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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 DOI: 10.1038/s41467-024-49419-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
Acoustic vibrations of matter convey fundamental viscoelastic information that can be optically retrieved by hyperfine spectral analysis of the inelastic Brillouin scattered light. Increasing evidence of the central role of the viscoelastic properties in biological processes has stimulated the rise of non-contact Brillouin microscopy, yet this method faces challenges in turbid samples due to overwhelming elastic background light. Here, we introduce a common-path Birefringence-Induced Phase Delay (BIPD) filter to disentangle the polarization states of the Brillouin and Rayleigh signals, enabling the rejection of the background light using a polarizer. We demonstrate a 65 dB extinction ratio in a single optical pass collecting Brillouin spectra in extremely scattering environments and across highly reflective interfaces. We further employ the BIPD filter to image bone tissues from a mouse model of osteopetrosis, highlighting altered biomechanical properties compared to the healthy control. Results herald new opportunities in mechanobiology where turbid biological samples remain poorly characterized.
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Affiliation(s)
| | - Renzo Vanna
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Marco Ventura
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | | | - Cristina Sobacchi
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089, Rozzano (Milano), Italy
- CNR-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), UOS di Milano, via Fantoli 16/15, 20138, Milano, Italy
| | - Morteza Behrouzitabar
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Dario Polli
- Specto Photonics, Via Giulio e Corrado Venini 18, 20127, Milano, Italy
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Cristian Manzoni
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy.
| | - Giulio Cerullo
- CNR-Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
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2
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Ibrahim KA, Naidu AS, Miljkovic H, Radenovic A, Yang W. Label-Free Techniques for Probing Biomolecular Condensates. ACS NANO 2024; 18:10738-10757. [PMID: 38609349 DOI: 10.1021/acsnano.4c01534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
Biomolecular condensates play important roles in a wide array of fundamental biological processes, such as cellular compartmentalization, cellular regulation, and other biochemical reactions. Since their discovery and first observations, an extensive and expansive library of tools has been developed to investigate various aspects and properties, encompassing structural and compositional information, material properties, and their evolution throughout the life cycle from formation to eventual dissolution. This Review presents an overview of the expanded set of tools and methods that researchers use to probe the properties of biomolecular condensates across diverse scales of length, concentration, stiffness, and time. In particular, we review recent years' exciting development of label-free techniques and methodologies. We broadly organize the set of tools into 3 categories: (1) imaging-based techniques, such as transmitted-light microscopy (TLM) and Brillouin microscopy (BM), (2) force spectroscopy techniques, such as atomic force microscopy (AFM) and the optical tweezer (OT), and (3) microfluidic platforms and emerging technologies. We point out the tools' key opportunities, challenges, and future perspectives and analyze their correlative potential as well as compatibility with other techniques. Additionally, we review emerging techniques, namely, differential dynamic microscopy (DDM) and interferometric scattering microscopy (iSCAT), that have huge potential for future applications in studying biomolecular condensates. Finally, we highlight how some of these techniques can be translated for diagnostics and therapy purposes. We hope this Review serves as a useful guide for new researchers in this field and aids in advancing the development of new biophysical tools to study biomolecular condensates.
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3
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La Cavera S, Chauhan VM, Hardiman W, Yao M, Fuentes-Domínguez R, Setchfield K, Abayzeed SA, Pérez-Cota F, Smith RJ, Clark M. Label-free Brillouin endo-microscopy for the quantitative 3D imaging of sub-micrometre biology. Commun Biol 2024; 7:451. [PMID: 38622287 PMCID: PMC11018753 DOI: 10.1038/s42003-024-06126-4] [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: 07/17/2023] [Accepted: 03/29/2024] [Indexed: 04/17/2024] Open
Abstract
This report presents an optical fibre-based endo-microscopic imaging tool that simultaneously measures the topographic profile and 3D viscoelastic properties of biological specimens through the phenomenon of time-resolved Brillouin scattering. This uses the intrinsic viscoelasticity of the specimen as a contrast mechanism without fluorescent tags or photoacoustic contrast mechanisms. We demonstrate 2 μm lateral resolution and 320 nm axial resolution for the 3D imaging of biological cells and Caenorhabditis elegans larvae. This has enabled the first ever 3D stiffness imaging and characterisation of the C. elegans larva cuticle in-situ. A label-free, subcellular resolution, and endoscopic compatible technique that reveals structural biologically-relevant material properties of tissue could pave the way toward in-vivo elasticity-based diagnostics down to the single cell level.
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Affiliation(s)
- Salvatore La Cavera
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - Veeren M Chauhan
- Advanced Materials & Healthcare Technologies, School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - William Hardiman
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Mengting Yao
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Rafael Fuentes-Domínguez
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Kerry Setchfield
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Sidahmed A Abayzeed
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Fernando Pérez-Cota
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Richard J Smith
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Matt Clark
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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4
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Komninou MA, Seiler TG, Enzmann V. Corneal biomechanics and diagnostics: a review. Int Ophthalmol 2024; 44:132. [PMID: 38478103 PMCID: PMC10937779 DOI: 10.1007/s10792-024-03057-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 02/16/2024] [Indexed: 03/17/2024]
Abstract
PURPOSE Corneal biomechanics is an emerging field and the interest into physical and biological interrelations in the anterior part of the eye has significantly increased during the past years. There are many factors that determine corneal biomechanics such as hormonal fluctuations, hydration and environmental factors. Other factors that can affect the corneas are the age, the intraocular pressure and the central corneal thickness. The purpose of this review is to evaluate the factors affecting corneal biomechanics and the recent advancements in non-destructive, in vivo measurement techniques for early detection and improved management of corneal diseases. METHODS Until recently, corneal biomechanics could not be directly assessed in humans and were instead inferred from geometrical cornea analysis and ex vivo biomechanical testing. The current research has made strides in studying and creating non-destructive and contactless techniques to measure the biomechanical properties of the cornea in vivo. RESULTS Research has indicated that altered corneal biomechanics contribute to diseases such as keratoconus and glaucoma. The identification of pathological corneas through the new measurement techniques is imperative for preventing postoperative complications. CONCLUSIONS Identification of pathological corneas is crucial for the prevention of postoperative complications. Therefore, a better understanding of corneal biomechanics will lead to earlier diagnosis of ectatic disorders, improve current refractive surgeries and allow for a better postoperative treatment.
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Affiliation(s)
- Maria Angeliki Komninou
- Department of Ophthalmology, Bern University Hospital Inselspital, University of Bern, Bern, Switzerland
- Institute of Intensive Care Medicine, University Hospital Zurich & University of Zurich, Zurich, Switzerland
| | - Theo G Seiler
- Department of Ophthalmology, Bern University Hospital Inselspital, University of Bern, Bern, Switzerland
- Klinik Für Augenheilkunde, Universitätsklinikum Düsseldorf, Düsseldorf, Germany
- Institut Für Refraktive Und Opthalmo-Chirurgie (IROC), Zurich, Switzerland
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Volker Enzmann
- Department of Ophthalmology, Bern University Hospital Inselspital, University of Bern, Bern, Switzerland.
- Department of BioMedical Research, University of Bern, Bern, Switzerland.
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5
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Romodina MN, Parmar A, Singh K. In vivo measurement of the biomechanical properties of human skin with motion-corrected Brillouin microscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:1777-1784. [PMID: 38495685 PMCID: PMC10942711 DOI: 10.1364/boe.516032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/18/2024] [Accepted: 01/30/2024] [Indexed: 03/19/2024]
Abstract
Biomechanical testing of human skin in vivo is important to study the aging process and pathological conditions such as skin cancer. Brillouin microscopy allows the all-optical, non-contact visualization of the mechanical properties of cells and tissues over space. Here, we use the combination of Brillouin microscopy and optical coherence tomography for motion-corrected, depth-resolved biomechanical testing of human skin in vivo. We obtained two peaks in the Brillouin spectra for the epidermis, the first at 7 GHz and the second near 9-10 GHz. The experimentally measured Brillouin frequency shift of the dermis is lower compared to the epidermis and is 6.8 GHz, indicating the lower stiffness of the dermis.
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Affiliation(s)
- Maria N. Romodina
- Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany
| | - Asha Parmar
- Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany
- Department of Physics, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Kanwarpal Singh
- Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany
- Department of Physics, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Department of Electrical and Computer Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
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6
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Yang F, Bevilacqua C, Hambura S, Neves A, Gopalan A, Watanabe K, Govendir M, Bernabeu M, Ellenberg J, Diz-Muñoz A, Köhler S, Rapti G, Jechlinger M, Prevedel R. Pulsed stimulated Brillouin microscopy enables high-sensitivity mechanical imaging of live and fragile biological specimens. Nat Methods 2023; 20:1971-1979. [PMID: 37884795 PMCID: PMC10703689 DOI: 10.1038/s41592-023-02054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
Brillouin microscopy is an emerging optical elastography technique capable of assessing mechanical properties of biological samples in a three-dimensional, all-optical and noncontact fashion. The typically weak Brillouin scattering signal can be substantially enhanced via a stimulated Brillouin scattering (SBS) process; however, current implementations require high pump powers, which prohibit applications to photosensitive or live imaging of biological samples. Here we present a pulsed SBS scheme that takes advantage of the nonlinearity of the pump-probe interaction. In particular, we show that the required pump laser power can be decreased ~20-fold without affecting the signal levels or spectral precision. We demonstrate the low phototoxicity and high specificity of our pulsed SBS approach by imaging, with subcellular detail, sensitive single cells, zebrafish larvae, mouse embryos and adult Caenorhabditis elegans. Furthermore, our method permits observing the mechanics of organoids and C. elegans embryos over time, opening up further possibilities for the field of mechanobiology.
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Affiliation(s)
- Fan Yang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China.
| | - Carlo Bevilacqua
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Sebastian Hambura
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ana Neves
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Anusha Gopalan
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Koki Watanabe
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Matt Govendir
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- European Molecular Biology Laboratory Barcelona, Barcelona, Spain
| | - Maria Bernabeu
- European Molecular Biology Laboratory Barcelona, Barcelona, Spain
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Simone Köhler
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Georgia Rapti
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Rome, Italy
| | - Martin Jechlinger
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- MOLIT Institute for Personalized Medicine gGmbH, Heilbronn, Germany
| | - Robert Prevedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany.
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Rome, Italy.
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- German Center for Lung Research (DZL), Heidelberg, Germany.
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7
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Pérez-Cota F, Martínez-Arellano G, La Cavera S, Hardiman W, Thornton L, Fuentes-Domínguez R, Smith RJ, McIntyre A, Clark M. Classification of cancer cells at the sub-cellular level by phonon microscopy using deep learning. Sci Rep 2023; 13:16228. [PMID: 37758808 PMCID: PMC10533877 DOI: 10.1038/s41598-023-42793-9] [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: 04/17/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
There is a consensus about the strong correlation between the elasticity of cells and tissue and their normal, dysplastic, and cancerous states. However, developments in cell mechanics have not seen significant progress in clinical applications. In this work, we explore the possibility of using phonon acoustics for this purpose. We used phonon microscopy to obtain a measure of the elastic properties between cancerous and normal breast cells. Utilising the raw time-resolved phonon-derived data (300 k individual inputs), we employed a deep learning technique to differentiate between MDA-MB-231 and MCF10a cell lines. We achieved a 93% accuracy using a single phonon measurement in a volume of approximately 2.5 μm3. We also investigated means for classification based on a physical model that suggest the presence of unidentified mechanical markers. We have successfully created a compact sensor design as a proof of principle, demonstrating its compatibility for use with needles and endoscopes, opening up exciting possibilities for future applications.
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Affiliation(s)
- Fernando Pérez-Cota
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK.
| | | | - Salvatore La Cavera
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
| | - William Hardiman
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
| | - Luke Thornton
- Biodiscovery Institute, Centre for Cancer Sciences, School of Medicine, University of Nottingham, Nottingham, UK
| | | | - Richard J Smith
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
| | - Alan McIntyre
- Biodiscovery Institute, Centre for Cancer Sciences, School of Medicine, University of Nottingham, Nottingham, UK
| | - Matt Clark
- Optics and Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
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8
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Salzenstein P, Wu TY. Uncertainty Estimation for the Brillouin Frequency Shift Measurement Using a Scanning Tandem Fabry-Pérot Interferometer. MICROMACHINES 2023; 14:1429. [PMID: 37512740 PMCID: PMC10386179 DOI: 10.3390/mi14071429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
The expanded uncertainty of the measured Brillouin scattering shift frequencies is essential in assessing the measurements of parameters of various materials. We describe the general operation principles of a Brillouin light scattering (BLS) spectrometer with a high-power laser and a scanning tandem Fabry-Pérot interferometer (TFPI) for material characterization. Various uncertainty components have been analyzed for the BLS spectrometer following the Guide to the Expression of Uncertainty in Measurement (GUM). The expanded relative uncertainty in the measured Brillouin frequency shift of 15.70 GHz for polymethyl methacrylate (PMMA) was estimated to be 0.26%. The calculated Brillouin frequency shift (based on material properties of PMMA) was determined to be 15.44 GHz with expanded relative uncertainty of 2.13%. It was shown that the measured and calculated Brillouin frequency shifts for PMMA agree within their expanded uncertainties. The TFPI-based BLS spectrometer can be used to measure the longitudinal modulus of materials with an expanded uncertainty of 1.9%, which is smaller than that of the ultrasonic velocity-based method (estimated to be 2.9%).
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Affiliation(s)
- Patrice Salzenstein
- Centre National de la Recherche Scientifique (CNRS), Franche-Comté Electronique Mécanique Thermique Optique Sciences et Technologies (FEMTO-ST) Institute, Université de Franche-Comté (UFC), 25030 Besançon, France
| | - Thomas Y Wu
- National Metrology Centre (NMC), Agency for Science, Technology and Research (A*STAR), 8 CleanTech Loop, #01-20, Singapore 637145, Singapore
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9
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Chow DM, Yun SH. Pulsed stimulated Brillouin microscopy. OPTICS EXPRESS 2023; 31:19818-19827. [PMID: 37381389 PMCID: PMC10316751 DOI: 10.1364/oe.489158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/24/2023] [Accepted: 05/10/2023] [Indexed: 06/30/2023]
Abstract
Stimulated Brillouin scattering is an emerging technique for probing the mechanical properties of biological samples. However, the nonlinear process requires high optical intensities to generate sufficient signal-to-noise ratio (SNR). Here, we show that the SNR of stimulated Brillouin scattering can exceed that of spontaneous Brillouin scattering with the same average power levels suitable for biological samples. We verify the theoretical prediction by developing a novel scheme using low duty cycle, nanosecond pulses for the pump and probe. A shot noise-limited SNR over 1000 was measured with a total average power of 10 mW for 2 ms or 50 mW for 200 µs integration on water samples. High-resolution maps of Brillouin frequency shift, linewidth, and gain amplitude from cells in vitro are obtained with a spectral acquisition time of 20 ms. Our results demonstrate the superior SNR of pulsed stimulated Brillouin over spontaneous Brillouin microscopy.
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Affiliation(s)
- Desmond M. Chow
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Seok-Hyun Yun
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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10
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O’Connor SP, Doktor DA, Scully MO, Yakovlev VV. Spectral resolution enhancement for impulsive stimulated Brillouin spectroscopy by expanding pump beam geometry. OPTICS EXPRESS 2023; 31:14604-14616. [PMID: 37157321 PMCID: PMC10316680 DOI: 10.1364/oe.487131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 05/10/2023]
Abstract
Brillouin microscopy has recently emerged as a powerful tool for mechanical property measurements in biomedical sensing and imaging applications. Impulsive stimulated Brillouin scattering (ISBS) microscopy has been proposed for faster and more accurate measurements, which do not rely on stable narrow-band lasers and thermally-drifting etalon-based spectrometers. However, the spectral resolution of ISBS-based signal has not been significantly explored. In this report, the ISBS spectral profile has been investigated as a function of the pump beam's spatial geometry, and novel methodologies have been developed for accurate spectral assessment. The ISBS linewidth was found to consistently decrease with increasing pump-beam diameter. These findings provide the means for improved spectral resolution measurements and pave the way to broader applications of ISBS microscopy.
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Affiliation(s)
- Sean P. O’Connor
- Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
| | - Dominik A. Doktor
- Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
| | - Marlan O. Scully
- Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
- Department of Physics, Baylor University, Waco, TX 76798, USA
| | - Vladislav V. Yakovlev
- Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
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11
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Passeri AA, Di Michele A, Neri I, Cottone F, Fioretto D, Mattarelli M, Caponi S. Size and environment: The effect of phonon localization on micro-Brillouin imaging. BIOMATERIALS ADVANCES 2023; 147:213341. [PMID: 36827851 DOI: 10.1016/j.bioadv.2023.213341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/19/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Specifically designed samples have been analyzed to test the ability of Brillouin spectroscopy to provide reliable mechanical characterization of micro and nano-objects. The selected samples are polymeric films, whose transversal sizes from hundreds of nano- to some micro-meters cover the entire range of length-scales relevant in Brillouin scattering process. The experimental data highlight how, the size of the extended collective oscillation (acoustic phonons, in brief) is the lowest spatial resolution reachable in Brillouin mechanical characterization. Conversely, in the limit condition of phonon confinement, the technique provides the mechanical properties of nano-objects whose characteristic size is comparable with the phonon wavelength (⁓300 nm). Investigating acoustically heterogeneous materials, both size of heterogeneity and acoustic mismatch between adjacent regions are shown to be relevant in shaping the Brillouin response. In particular, a transition from a confined to a non-confined condition is obtained modulating the acoustic mismatch between the micro-objects and their local environment. The provided results and the derived analytic models for the data analysis will guide the interpretation of Brillouin spectra acquired in complex nano-structured samples such as cells, tissues or biomimetic materials. Our analysis can therefore generate new insights to tackle fundamental problems in mechanobiology or to characterize new bioengineered materials.
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Affiliation(s)
- A A Passeri
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy
| | - A Di Michele
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy
| | - I Neri
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy
| | - F Cottone
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy
| | - D Fioretto
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy; CEMIN, Centre of Excellence on Nanostructured Innovative Materials, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - M Mattarelli
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06100 Perugia, Italy.
| | - S Caponi
- Istituto Officina dei Materiali, National Research Council (IOM-CNR), Unit of Perugia, c/o Department of Physics and Geology, University of Perugia, Via A. Pascoli, I-06123 Perugia, Italy.
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12
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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.
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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
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13
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Bevilacqua C, Gomez JM, Fiuza UM, Chan CJ, Wang L, Hambura S, Eguren M, Ellenberg J, Diz-Muñoz A, Leptin M, Prevedel R. High-resolution line-scan Brillouin microscopy for live imaging of mechanical properties during embryo development. Nat Methods 2023; 20:755-760. [PMID: 36997817 PMCID: PMC10172129 DOI: 10.1038/s41592-023-01822-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 02/17/2023] [Indexed: 04/01/2023]
Abstract
Brillouin microscopy can assess mechanical properties of biological samples in a three-dimensional (3D), all-optical and hence non-contact fashion, but its weak signals often lead to long imaging times and require an illumination dosage harmful for living organisms. Here, we present a high-resolution line-scanning Brillouin microscope for multiplexed and hence fast 3D imaging of dynamic biological processes with low phototoxicity. The improved background suppression and resolution, in combination with fluorescence light-sheet imaging, enables the visualization of the mechanical properties of cells and tissues over space and time in living organism models such as fruit flies, ascidians and mouse embryos.
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Affiliation(s)
- Carlo Bevilacqua
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Juan Manuel Gomez
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ulla-Maj Fiuza
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Systems Bioengineering, MELIS, Universidad Pompeu Fabra, Barcelona, Spain
| | - Chii Jou Chan
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ling Wang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Sebastian Hambura
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Manuel Eguren
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Maria Leptin
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Robert Prevedel
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Monterotondo, Italy.
- Molecular Medicine Partnership Unit (MMPU), European Molecular Biology Laboratory, Heidelberg, Germany.
- German Center for Lung Research (DZL), Heidelberg, Germany.
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany.
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14
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Zhang J, Nikolic M, Tanner K, Scarcelli G. Rapid biomechanical imaging at low irradiation level via dual line-scanning Brillouin microscopy. Nat Methods 2023; 20:677-681. [PMID: 36894684 PMCID: PMC10363327 DOI: 10.1038/s41592-023-01816-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 02/13/2023] [Indexed: 03/11/2023]
Abstract
Brillouin microscopy is a technique for mechanical characterization of biological material without contact at high three-dimensional resolution. Here, we introduce dual line-scanning Brillouin microscopy (dLSBM), which improves acquisition speed and reduces irradiation dose by more than one order of magnitude with selective illumination and single-shot analysis of hundreds of points along the incident beam axis. Using tumor spheroids, we demonstrate the ability to capture the sample response to rapid mechanical perturbations as well as the spatially resolved evolution of the mechanical properties in growing spheroids.
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Affiliation(s)
- Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA.
| | - Milos Nikolic
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
- Maryland Biophysics Program, University of Maryland, College Park, MD, USA
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kandice Tanner
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.
- Maryland Biophysics Program, University of Maryland, College Park, MD, USA.
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15
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Chen B, Bai Z, Hun X, Wang J, Cui C, Qi Y, Yan B, Ding J, Wang K, Wang Y, Lu Z. Gain characteristics of stimulated Brillouin scattering in fused silica. OPTICS EXPRESS 2023; 31:5699-5707. [PMID: 36823843 DOI: 10.1364/oe.480391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Stimulated Brillouin scattering (SBS) is a non-linear process which has the capacity to improve the beam quality and pulse characteristics of laser beams. In this paper, we theoretically and experimentally study the process of SBS in fused silica. In particular, we examine the energy reflection and pulse compression of input laser pulses as functions of focus position, pump energy and beam diameter. We utilized coupled wave equations and a distributed noise model to simulate the reflected energy and time waveform under different gain parameters. An experimental system is constructed and used to qualify the numerical simulations. The results reveal that the threshold for the SBS process and the energy reflectivity significantly change with laser focus position under the same pump and focusing parameters. Ultimately, the gain characteristics of the SBS material is the primary factor that influences the SBS output. This work presented here offers insight into the operation of short-length solid-state SBS lasers and serves as a basis for the design and optimization of such systems.
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16
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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.
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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
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17
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Techniques for In Vivo Assessment of Corneal Biomechanics: Brillouin Spectroscopy and Hydration State - Quo Vadis? Klin Monbl Augenheilkd 2022; 239:1427-1432. [PMID: 35977709 DOI: 10.1055/a-1926-5249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To assess the structural integrity of the cornea, non-invasive methods are needed for the local measurement of its mechanical properties. Among a number of established techniques and their associated advantages and disadvantages, Brillouin spectroscopy is still a relatively new technique, capable of determining the compressive modulus of biological tissue, specifically the cornea, in vivo. In the present paper, these various existing and developing technologies for corneal biomechanics are discussed and correlated.
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18
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Li T, Li F, Liu X, Yakovlev VV, Agarwal GS. Quantum-enhanced stimulated Brillouin scattering spectroscopy and imaging. OPTICA 2022; 9:959-964. [PMID: 37398895 PMCID: PMC10312138 DOI: 10.1364/optica.467635] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/14/2022] [Indexed: 07/04/2023]
Abstract
Brillouin microscopy is an emerging label-free imaging technique used to assess local viscoelastic properties. Quantum-enhanced stimulated Brillouin scattering is demonstrated using low power continuous-wave lasers at 795 nm. A signal-to-noise ratio enhancement of 3.4 dB is reported by using two-mode intensity-difference squeezed light generated with the four-wave mixing process in atomic rubidium vapor. The low optical power and the excitation wavelengths in the water transparency window have the potential to provide a powerful bio-imaging technique for probing mechanical properties of biological samples prone to phototoxicity and thermal effects. The performance enhancement affordable through the use of quantum light may pave the way for significantly improved sensitivity that cannot be achieved classically. The proposed method for utilizing squeezed light for enhanced stimulated Brillouin scattering can be easily adapted for both spectroscopic and imaging applications in biology.
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Affiliation(s)
- Tian Li
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, Tennessee 37403, USA
| | - Fu Li
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - Xinghua Liu
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - Vladislav V. Yakovlev
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Girish S. Agarwal
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
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19
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Li J, Zhang H, Lu M, Wei H, Li Y. Sensitive impulsive stimulated Brillouin spectroscopy by an adaptive noise-suppression Matrix Pencil. OPTICS EXPRESS 2022; 30:29598-29610. [PMID: 36299131 DOI: 10.1364/oe.465106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/17/2022] [Indexed: 06/16/2023]
Abstract
Impulsive stimulated Brillouin spectroscopy (ISBS) plays a critical role in investigating mechanical properties thanks to its fast measurement rate. However, traditional Fourier transform-based data processing cannot decipher measured data sensitively because of its incompetence in dealing with low signal-to-noise ratio (SNR) signals caused by a short exposure time and weak signals in a multi-peak spectrum. Here, we propose an adaptive noise-suppression Matrix Pencil method for heterodyne ISBS as an alternative spectral analysis technique, speeding up the measurement regardless of the low SNR and enhancing the sensitivity of multi-component viscoelastic identification. The algorithm maintains accuracy of 0.005% for methanol sound speed even when the SNR drops 33 dB and the exposure time is reduced to 0.4 ms. Moreover, it proves to extract a weak component that accounts for 6% from a polymer mixture, which is inaccessible for the traditional method. With its outstanding ability to sensitively decipher weak signals without spectral a priori information and regardless of low SNRs or concentrations, this method offers a fresh perspective for ISBS on fast viscoelasticity measurements and multi-component identifications.
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20
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Light-sheet photonic force optical coherence elastography for high-throughput quantitative 3D micromechanical imaging. Nat Commun 2022; 13:3465. [PMID: 35710790 PMCID: PMC9203576 DOI: 10.1038/s41467-022-30995-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 05/23/2022] [Indexed: 11/09/2022] Open
Abstract
Quantitative characterisation of micro-scale mechanical properties of the extracellular matrix (ECM) and dynamic cell-ECM interactions can significantly enhance fundamental discoveries and their translational potential in the rapidly growing field of mechanobiology. However, quantitative 3D imaging of ECM mechanics with cellular-scale resolution and dynamic monitoring of cell-mediated changes to pericellular viscoelasticity remain a challenge for existing mechanical characterisation methods. Here, we present light-sheet photonic force optical coherence elastography (LS-pfOCE) to address this need by leveraging a light-sheet for parallelised, non-invasive, and localised mechanical loading. We demonstrate the capabilities of LS-pfOCE by imaging the micromechanical heterogeneity of fibrous collagen matrices and perform live-cell imaging of cell-mediated ECM micromechanical dynamics. By providing access to 4D spatiotemporal variations in the micromechanical properties of 3D biopolymer constructs and engineered cellular systems, LS-pfOCE has the potential to drive new discoveries in mechanobiology and contribute to the development of novel biomechanics-based clinical diagnostics and therapies.
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21
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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.
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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
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22
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Maksymov IS, Huy Nguyen BQ, Pototsky A, Suslov S. Acoustic, Phononic, Brillouin Light Scattering and Faraday Wave-Based Frequency Combs: Physical Foundations and Applications. SENSORS (BASEL, SWITZERLAND) 2022; 22:3921. [PMID: 35632330 PMCID: PMC9143010 DOI: 10.3390/s22103921] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/16/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022]
Abstract
Frequency combs (FCs)-spectra containing equidistant coherent peaks-have enabled researchers and engineers to measure the frequencies of complex signals with high precision, thereby revolutionising the areas of sensing, metrology and communications and also benefiting the fundamental science. Although mostly optical FCs have found widespread applications thus far, in general FCs can be generated using waves other than light. Here, we review and summarise recent achievements in the emergent field of acoustic frequency combs (AFCs), including phononic FCs and relevant acousto-optical, Brillouin light scattering and Faraday wave-based techniques that have enabled the development of phonon lasers, quantum computers and advanced vibration sensors. In particular, our discussion is centred around potential applications of AFCs in precision measurements in various physical, chemical and biological systems in conditions where using light, and hence optical FCs, faces technical and fundamental limitations, which is, for example, the case in underwater distance measurements and biomedical imaging applications. This review article will also be of interest to readers seeking a discussion of specific theoretical aspects of different classes of AFCs. To that end, we support the mainstream discussion by the results of our original analysis and numerical simulations that can be used to design the spectra of AFCs generated using oscillations of gas bubbles in liquids, vibrations of liquid drops and plasmonic enhancement of Brillouin light scattering in metal nanostructures. We also discuss the application of non-toxic room-temperature liquid-metal alloys in the field of AFC generation.
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Affiliation(s)
- Ivan S. Maksymov
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122, Australia;
| | - Bui Quoc Huy Nguyen
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122, Australia;
| | - Andrey Pototsky
- Department of Mathematics, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (A.P.); (S.S.)
| | - Sergey Suslov
- Department of Mathematics, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (A.P.); (S.S.)
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23
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The evolving role of the Caenorhabditis elegans model as a tool to advance studies in nutrition and health. Nutr Res 2022; 106:47-59. [DOI: 10.1016/j.nutres.2022.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 12/29/2022]
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24
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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.
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25
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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.
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26
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Kim K, Gade VR, Kurzchalia TV, Guck J. Quantitative imaging of Caenorhabditis elegans dauer larvae during cryptobiotic transition. Biophys J 2022; 121:1219-1229. [PMID: 35192842 PMCID: PMC9034246 DOI: 10.1016/j.bpj.2022.02.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/09/2021] [Accepted: 02/16/2022] [Indexed: 11/02/2022] Open
Abstract
Upon starvation or overcrowding, the nematode Caenorhabditis elegans enters diapause by forming a dauer larva, which can then further survive harsh desiccation in an anhydrobiotic state. We have previously identified the genetic and biochemical pathways essential for survival-but without detailed knowledge of their material properties, the mechanistic understanding of this intriguing phenomenon remains incomplete. Here we employed optical diffraction tomography (ODT) to quantitatively assess the internal mass density distribution of living larvae in the reproductive and diapause stages. ODT revealed that the properties of the dauer larvae undergo a dramatic transition upon harsh desiccation. Moreover, mutants that are sensitive to desiccation displayed structural abnormalities in the anhydrobiotic stage that could not be observed by conventional microscopy. Our advance opens a door to quantitatively assessing the transitions in material properties and structure necessary to fully understand an organism on the verge of life and death.
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27
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Yan G, Monnier S, Mouelhi M, Dehoux T. Probing molecular crowding in compressed tissues with Brillouin light scattering. Proc Natl Acad Sci U S A 2022; 119:e2113614119. [PMID: 35046032 PMCID: PMC8795543 DOI: 10.1073/pnas.2113614119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/13/2021] [Indexed: 12/11/2022] Open
Abstract
Volume regulation is key in maintaining important tissue functions, such as growth or healing. This is achieved by modulation of active contractility as well as water efflux that changes molecular crowding within individual cells. Local sensors have been developed to monitor stresses or forces in model tissues, but these approaches do not capture the contribution of liquid flows to volume regulation. Here, we use a tool based on Brillouin light scattering (BLS) that uses the interaction of a laser light with inherent picosecond timescale density fluctuations in the sample. To investigate volume variations, we induced osmotic perturbations with a polysaccharide osmolyte, Dextran (Dx), and compress cells locally within multicellular spheroids (MCSs). During osmotic compressions, we observe an increase in the BLS frequency shift that reflects local variations in the compressibility. To elucidate these data, we propose a model based on a mixing law that describes the increase of molecular crowding upon reduction of the intracellular fluids. Comparison with the data suggests a nonlinear increase of the compressibility due to the dense crowding that induces hydrodynamic interactions between the cellular polymers.
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Affiliation(s)
- Guqi Yan
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Sylvain Monnier
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Malèke Mouelhi
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Thomas Dehoux
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
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28
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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.
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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
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29
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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.
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30
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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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31
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Rioboó RJJ, Gontán N, Sanderson D, Desco M, Gómez-Gaviro MV. Brillouin Spectroscopy: From Biomedical Research to New Generation Pathology Diagnosis. Int J Mol Sci 2021; 22:8055. [PMID: 34360822 PMCID: PMC8347166 DOI: 10.3390/ijms22158055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/11/2021] [Accepted: 07/23/2021] [Indexed: 01/06/2023] Open
Abstract
Brillouin spectroscopy has recently gained considerable interest within the biomedical field as an innovative tool to study mechanical properties in biology. The Brillouin effect is based on the inelastic scattering of photons caused by their interaction with thermodynamically driven acoustic modes or phonons and it is highly dependent on the material's elasticity. Therefore, Brillouin is a contactless, label-free optic approach to elastic and viscoelastic analysis that has enabled unprecedented analysis of ex vivo and in vivo mechanical behavior of several tissues with a micrometric resolution, paving the way to a promising future in clinical diagnosis. Here, we comprehensively review the different studies of this fast-moving field that have been performed up to date to provide a quick guide of the current literature. In addition, we offer a general view of Brillouin's biomedical potential to encourage its further development to reach its implementation as a feasible, cost-effective pathology diagnostic tool.
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Affiliation(s)
- Rafael J. Jiménez Rioboó
- Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), C/Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain;
| | - Nuria Gontán
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
| | - Daniel Sanderson
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
| | - Manuel Desco
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029 Madrid, Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Maria Victoria Gómez-Gaviro
- Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain; (N.G.); (D.S.)
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, 28911 Madrid, Spain
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32
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Bailey M, Gardner B, Alunni-Cardinali M, Caponi S, Fioretto D, Stone N, Palombo F. Predicting the Refractive Index of Tissue Models Using Light Scattering Spectroscopy. APPLIED SPECTROSCOPY 2021; 75:574-580. [PMID: 33319606 PMCID: PMC8114435 DOI: 10.1177/0003702820984482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
In this work, we report the application of Raman microspectroscopy for analysis of the refractive index of a range of tissue phantoms. Using both a custom-developed setup with visible laser source and a commercial microspectrometer with near infrared laser, we measured the Raman spectra of gelatin hydrogels at various concentrations. By building a calibration curve from measured refractometry data and Raman scattering intensity for different vibrational modes of the hydrogel, we were able to predict the refractive indices of the gels from their Raman spectra. This work highlights the importance of a correlative approach through Brillouin-Raman microspectroscopy for the mechano-chemical analysis of biologically relevant samples.
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Affiliation(s)
- Michelle Bailey
- School of Physics and Astronomy, University of Exeter, Exeter, UK
| | - Benjamin Gardner
- School of Physics and Astronomy, University of Exeter, Exeter, UK
| | | | - Silvia Caponi
- CNR-IOM – Istituto Officina dei Materiali – Research Unit in Perugia, c/o Department of Physics and Geology, University of Perugia, Perugia, Italy
| | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Perugia, Italy
| | - Nick Stone
- School of Physics and Astronomy, University of Exeter, Exeter, UK
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33
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Khalilgharibi N, Mao Y. To form and function: on the role of basement membrane mechanics in tissue development, homeostasis and disease. Open Biol 2021; 11:200360. [PMID: 33593159 PMCID: PMC8061686 DOI: 10.1098/rsob.200360] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The basement membrane (BM) is a special type of extracellular matrix that lines the basal side of epithelial and endothelial tissues. Functionally, the BM is important for providing physical and biochemical cues to the overlying cells, sculpting the tissue into its correct size and shape. In this review, we focus on recent studies that have unveiled the complex mechanical properties of the BM. We discuss how these properties can change during development, homeostasis and disease via different molecular mechanisms, and the subsequent impact on tissue form and function in a variety of organisms. We also explore how better characterization of BM mechanics can contribute to disease diagnosis and treatment, as well as development of better in silico and in vitro models that not only impact the fields of tissue engineering and regenerative medicine, but can also reduce the use of animals in research.
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Affiliation(s)
- Nargess Khalilgharibi
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.,Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK
| | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.,Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK
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34
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Smith RJ, Pérez-Cota F, Marques L, Clark M. 3D phonon microscopy with sub-micron axial-resolution. Sci Rep 2021; 11:3301. [PMID: 33558575 PMCID: PMC7870650 DOI: 10.1038/s41598-021-82639-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/18/2021] [Indexed: 12/12/2022] Open
Abstract
Brillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the instrumentation have enabled imaging of fixed and living cells. This work presents the first experimental characterisation of phonon-based axial resolution provided by the response to a sharp edge. The obtained axial resolution is up to 10 times higher than that of the optical system used to take the measurements. Validation of the results are obtained with various polymer objects, which are in good agreement with those obtained using atomic force microscopy. Edge localisation, and hence profilometry, of a phantom boundary is measured with accuracy and precision of approximately 60 nm and 100 nm respectively. Finally, 3D imaging of fixed cells in culture medium is demonstrated.
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Affiliation(s)
- Richard J Smith
- Optics and Photonics, Faculty of Engineering, University of Nottingham, University Park, Nottingham, UK.
| | - Fernando Pérez-Cota
- Optics and Photonics, Faculty of Engineering, University of Nottingham, University Park, Nottingham, UK
| | - Leonel Marques
- Optics and Photonics, Faculty of Engineering, University of Nottingham, University Park, Nottingham, UK
| | - Matt Clark
- Optics and Photonics, Faculty of Engineering, University of Nottingham, University Park, Nottingham, UK
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35
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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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36
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Bailey M, Alunni-Cardinali M, Correa N, Caponi S, Holsgrove T, Barr H, Stone N, Winlove CP, Fioretto D, Palombo F. Viscoelastic properties of biopolymer hydrogels determined by Brillouin spectroscopy: A probe of tissue micromechanics. SCIENCE ADVANCES 2020; 6:eabc1937. [PMID: 33127678 PMCID: PMC7608813 DOI: 10.1126/sciadv.abc1937] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 09/16/2020] [Indexed: 05/09/2023]
Abstract
Many problems in mechanobiology urgently require characterization of the micromechanical properties of cells and tissues. Brillouin light scattering has been proposed as an emerging optical elastography technique to meet this need. However, the information contained in the Brillouin spectrum is still a matter of debate because of fundamental problems in understanding the role of water in biomechanics and in relating the Brillouin data to low-frequency macroscopic mechanical parameters. Here, we investigate this question using gelatin as a model system in which the macroscopic physical properties can be manipulated to mimic all the relevant biological states of matter, ranging from the liquid to the gel and the glassy phase. We demonstrate that Brillouin spectroscopy is able to reveal both the elastic and viscous properties of biopolymers that are central to the structure and function of biological tissues.
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Affiliation(s)
- Michelle Bailey
- University of Exeter, School of Physics and Astronomy, Exeter EX4 4QL, UK
| | | | - Noemi Correa
- University of Exeter, School of Physics and Astronomy, Exeter EX4 4QL, UK
| | - Silvia Caponi
- CNR-IOM-Istituto Officina dei Materiali-Research Unit in Perugia, Department of Physics and Geology, University of Perugia, Perugia I-06123, Italy
| | | | - Hugh Barr
- Gloucestershire Royal Hospital, Gloucester GL1 3NN, UK
| | - Nick Stone
- University of Exeter, School of Physics and Astronomy, Exeter EX4 4QL, UK
| | - C Peter Winlove
- University of Exeter, School of Physics and Astronomy, Exeter EX4 4QL, UK
| | - Daniele Fioretto
- University of Perugia, Department of Physics and Geology, Perugia I-06123, Italy.
| | - Francesca Palombo
- University of Exeter, School of Physics and Astronomy, Exeter EX4 4QL, UK.
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