biomedical sciences as well as the development of novel biomechanics-based clinical diagnostics and therapeutics.
Collapse
Affiliation(s)
- Nichaluk Leartprapun
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, USA
- Present affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Steven G. Adie
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, USA
| |
Collapse
|
10
|
In Vivo Evaluation of the Effects of SMILE with Different Amounts of Stromal Ablation on Corneal Biomechanics by Optical Coherence Elastography. Diagnostics (Basel) 2022; 13:diagnostics13010030. [PMID: 36611322 PMCID: PMC9818797 DOI: 10.3390/diagnostics13010030] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/18/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
This work aims to depth-resolved quantitatively analyze the effect of different stromal ablation amounts on the corneal biomechanical properties during small incision lenticule extraction (SMILE) using optical coherence elastography (OCE). A 4.5-MHz ultrasonic transducer was used to excite elastic waves in the corneal tissue. The OCE system combined with the antisymmetric Lamb wave model was employed to achieve a high-resolution, high-sensitivity, and depth-resolved quantitative detection of the corneal Young's modulus. Eighteen rabbits were randomly divided into three groups; each group had six rabbits. The first and second groups underwent -3D and -6D SMILE surgeries, and the third group was the control group, respectively. Young's modulus of the corneal cap and residual stromal bed (RSB) were both increased after SMILE, which shared the stress under intraocular pressure (IOP). Furthermore, the Young's modulus of both the corneal cap and RSB after 3D SMILE group were significantly lower than that in the -6D group, which indicated that the increases in the post-operative corneal Young's modulus were positively correlated with the amount of stromal ablation. The OCE system for quantitative spatial characterization of corneal biomechanical properties can provide useful information on the extent of safe ablation for SMILE procedures.
Collapse
|
11
|
Mirecki B, Rogalski M, Arcab P, Rogujski P, Stanaszek L, Józwik M, Trusiak M. Low-intensity illumination for lensless digital holographic microscopy with minimized sample interaction. BIOMEDICAL OPTICS EXPRESS 2022; 13:5667-5682. [PMID: 36733749 PMCID: PMC9872902 DOI: 10.1364/boe.464367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 06/18/2023]
Abstract
Exposure to laser light alters cell culture examination via optical microscopic imaging techniques based on label-free coherent digital holography. To mitigate this detrimental feature, researchers tend to use a broader spectrum and lower intensity of illumination, which can decrease the quality of holographic imaging due to lower resolution and higher noise. We study the lensless digital holographic microscopy (LDHM) ability to operate in the low photon budget (LPB) regime to enable imaging of unimpaired live cells with minimized sample interaction. Low-cost off-the-shelf components are used, promoting the usability of such a straightforward approach. We show that recording data in the LPB regime (down to 7 µW of illumination power) does not limit the contrast or resolution of the hologram phase and amplitude reconstruction compared to regular illumination. The LPB generates hardware camera shot noise, however, to be effectively minimized via numerical denoising. The ability to obtain high-quality, high-resolution optical complex field reconstruction was confirmed using the USAF 1951 amplitude sample, phase resolution test target, and finally, live glial restricted progenitor cells (as a challenging strongly absorbing and scattering biomedical sample). The proposed approach based on severely limiting the photon budget in lensless holographic microscopy method can open new avenues in high-throughout (optimal resolution, large field-of-view, and high signal-to-noise-ratio single-hologram reconstruction) cell culture imaging with minimized sample interaction.
Collapse
Affiliation(s)
- Bartosz Mirecki
- Warsaw University of Technology, Institute of Micromechanics and Photonics, 8 Sw. A. Boboli St., 02-525 Warsaw, Poland
- Authors contributed equally to this work
| | - Mikołaj Rogalski
- Warsaw University of Technology, Institute of Micromechanics and Photonics, 8 Sw. A. Boboli St., 02-525 Warsaw, Poland
- Authors contributed equally to this work
| | - Piotr Arcab
- Warsaw University of Technology, Institute of Micromechanics and Photonics, 8 Sw. A. Boboli St., 02-525 Warsaw, Poland
- Authors contributed equally to this work
| | - Piotr Rogujski
- NeuroRepair Department, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Adolfa Pawinskiego St., 02-106 Warsaw, Poland
| | - Luiza Stanaszek
- NeuroRepair Department, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Adolfa Pawinskiego St., 02-106 Warsaw, Poland
| | - Michał Józwik
- Warsaw University of Technology, Institute of Micromechanics and Photonics, 8 Sw. A. Boboli St., 02-525 Warsaw, Poland
| | - Maciej Trusiak
- Warsaw University of Technology, Institute of Micromechanics and Photonics, 8 Sw. A. Boboli St., 02-525 Warsaw, Poland
| |
Collapse
|
12
|
Comprehensive single-shot biophysical cytometry using simultaneous quantitative phase imaging and Brillouin spectroscopy. Sci Rep 2022; 12:18285. [PMID: 36316372 PMCID: PMC9622723 DOI: 10.1038/s41598-022-23049-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Single-cell analysis, or cytometry, is a ubiquitous tool in the biomedical sciences. Whereas most cytometers use fluorescent probes to ascertain the presence or absence of targeted molecules, biophysical parameters such as the cell density, refractive index, and viscosity are difficult to obtain. In this work, we combine two complementary techniques-quantitative phase imaging and Brillouin spectroscopy-into a label-free image cytometry platform capable of measuring more than a dozen biophysical properties of individual cells simultaneously. Using a geometric simplification linked to freshly plated cells, we can acquire the cellular diameter, volume, refractive index, mass density, non-aqueous mass, fluid volume, dry volume, the fractional water content of cells, both by mass and by volume, the Brillouin shift, Brillouin linewidth, longitudinal modulus, longitudinal viscosity, the loss modulus, and the loss tangent, all from a single acquisition, and with no assumptions of underlying parameters. Our methods are validated across three cell populations, including a control population of CHO-K1 cells, cells exposed to tubulin-disrupting nocodazole, and cells under hypoosmotic shock. Our system will unlock new avenues of research in biophysics, cell biology, and medicine.
Collapse
|
13
|
Nikolić M, Scarcelli G, Tanner K. Multimodal microscale mechanical mapping of cancer cells in complex microenvironments. Biophys J 2022; 121:3586-3599. [PMID: 36059196 PMCID: PMC9617162 DOI: 10.1016/j.bpj.2022.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/05/2022] [Accepted: 09/02/2022] [Indexed: 02/07/2023] Open
Abstract
The mechanical phenotype of the cell is critical for survival following deformations due to confinement and fluid flow. One idea is that cancer cells are plastic and adopt different mechanical phenotypes under different geometries that aid in their survival. Thus, an attractive goal is to disrupt cancer cells' ability to adopt multiple mechanical states. To begin to address this question, we aimed to quantify the diversity of these mechanical states using in vitro biomimetics to mimic in vivo two-dimensional (2D) and 3D extracellular matrix environments. Here, we used two modalities Brillouin microscopy (∼GHz) and broadband frequency (7-15 kHz) optical tweezer microrheology to measure microscale cell mechanics. We measured the response of intracellular mechanics of cancer cells cultured in 2D and 3D environments where we modified substrate stiffness, dimensionality (2D versus 3D), and presence of fibrillar topography. We determined that there was good agreement between two modalities despite the difference in timescale of the two measurements. These findings on cell mechanical phenotype in different environments confirm a correlation between modalities that employ different mechanisms at different temporal scales (Hz-kHz versus GHz). We also determined that observed heterogeneity in cell shape is more closely linked to the cells' mechanical state. Moreover, individual cells in multicellular spheroids exhibit a lower degree of mechanical heterogeneity when compared with single cells cultured in monodisperse 3D cultures. The observed decreased heterogeneity among cells in spheroids suggested that there is mechanical cooperativity between cells that make up a single spheroid.
Collapse
Affiliation(s)
- Miloš Nikolić
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; Maryland Biophysics Program, IPST, University of Maryland, College Park, Maryland
| | - Giuliano Scarcelli
- Maryland Biophysics Program, IPST, University of Maryland, College Park, Maryland; Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Kandice Tanner
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
| |
Collapse
|
14
|
Pahapale GJ, Tao J, Nikolic M, Gao S, Scarcelli G, Sun SX, Romer LH, Gracias DH. Directing Multicellular Organization by Varying the Aspect Ratio of Soft Hydrogel Microwells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104649. [PMID: 35434926 PMCID: PMC9189654 DOI: 10.1002/advs.202104649] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 03/08/2022] [Indexed: 06/03/2023]
Abstract
Multicellular organization with precise spatial definition is essential to various biological processes, including morphogenesis, development, and healing in vascular and other tissues. Gradients and patterns of chemoattractants are well-described guides of multicellular organization, but the influences of 3D geometry of soft hydrogels are less well defined. Here, the discovery of a new mode of endothelial cell self-organization guided by combinatorial effects of stiffness and geometry, independent of protein or chemical patterning, is described. Endothelial cells in 2 kPa microwells are found to be ≈30 times more likely to migrate to the edge to organize in ring-like patterns than in stiff 35 kPa microwells. This organization is independent of curvature and significantly more pronounced in 2 kPa microwells with aspect ratio (perimeter/depth) < 25. Physical factors of cells and substrates that drive this behavior are systematically investigated and a mathematical model that explains the organization by balancing the dynamic interaction between tangential cytoskeletal tension, cell-cell, and cell-substrate adhesion is presented. These findings demonstrate the importance of combinatorial effects of geometry and stiffness in complex cellular organization that can be leveraged to facilitate the engineering of bionics and integrated model organoid systems with customized nutrient vascular networks.
Collapse
Affiliation(s)
- Gayatri J. Pahapale
- Department of Chemical and Biomolecular EngineeringJohns Hopkins UniversityBaltimoreMD21218USA
| | - Jiaxiang Tao
- Department of Mechanical EngineeringJohns Hopkins UniversityBaltimoreMD21218USA
| | - Milos Nikolic
- Maryland Biophysics ProgramInstitute for Physical Science and TechnologyUniversity of MarylandCollege ParkMD20742USA
| | - Sammy Gao
- Department of Chemical and Biomolecular EngineeringJohns Hopkins UniversityBaltimoreMD21218USA
| | - Giuliano Scarcelli
- Maryland Biophysics ProgramInstitute for Physical Science and Technology and Fischell Department of BioengineeringUniversity of MarylandCollege ParkMD20742USA
| | - Sean X. Sun
- Department of Mechanical EngineeringCell Biologyand Institute of NanoBioTechnology (INBT)Johns Hopkins UniversityBaltimoreMD21218USA
| | - Lewis H. Romer
- Department of Cell BiologyAnesthesiology and Critical Care MedicineBiomedical EngineeringPediatricsand Center for Cell DynamicsJohns Hopkins School of MedicineBaltimoreMD21205USA
| | - David H. Gracias
- Department of Chemical and Biomolecular EngineeringMaterials Science and EngineeringChemistry and Laboratory for Computational Sensing and Robotics (LCSR)Johns Hopkins UniversityBaltimoreMD21218USA
- Department of Oncology and Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins School of MedicineBaltimoreMD21205USA
| |
Collapse
|
15
|
Zanini G, Scarcelli G. Localization-assisted stimulated Brillouin scattering spectroscopy. APL PHOTONICS 2022; 7:056101. [PMID: 35547354 PMCID: PMC9073852 DOI: 10.1063/5.0087697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Brillouin spectroscopy has emerged as a promising modality to noninvasively probe the mechanical properties of biologically relevant materials. Stimulated Brillouin scattering (SBS) has the potential to improve measurement speed and resolution by exploiting a resonant amplification of the scattered signal, yet current SBS spectrometers have not provided significant improvements due to fundamental and practical limitations of illumination and detection parameters. To overcome this challenge, here we derive a signal localization theory for the Brillouin spectral domain and accordingly design an SBS spectrometer with much improved performances compared to state-of-the-art systems. We present experimental and simulated data validating our theory, which result in a tenfold improvement in acquisition speed, or an order of magnitude improved spectral precision, for SBS spectral measurements when properly optimizing the SBS photon detection architecture.
Collapse
|
16
|
Ambekar YS, Singh M, Schill AW, Zhang J, Zevallos-Delgado C, Khajavi B, Aglyamov SR, Finnell RH, Scarcelli G, Larin KV. Multimodal imaging system combining optical coherence tomography and Brillouin microscopy for neural tube imaging. OPTICS LETTERS 2022; 47:1347-1350. [PMID: 35290310 PMCID: PMC9088521 DOI: 10.1364/ol.453996] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
To understand the dynamics of tissue stiffness during neural tube formation and closure in a murine model, we have developed a multimodal, coaligned imaging system combining optical coherence tomography (OCT) and Brillouin microscopy. Brillouin microscopy can map the longitudinal modulus of tissue but cannot provide structural images. Thus, it is limited for imaging dynamic processes such as neural tube formation and closure. To overcome this limitation, we have combined Brillouin microscopy and OCT in one coaligned instrument. OCT provided depth-resolved structural imaging with a micrometer-scale spatial resolution to guide stiffness mapping by Brillouin modality. 2D structural and Brillouin frequency shift maps were acquired of mouse embryos at gestational day (GD) 8.5, 9.5, and 10.5 with the multimodal system. The results demonstrate the capability of the system to obtain structural and stiffness information simultaneously.
Collapse
Affiliation(s)
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Alexander W. Schill
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Jitao Zhang
- Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA
| | | | - Behzad Khajavi
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Salavat R. Aglyamov
- Department of Mechanical Engineering, University of Houston, Houston, Texas, USA
| | - Richard H. Finnell
- Departments of Molecular and Cell Biology, Molecular and Human Genetics, and Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
17
|
Krug B, Koukourakis N, Guck J, Czarske J. Nonlinear microscopy using impulsive stimulated Brillouin scattering for high-speed elastography. OPTICS EXPRESS 2022; 30:4748-4758. [PMID: 35209449 DOI: 10.1364/oe.449980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
The impulsive stimulated Brillouin microscopy promises fast, non-contact measurements of the elastic properties of biological samples. The used pump-probe approach employs an ultra-short pulse laser and a cw laser to generate Brillouin signals. Modeling of the microscopy technique has already been carried out partially, but not for biomedical applications. The nonlinear relationship between pulse energy and Brillouin signal amplitude is proven with both simulations and experiments. Tayloring of the excitation parameters on the biologically relevant polyacrylamide hydrogels outline sub-ms temporal resolutions at a relative precision of <1%. Brillouin microscopy using the impulsive stimulated scattering therefore exhibits high potential for the measurements of viscoelastic properties of cells and tissues.
Collapse
|
18
|
Carvalho E, Morais M, Ferreira H, Silva M, Guimarães S, Pêgo A. A paradigm shift: Bioengineering meets mechanobiology towards overcoming remyelination failure. Biomaterials 2022; 283:121427. [DOI: 10.1016/j.biomaterials.2022.121427] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 01/31/2022] [Accepted: 02/17/2022] [Indexed: 12/14/2022]
|
19
|
Schlüßler R, Kim K, Nötzel M, Taubenberger A, Abuhattum S, Beck T, Müller P, Maharana S, Cojoc G, Girardo S, Hermann A, Alberti S, Guck J. Correlative all-optical quantification of mass density and mechanics of subcellular compartments with fluorescence specificity. eLife 2022; 11:e68490. [PMID: 35001870 PMCID: PMC8816383 DOI: 10.7554/elife.68490] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 01/08/2022] [Indexed: 01/06/2023] Open
Abstract
Quantitative measurements of physical parameters become increasingly important for understanding biological processes. Brillouin microscopy (BM) has recently emerged as one technique providing the 3D distribution of viscoelastic properties inside biological samples - so far relying on the implicit assumption that refractive index (RI) and density can be neglected. Here, we present a novel method (FOB microscopy) combining BM with optical diffraction tomography and epifluorescence imaging for explicitly measuring the Brillouin shift, RI, and absolute density with specificity to fluorescently labeled structures. We show that neglecting the RI and density might lead to erroneous conclusions. Investigating the nucleoplasm of wild-type HeLa cells, we find that it has lower density but higher longitudinal modulus than the cytoplasm. Thus, the longitudinal modulus is not merely sensitive to the water content of the sample - a postulate vividly discussed in the field. We demonstrate the further utility of FOB on various biological systems including adipocytes and intracellular membraneless compartments. FOB microscopy can provide unexpected scientific discoveries and shed quantitative light on processes such as phase separation and transition inside living cells.
Collapse
Affiliation(s)
- Raimund Schlüßler
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
| | - Kyoohyun Kim
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum für Physik und MedizinErlangenGermany
| | - Martin Nötzel
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
| | - Anna Taubenberger
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
| | - Shada Abuhattum
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum für Physik und MedizinErlangenGermany
| | - Timon Beck
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum für Physik und MedizinErlangenGermany
| | - Paul Müller
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum für Physik und MedizinErlangenGermany
| | - Shovamaye Maharana
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Department of Microbiology and Cell Biology, Indian Institute of ScienceBengaluruIndia
| | - Gheorghe Cojoc
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
| | - Salvatore Girardo
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum für Physik und MedizinErlangenGermany
| | - Andreas Hermann
- Translational Neurodegeneration Section "Albrecht Kossel", University Rostock, and German Center for Neurodegenerative Diseases (DZNE)Rostock/GreifswaldGermany
| | - Simon Alberti
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Physics of Life, Technische Universität DresdenDresdenGermany
| | - Jochen Guck
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische UniversitätDresdenGermany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum für Physik und MedizinErlangenGermany
- Physics of Life, Technische Universität DresdenDresdenGermany
| |
Collapse
|
20
|
Conrad C, Moore K, Polacheck W, Rizvi I, Scarcelli G. Mechanical Modulation of Ovarian Cancer Tumor Nodules Under Flow. IEEE Trans Biomed Eng 2022; 69:294-301. [PMID: 34170820 PMCID: PMC8750319 DOI: 10.1109/tbme.2021.3092641] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Perfusion models are valuable tools to mimic complex features of the tumor microenvironment and to study cell behavior. In ovarian cancer, mimicking disease pathology of ascites has been achieved by seeding tumor nodules on a basement membrane and subjecting them to long-term continuous flow. In this scenario it is particularly important to study the role of mechanical stress on cancer progression. Mechanical cues are already known to be important in key cancer processes such as survival, proliferation, and migration. However, probing cell mechanical properties within microfluidic platforms has not been achievable with current technologies since samples are not easily accessible within most microfluidic channels. METHODS Here, to analyze the mechanical properties of cells within a perfusion chamber, we use Brillouin confocal microscopy, an all-optical technique that requires no contact or perturbation to the sample. RESULTS Our results indicate that ovarian cancer nodules under long-term continuous flow have a significantly lower longitudinal modulus compared to nodules maintained in a static condition. CONCLUSION We further dissect the role of distinct mechanical perturbations (e.g., shear flow, osmolality) on tumor nodule properties. SIGNIFICANCE In summary, the unique combination of a long-term microfluidic culture and noninvasive mechanical analysis technique provides insights on the effects of physical forces in ovarian cancer pathology.
Collapse
|
21
|
Taylor MA, Kijas AW, Wang Z, Lauko J, Rowan AE. Heterodyne Brillouin microscopy for biomechanical imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:6259-6268. [PMID: 34745734 PMCID: PMC8548004 DOI: 10.1364/boe.435869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Microscopic variations in material stiffness play a vital role in cellular scale biomechanics, but are difficult to measure in a natural 3D environment. Brillouin microscopy is a promising technology for such applications, providing non-contact label-free measurement of longitudinal modulus at microscopic resolution. Here we develop heterodyne detection to measure Brillouin scattering signals in a confocal microscope setup, providing sensitive detection with excellent frequency resolution and robust operation in the presence of stray light. The functionality of the microscope is characterized and validated, and the imaging capability demonstrated by imaging structure within both a fibrin fiber network and live cells.
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
Roberts AB, Zhang J, Raj Singh V, Nikolić M, Moeendarbary E, Kamm RD, So PTC, Scarcelli G. Tumor cell nuclei soften during transendothelial migration. J Biomech 2021; 121:110400. [PMID: 33882444 PMCID: PMC8274349 DOI: 10.1016/j.jbiomech.2021.110400] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 02/08/2023]
Abstract
During cancer metastasis, tumor cells undergo significant deformation in order to traverse through endothelial cell junctions in the walls of blood vessels. As cells pass through narrow gaps, smaller than the nuclear diameter, the spatial configuration of chromatin must change along with the distribution of nuclear enzymes. Nuclear stiffness is an important determinant of the ability of cells to undergo transendothelial migration, yet no studies have been conducted to assess whether tumor cell cytoskeletal or nuclear stiffness changes during this critical process in order to facilitate passage. To address this question, we employed two non-contact methods, Brillouin confocal microscopy (BCM) and confocal reflectance quantitative phase microscopy (QPM), to track the changes in mechanical properties of live, transmigrating tumor cells in an in vitro collagen gel platform. Using these two imaging modalities to study transmigrating MDA-MB-231, A549, and A375 cells, we found that both the cells and their nuclei soften upon extravasation and that the nuclear membranes remain soft for at least 24 h. These new data suggest that tumor cells adjust their mechanical properties in order to facilitate extravasation.
Collapse
Affiliation(s)
- Anya B Roberts
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA
| | - Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park 20742, MD, USA
| | - Vijay Raj Singh
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA; Laser Biomedical Research Center, Massachusetts Institute of Technology, Cambridge 02139, MA, USA
| | - Miloš Nikolić
- Maryland Biophysics Program, University of Maryland, College Park, MD 20742, USA
| | - Emad Moeendarbary
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Roger D Kamm
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA.
| | - Peter T C So
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA; Laser Biomedical Research Center, Massachusetts Institute of Technology, Cambridge 02139, MA, USA.
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park 20742, MD, USA; Maryland Biophysics Program, University of Maryland, College Park, MD 20742, USA.
| |
Collapse
|
24
|
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.
Collapse
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.
| |
Collapse
|
25
|
Aleman A, Muralidhar S, Awad AA, Åkerman J, Hanstorp D. Frequency comb enhanced Brillouin microscopy. OPTICS EXPRESS 2020; 28:29540-29552. [PMID: 33114852 DOI: 10.1364/oe.398619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
Brillouin light scattering (BLS) microscopy is a well established and powerful technique to study acoustic and magnetic excitations in the frequency domain with sub-micron spatial resolution. Many other spectroscopic techniques have benefited from the introduction of femtosecond laser sources to optically pump and stimulate the sample under investigation. In BLS microscopy, the use of femtosecond lasers as the excitation source introduces several challenges, primarily since the measured frequency shift is small and the signal levels are weak due to the low duty cycle of typical femtosecond lasers. Here we present a method to evade these challenges. A strong enhancement of the weak scattering amplitude on selected modes is observed by pumping the sample with a high repetition rate frequency comb laser source. The laser beam can be focused to the diffraction limit, providing a micron pumping area. We can thus preserve the innate high frequency and spatial resolution of BLS microscopy. Furthermore, we are able to induce a point-like source of mode-selected elementary excitations which propagate away from the pumping spot. We conclude that we have demonstrated frequency comb pumped BLS microscopy as an attractive tool for studies of ultrafast induced laser dynamics directly in the frequency domain.
Collapse
|
26
|
Ambekar YS, Singh M, Scarcelli G, Rueda EM, Hall BM, Poché RA, Larin KV. Characterization of retinal biomechanical properties using Brillouin microscopy. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200208LR. [PMID: 32981240 PMCID: PMC7519206 DOI: 10.1117/1.jbo.25.9.090502] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/04/2020] [Indexed: 05/03/2023]
Abstract
SIGNIFICANCE The retina is critical for vision, and several diseases may alter its biomechanical properties. However, assessing the biomechanical properties of the retina nondestructively is a challenge due to its fragile nature and location within the eye globe. Advancements in Brillouin spectroscopy have provided the means for nondestructive investigations of retina biomechanical properties. AIM We assessed the biomechanical properties of mouse retinas using Brillouin microscopy noninvasively and showed the potential of Brillouin microscopy to differentiate the type and layers of retinas based on stiffness. APPROACH We used Brillouin microscopy to quantify stiffness of fresh and paraformaldehyde (PFA)-fixed retinas. As further proof-of-concept, we demonstrated a change in the stiffness of a retina with N-methyl-D-aspartate (NMDA)-induced damage, compared to an undamaged sample. RESULTS We found that the retina layers with higher cell body density had higher Brillouin modulus compared to less cell-dense layers. We have also demonstrated that PFA-fixed retina samples were stiffer compared with fresh samples. Further, NMDA-induced neurotoxicity leads to retinal ganglion cell (RGC) death and reactive gliosis, increasing the stiffness of the RGC layer. CONCLUSION Brillouin microscopy can be used to characterize the stiffness distribution of the layers of the retina and can be used to differentiate tissue at different conditions based on biomechanical properties.
Collapse
Affiliation(s)
- Yogeshwari S. Ambekar
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Manmohan Singh
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Giuliano Scarcelli
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
| | - Elda M. Rueda
- Baylor College of Medicine, Department of Molecular Physiology and Biophysics, Houston, Texas, United States
| | - Benjamin M. Hall
- Baylor College of Medicine, Department of Molecular Physiology and Biophysics, Houston, Texas, United States
| | - Ross A. Poché
- Baylor College of Medicine, Department of Molecular Physiology and Biophysics, Houston, Texas, United States
- Address all correspondence to Ross A. Poché, E-mail: ; Kirill V. Larin, E-mail:
| | - Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Baylor College of Medicine, Department of Molecular Physiology and Biophysics, Houston, Texas, United States
- Address all correspondence to Ross A. Poché, E-mail: ; Kirill V. Larin, E-mail:
| |
Collapse
|
27
|
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.
Collapse
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.
| |
Collapse
|
28
|
Wisniewski EO, Mistriotis P, Bera K, Law RA, Zhang J, Nikolic M, Weiger M, Parlani M, Tuntithavornwat S, Afthinos A, Zhao R, Wirtz D, Kalab P, Scarcelli G, Friedl P, Konstantopoulos K. Dorsoventral polarity directs cell responses to migration track geometries. SCIENCE ADVANCES 2020; 6:eaba6505. [PMID: 32789173 PMCID: PMC7399493 DOI: 10.1126/sciadv.aba6505] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/12/2020] [Indexed: 05/02/2023]
Abstract
How migrating cells differentially adapt and respond to extracellular track geometries remains unknown. Using intravital imaging, we demonstrate that invading cells exhibit dorsoventral (top-to-bottom) polarity in vivo. To investigate the impact of dorsoventral polarity on cell locomotion through different confining geometries, we fabricated microchannels of fixed cross-sectional area, albeit with distinct aspect ratios. Vertical confinement, exerted along the dorsoventral polarity axis, induces myosin II-dependent nuclear stiffening, which results in RhoA hyperactivation at the cell poles and slow bleb-based migration. In lateral confinement, directed perpendicularly to the dorsoventral polarity axis, the absence of perinuclear myosin II fails to increase nuclear stiffness. Hence, cells maintain basal RhoA activity and display faster mesenchymal migration. In summary, by integrating microfabrication, imaging techniques, and intravital microscopy, we demonstrate that dorsoventral polarity, observed in vivo and in vitro, directs cell responses in confinement by spatially tuning RhoA activity, which controls bleb-based versus mesenchymal migration.
Collapse
Affiliation(s)
- Emily O. Wisniewski
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Panagiotis Mistriotis
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical Engineering, Auburn University, Auburn, AL 36849, USA
| | - Kaustav Bera
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Robert A. Law
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Milos Nikolic
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Maryland Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - Michael Weiger
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Maria Parlani
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Soontorn Tuntithavornwat
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Alexandros Afthinos
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Runchen Zhao
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Physical Sciences Oncology Center, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Oncology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Petr Kalab
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Peter Friedl
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
- Cancer Genomics Centre, 3584 Utrecht, Netherlands
| | - Konstantinos Konstantopoulos
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Physical Sciences Oncology Center, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Oncology, Johns Hopkins University, Baltimore, MD 21205, USA
| |
Collapse
|
29
|
Webb JN, Zhang H, Sinha Roy A, Randleman JB, Scarcelli G. Detecting Mechanical Anisotropy of the Cornea Using Brillouin Microscopy. Transl Vis Sci Technol 2020; 9:26. [PMID: 32832232 PMCID: PMC7414627 DOI: 10.1167/tvst.9.7.26] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022] Open
Abstract
Purpose The purpose of this study was to detect the mechanical anisotropy of the cornea using Brillouin microscopy along different perturbation directions. Methods Brillouin frequency shift of both whole globes (n = 10) and cornea punches (n = 10) were measured at different angles to the incident laser, thereby probing corneal longitudinal modulus of elasticity along different directions. Frequency shift of virgin (n = 26) versus cross-linked corneas (n = 15) over a large range of hydration conditions were compared in order to differentiate the contributions to Brillouin shift due to hydration from those due to stromal tissue. Results We detected mechanical anisotropy of corneas, with an average frequency shift increase of 53 MHz and 96 MHz when the instrument probed from 0° to 15° and 30° along the direction of the stromal fibers. Brillouin microscopy did not lose sensitivity to mechanical anisotropy up to 96% water content. We experimentally measured and theoretically modeled how mechanical changes independent of hydration affect frequency shift as a result of corneal cross-linking by isolating an approximately 100 MHz increase in frequency shift following a cross-linking procedure purely due to changes of stromal tissue mechanics. Conclusions Brillouin microscopy is sensitive to mechanical anisotropy of the stroma even in highly hydrated corneas. The agreement between model and experimental data suggested a quantitative relationship between Brillouin frequency shift, hydration state of the cornea, and stromal tissue stiffness. Translational Relevance The protocol and model validated throughout this study offer a path for comprehensive measurements of corneal mechanics within the clinic; allowing for improved evaluation of the long-term mechanical efficacy of cross-linking procedures.
Collapse
Affiliation(s)
- Joshua N Webb
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Hongyuan Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.,Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | | | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| |
Collapse
|
30
|
Antonacci G, Beck T, Bilenca A, Czarske J, Elsayad K, Guck J, Kim K, Krug B, Palombo F, Prevedel R, Scarcelli G. Recent progress and current opinions in Brillouin microscopy for life science applications. Biophys Rev 2020; 12:615-624. [PMID: 32458371 PMCID: PMC7311586 DOI: 10.1007/s12551-020-00701-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/07/2020] [Indexed: 12/20/2022] Open
Abstract
Many important biological functions and processes are reflected in cell and tissue mechanical properties such as elasticity and viscosity. However, current techniques used for measuring these properties have major limitations, such as that they can often not measure inside intact cells and/or require physical contact-which cells can react to and change. Brillouin light scattering offers the ability to measure mechanical properties in a non-contact and label-free manner inside of objects with high spatial resolution using light, and hence has emerged as an attractive method during the past decade. This new approach, coined "Brillouin microscopy," which integrates highly interdisciplinary concepts from physics, engineering, and mechanobiology, has led to a vibrant new community that has organized itself via a European funded (COST Action) network. Here we share our current assessment and opinion of the field, as emerged from a recent dedicated workshop. In particular, we discuss the prospects towards improved and more bio-compatible instrumentation, novel strategies to infer more accurate and quantitative mechanical measurements, as well as our current view on the biomechanical interpretation of the Brillouin spectra.
Collapse
Affiliation(s)
- Giuseppe Antonacci
- Photonics Research Group, INTEC, Ghent University-imec, 9052, Ghent, Belgium
- Present address: Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milan, Italy
| | - Timon Beck
- Biotechnology Center, TU Dresden, Dresden, Germany
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Alberto Bilenca
- Biomedical Engineering Department, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Jürgen Czarske
- Laboratory of Measurement and Sensor System Technique, TU Dresden, Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
| | - Kareem Elsayad
- Advanced Microscopy, Vienna Biocenter Core Facilities (VBCF), Vienna, Austria.
| | - Jochen Guck
- Biotechnology Center, TU Dresden, Dresden, Germany
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Kyoohyun Kim
- Biotechnology Center, TU Dresden, Dresden, Germany
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Benedikt Krug
- Laboratory of Measurement and Sensor System Technique, TU Dresden, Dresden, Germany
| | | | - Robert Prevedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| |
Collapse
|
31
|
Zhang J, Alisafaei F, Nikolić M, Nou XA, Kim H, Shenoy VB, Scarcelli G. Nuclear Mechanics within Intact Cells Is Regulated by Cytoskeletal Network and Internal Nanostructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1907688. [PMID: 32243075 PMCID: PMC7799396 DOI: 10.1002/smll.201907688] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/05/2020] [Accepted: 03/05/2020] [Indexed: 05/11/2023]
Abstract
The mechanical properties of the cellular nucleus are extensively studied as they play a critical role in important processes, such as cell migration, gene transcription, and stem cell differentiation. While the mechanical properties of the isolated nucleus have been tested, there is a lack of measurements about the mechanical behavior of the nucleus within intact cells and specifically about the interplay of internal nuclear components with the intracellular microenvironment, because current testing methods are based on contact and only allow studying the nucleus after isolation from a cell or disruption of cytoskeleton. Here, all-optical Brillouin microscopy and 3D chemomechanical modeling are used to investigate the regulation of nuclear mechanics in physiological conditions. It is observed that the nuclear modulus can be modulated by epigenetic regulation targeting internal nuclear nanostructures such as lamin A/C and chromatin. It is also found that nuclear modulus is strongly regulated by cytoskeletal behavior through a robust mechanism conserved in different culturing conditions. Given the active role of cytoskeletal modulation in nearly all cell functions, this work will enable to reveal highly relevant mechanisms of nuclear mechanical regulations in physiological and pathological conditions.
Collapse
Affiliation(s)
- Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Farid Alisafaei
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, PA, 19104, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, PA, 19104, USA
| | - Miloš Nikolić
- Maryland Biophysics Program, University of Maryland, College Park, MD 20742, USA
| | - Xuefei A. Nou
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Hanyoup Kim
- Canon U.S. Life Sciences, Inc., 9800 Medical Center Drive, Suite C-120, Rockville, MD 20850, USA
| | - Vivek B. Shenoy
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, PA, 19104, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, PA, 19104, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Maryland Biophysics Program, University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
32
|
Ambekar YS, Singh M, Zhang J, Nair A, Aglyamov SR, Scarcelli G, Larin KV. Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:2041-2051. [PMID: 32341865 PMCID: PMC7173892 DOI: 10.1364/boe.387361] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/27/2020] [Accepted: 03/05/2020] [Indexed: 05/03/2023]
Abstract
Assessing the biomechanical properties of the crystalline lens can provide crucial information for diagnosing disease and guiding precision therapeutic interventions. Existing noninvasive methods have been limited to global measurements. Here, we demonstrate the quantitative assessment of the elasticity of crystalline lens with a multimodal optical elastography technique, which combines dynamic wave-based optical coherence elastography (OCE) and Brillouin microscopy to overcome the drawbacks of individual modalities. OCE can provide direct measurements of tissue elasticity rapidly and quantitatively, but it is a challenge to image transparent samples such as the lens because this technique relies on backscattered light. On the other hand, Brillouin microscopy can map the longitudinal modulus with micro-scale resolution in transparent samples. However, the relationship between Brillouin-deduced modulus and Young's modulus is not straightforward and sample dependent. By combining these two techniques, we can calibrate Brillouin measurements with OCE, based on the same sample, allowing us to completely map the Young's modulus of the crystalline lens. The combined system was first validated with tissue-mimicking gelatin phantoms of varying elasticities (N = 9). The OCE data was used to calibrate the Brillouin shift measurements and subsequently map the Young's modulus of the phantoms. After validation, OCE and Brillouin measurements were performed on ex-vivo porcine lenses (N = 6), and the Young's modulus of the lenses was spatially mapped. The results show a strong correlation between Young's moduli measured by OCE and longitudinal moduli measured by Brillouin microscopy. The correlation coefficient R was 0.98 for the phantoms and 0.94 for the lenses, respectively. The mean Young's modulus of the anterior and posterior lens was 1.98 ± 0.74 kPa and 2.93 ± 1.13 kPa, respectively, and the Young's modulus of the lens nucleus was 11.90 ± 2.94 kPa. The results presented in this manuscript open a new way for truly quantitative biomechanical mapping of optically transparent (or low scattering) tissues in 3D.
Collapse
Affiliation(s)
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, TX 77030, USA
| | - Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Achuth Nair
- Department of Biomedical Engineering, University of Houston, Houston, TX 77030, USA
| | - Salavat R. Aglyamov
- Department of Mechanical Engineering, University of Houston, Houston, TX 77030, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, TX 77030, USA
- Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
33
|
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.
Collapse
Affiliation(s)
- Kareem Elsayad
- Advanced Microscopy, VBCF, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna A-1030, Austria.
| |
Collapse
|
34
|
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.
Collapse
|
35
|
Elsayad K, Polakova S, Gregan J. Probing Mechanical Properties in Biology Using Brillouin Microscopy. Trends Cell Biol 2019; 29:608-611. [DOI: 10.1016/j.tcb.2019.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 01/01/2023]
|
36
|
Elsayad K, Palombo F, Dehoux T, Fioretto D. Brillouin Light Scattering Microspectroscopy for Biomedical Research and Applications: introduction to feature issue. BIOMEDICAL OPTICS EXPRESS 2019; 10:2670-2673. [PMID: 31143507 PMCID: PMC6524607 DOI: 10.1364/boe.10.002670] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Indexed: 06/09/2023]
Abstract
There has been a marked revival of interest in brillouin light scattering spectroscopy/microscopy over the last decade in regards to applications related to all optically studying the mechanical problems associated with systems of biological and medical interest. This revival has been driven by advancements in spectrometer design, together with mounting evidence of the critical role that mechanical properties can play in biological processes as well as the onset of diverse diseases. This feature issue contains a series of papers spanning some of the latest developments in the field of Brillouin light scattering spectroscopy and microscopy as applied to systems of biomedical interest.
Collapse
Affiliation(s)
- Kareem Elsayad
- VBCF-Advanced Microscopy, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna, A-1030, Austria
| | - Francesca Palombo
- School of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK
| | - Thomas Dehoux
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, Villeurbanne, France
| | - Daniele Fioretto
- Istituto Officina dei Materiali del CNR (CNR-IOM) - Unita` di Perugia, c/o Dipartimento di Fisica e Geologia, Perugia I-06100, Italy
| |
Collapse
|