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Aydin H, Ozcelikkale A, Acar A. Exploiting Matrix Stiffness to Overcome Drug Resistance. ACS Biomater Sci Eng 2024; 10:4682-4700. [PMID: 38967485 PMCID: PMC11322920 DOI: 10.1021/acsbiomaterials.4c00445] [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: 03/06/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 07/06/2024]
Abstract
Drug resistance is arguably one of the biggest challenges facing cancer research today. Understanding the underlying mechanisms of drug resistance in tumor progression and metastasis are essential in developing better treatment modalities. Given the matrix stiffness affecting the mechanotransduction capabilities of cancer cells, characterization of the related signal transduction pathways can provide a better understanding for developing novel therapeutic strategies. In this review, we aimed to summarize the recent advancements in tumor matrix biology in parallel to therapeutic approaches targeting matrix stiffness and its consequences in cellular processes in tumor progression and metastasis. The cellular processes governed by signal transduction pathways and their aberrant activation may result in activating the epithelial-to-mesenchymal transition, cancer stemness, and autophagy, which can be attributed to drug resistance. Developing therapeutic strategies to target these cellular processes in cancer biology will offer novel therapeutic approaches to tailor better personalized treatment modalities for clinical studies.
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Affiliation(s)
- Hakan
Berk Aydin
- Department
of Biological Sciences, Middle East Technical
University, 06800, Ankara, Turkey
| | - Altug Ozcelikkale
- Department
of Mechanical Engineering, Middle East Technical
University, 06800, Ankara, Turkey
- Graduate
Program of Biomedical Engineering, Middle
East Technical University, 06800, Ankara, Turkey
| | - Ahmet Acar
- Department
of Biological Sciences, Middle East Technical
University, 06800, Ankara, Turkey
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2
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Urbanska M, Guck J. Single-Cell Mechanics: Structural Determinants and Functional Relevance. Annu Rev Biophys 2024; 53:367-395. [PMID: 38382116 DOI: 10.1146/annurev-biophys-030822-030629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
The mechanical phenotype of a cell determines its ability to deform under force and is therefore relevant to cellular functions that require changes in cell shape, such as migration or circulation through the microvasculature. On the practical level, the mechanical phenotype can be used as a global readout of the cell's functional state, a marker for disease diagnostics, or an input for tissue modeling. We focus our review on the current knowledge of structural components that contribute to the determination of the cellular mechanical properties and highlight the physiological processes in which the mechanical phenotype of the cells is of critical relevance. The ongoing efforts to understand how to efficiently measure and control the mechanical properties of cells will define the progress in the field and drive mechanical phenotyping toward clinical applications.
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Affiliation(s)
- Marta Urbanska
- Max Planck Institute for the Science of Light, Erlangen, Germany; ,
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Jochen Guck
- Max Planck Institute for the Science of Light, Erlangen, Germany; ,
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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3
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Seelbinder B, Wagner S, Jain M, Erben E, Klykov S, Stoev ID, Krishnaswamy VR, Kreysing M. Probe-free optical chromatin deformation and measurement of differential mechanical properties in the nucleus. eLife 2024; 13:e76421. [PMID: 38214505 PMCID: PMC10786458 DOI: 10.7554/elife.76421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
The nucleus is highly organized to facilitate coordinated gene transcription. Measuring the rheological properties of the nucleus and its sub-compartments will be crucial to understand the principles underlying nuclear organization. Here, we show that strongly localized temperature gradients (approaching 1°C/µm) can lead to substantial intra-nuclear chromatin displacements (>1 µm), while nuclear area and lamina shape remain unaffected. Using particle image velocimetry (PIV), intra-nuclear displacement fields can be calculated and converted into spatio-temporally resolved maps of various strain components. Using this approach, we show that chromatin displacements are highly reversible, indicating that elastic contributions are dominant in maintaining nuclear organization on the time scale of seconds. In genetically inverted nuclei, centrally compacted heterochromatin displays high resistance to deformation, giving a rigid, solid-like appearance. Correlating spatially resolved strain maps with fluorescent reporters in conventional interphase nuclei reveals that various nuclear compartments possess distinct mechanical identities. Surprisingly, both densely and loosely packed chromatin showed high resistance to deformation, compared to medium dense chromatin. Equally, nucleoli display particularly high resistance and strong local anchoring to heterochromatin. Our results establish how localized temperature gradients can be used to drive nuclear compartments out of mechanical equilibrium to obtain spatial maps of their material responses.
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Affiliation(s)
- Benjamin Seelbinder
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Susan Wagner
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Institute of Biological and Chemical Systems-Biological Information Processing, Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
| | - Manavi Jain
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Elena Erben
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Sergei Klykov
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Iliya Dimitrov Stoev
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | | | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
- Institute of Biological and Chemical Systems-Biological Information Processing, Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
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4
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Martinez-Vidal L, Testi C, Pontecorvo E, Pederzoli F, Alchera E, Locatelli I, Venegoni C, Spinelli A, Lucianò R, Salonia A, Podestà A, Ruocco G, Alfano M. Progressive alteration of murine bladder elasticity in actinic cystitis detected by Brillouin microscopy. Sci Rep 2024; 14:484. [PMID: 38177637 PMCID: PMC10766652 DOI: 10.1038/s41598-023-51006-2] [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: 07/13/2023] [Accepted: 12/29/2023] [Indexed: 01/06/2024] Open
Abstract
Bladder mechanical properties are critical for organ function and tissue homeostasis. Therefore, alterations of tissue mechanics are linked to disease onset and progression. This study aims to characterize the tissue elasticity of the murine bladder wall considering its different anatomical components, both in healthy conditions and in actinic cystitis, a state characterized by tissue fibrosis. Here, we exploit Brillouin microscopy, an emerging technique in the mechanobiology field that allows mapping tissue mechanics at the microscale, in non-contact mode and free of labeling. We show that Brillouin imaging of bladder tissues is able to recognize the different anatomical components of the bladder wall, confirmed by histopathological analysis, showing different tissue mechanical properties of the physiological bladder, as well as a significant alteration in the presence of tissue fibrosis. Our results point out the potential use of Brillouin imaging on clinically relevant samples as a complementary technique to histopathological analysis, deciphering complex mechanical alteration of each tissue layer of an organ that strongly relies on mechanical properties to perform its function.
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Affiliation(s)
- Laura Martinez-Vidal
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy.
- Università Vita-Salute San Raffaele, Via Olgettina, 60, 20132, Milan, Italy.
| | - Claudia Testi
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161, Roma, Italy.
| | - Emanuele Pontecorvo
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161, Roma, Italy
- CrestOptics S.p.A., Via Di Torre Rossa, 66, 00165, Roma, Italy
| | - Filippo Pederzoli
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
- Università Vita-Salute San Raffaele, Via Olgettina, 60, 20132, Milan, Italy
| | - Elisa Alchera
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Irene Locatelli
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Chiara Venegoni
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Antonello Spinelli
- Experimental Imaging Centre, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Roberta Lucianò
- Pathology Unit, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | - Andrea Salonia
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
- Università Vita-Salute San Raffaele, Via Olgettina, 60, 20132, Milan, Italy
| | - Alessandro Podestà
- Dipartimento Di Fisica "Aldo Pontremoli" and CIMAINA, Università Degli Studi Di Milano, 20133, Milan, Italy
| | - Giancarlo Ruocco
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161, Roma, Italy
- Dipartimento Di Fisica, Universitá Di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185, Roma, Italy
| | - Massimo Alfano
- Division of Experimental Oncology/Unit of Urology, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
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5
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Gogoi RP, Galoforo S, Fox A, Morris C, Ramos H, Gogoi VK, Chehade H, Adzibolosu NK, Shi C, Zhang J, Tedja R, Morris R, Alvero AB, Mor G. A Novel Role of Connective Tissue Growth Factor in the Regulation of the Epithelial Phenotype. Cancers (Basel) 2023; 15:4834. [PMID: 37835529 PMCID: PMC10571845 DOI: 10.3390/cancers15194834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/21/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Epithelial-mesenchymal transition (EMT) is a biological process where epithelial cells lose their adhesive properties and gain invasive, metastatic, and mesenchymal properties. Maintaining the balance between the epithelial and mesenchymal stage is essential for tissue homeostasis. Many of the genes promoting mesenchymal transformation have been identified; however, our understanding of the genes responsible for maintaining the epithelial phenotype is limited. Our objective was to identify the genes responsible for maintaining the epithelial phenotype and inhibiting EMT. METHODS RNA seq was performed using an vitro model of EMT. CTGF expression was determined via qPCR and Western blot analysis. The knockout of CTGF was completed using the CTGF sgRNA CRISPR/CAS9. The tumorigenic potential was determined using NCG mice. RESULTS The knockout of CTGF in epithelial ovarian cancer cells leads to the acquisition of functional characteristics associated with the mesenchymal phenotype such as anoikis resistance, cytoskeleton remodeling, increased cell stiffness, and the acquisition of invasion and tumorigenic capacity. CONCLUSIONS We identified CTGF is an important regulator of the epithelial phenotype, and its loss is associated with the early cellular modifications required for EMT. We describe a novel role for CTGF, regulating cytoskeleton and the extracellular matrix interactions necessary for the conservation of epithelial structure and function. These findings provide a new window into understanding the early stages of mesenchymal transformation.
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Affiliation(s)
- Radhika P. Gogoi
- Karmanos Cancer Institute, Wayne State University, 4100 John R St, Detroit, MI 48202, USA;
| | - Sandra Galoforo
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Alexandra Fox
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Colton Morris
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Harry Ramos
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Vir K. Gogoi
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Hussein Chehade
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Nicholas K. Adzibolosu
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Chenjun Shi
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA; (C.S.); (J.Z.)
| | - Jitao Zhang
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA; (C.S.); (J.Z.)
| | - Roslyn Tedja
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Robert Morris
- Karmanos Cancer Institute, Wayne State University, 4100 John R St, Detroit, MI 48202, USA;
| | - Ayesha B. Alvero
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
| | - Gil Mor
- C.S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (S.G.); (A.F.); (C.M.); (H.R.); (V.K.G.); (H.C.); (N.K.A.); (R.T.); (A.B.A.)
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6
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Pang K, Dong S, Zhu Y, Zhu X, Zhou Q, Gu B, Jin W, Zhang R, Fu Y, Yu B, Sun D, Duanmu Z, Wei X. Advanced flow cytometry for biomedical applications. JOURNAL OF BIOPHOTONICS 2023; 16:e202300135. [PMID: 37263969 DOI: 10.1002/jbio.202300135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/03/2023]
Abstract
Flow cytometry (FC) is a versatile tool with excellent capabilities to detect and measure multiple characteristics of a population of cells or particles. Notable advancements in in vivo photoacoustic FC, coherent Raman FC, microfluidic FC, and so on, have been achieved in the last two decades, which endows FC with new functions and expands its applications in basic research and clinical practice. Advanced FC broadens the tools available to researchers to conduct research involving cancer detection, microbiology (COVID-19, HIV, bacteria, etc.), and nucleic acid analysis. This review presents an overall picture of advanced flow cytometers and provides not only a clear understanding of their mechanisms but also new insights into their practical applications. We identify the latest trends in this area and aim to raise awareness of advanced techniques of FC. We hope this review expands the applications of FC and accelerates its clinical translation.
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Affiliation(s)
- Kai Pang
- School of Instrument Science and Opto-Electronics Engineering of Beijing Information Science & Technology University, Beijing, China
| | - Sihan Dong
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China
| | - Yuxi Zhu
- School of Instrument Science and Opto-Electronics Engineering of Beijing Information Science & Technology University, Beijing, China
| | - Xi Zhu
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Quanyu Zhou
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Bobo Gu
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Wei Jin
- International Cancer Institute, Peking University, Beijing, China
| | - Rui Zhang
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China
| | - Yuting Fu
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China
| | - Bingchen Yu
- School of Instrument Science and Opto-Electronics Engineering of Beijing Information Science & Technology University, Beijing, China
| | - Da Sun
- School of Instrument Science and Opto-Electronics Engineering of Beijing Information Science & Technology University, Beijing, China
| | - Zheng Duanmu
- School of Instrument Science and Opto-Electronics Engineering of Beijing Information Science & Technology University, Beijing, China
| | - Xunbin Wei
- International Cancer Institute, Peking University, Beijing, China
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7
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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] [MESH Headings] [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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8
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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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9
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Siu DMD, Lee KCM, Chung BMF, Wong JSJ, Zheng G, Tsia KK. Optofluidic imaging meets deep learning: from merging to emerging. LAB ON A CHIP 2023; 23:1011-1033. [PMID: 36601812 DOI: 10.1039/d2lc00813k] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Propelled by the striking advances in optical microscopy and deep learning (DL), the role of imaging in lab-on-a-chip has dramatically been transformed from a silo inspection tool to a quantitative "smart" engine. A suite of advanced optical microscopes now enables imaging over a range of spatial scales (from molecules to organisms) and temporal window (from microseconds to hours). On the other hand, the staggering diversity of DL algorithms has revolutionized image processing and analysis at the scale and complexity that were once inconceivable. Recognizing these exciting but overwhelming developments, we provide a timely review of their latest trends in the context of lab-on-a-chip imaging, or coined optofluidic imaging. More importantly, here we discuss the strengths and caveats of how to adopt, reinvent, and integrate these imaging techniques and DL algorithms in order to tailor different lab-on-a-chip applications. In particular, we highlight three areas where the latest advances in lab-on-a-chip imaging and DL can form unique synergisms: image formation, image analytics and intelligent image-guided autonomous lab-on-a-chip. Despite the on-going challenges, we anticipate that they will represent the next frontiers in lab-on-a-chip imaging that will spearhead new capabilities in advancing analytical chemistry research, accelerating biological discovery, and empowering new intelligent clinical applications.
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Affiliation(s)
- Dickson M D Siu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
| | - Kelvin C M Lee
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
| | - Bob M F Chung
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Justin S J Wong
- Conzeb Limited, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Guoan Zheng
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA
| | - Kevin K Tsia
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
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10
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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.
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11
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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.
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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.
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12
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Liu L, Simon M, Muggiolu G, Vilotte F, Antoine M, Caron J, Kantor G, Barberet P, Seznec H, Audoin B. Changes in intra-nuclear mechanics in response to DNA damaging agents revealed by time-domain Brillouin micro-spectroscopy. PHOTOACOUSTICS 2022; 27:100385. [PMID: 36068801 PMCID: PMC9441258 DOI: 10.1016/j.pacs.2022.100385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 05/25/2023]
Abstract
How DNA damage and repair processes affect the biomechanical properties of the nucleus interior remains unknown. Here, an opto-acoustic microscope based on time-domain Brillouin spectroscopy (TDBS) was used to investigate the induced regulation of intra-nuclear mechanics. With this ultrafast pump-probe technique, coherent acoustic phonons were tracked along their propagation in the intra-nucleus nanostructure and the complex stiffness moduli and thicknesses were measured with an optical resolution. Osteosarcoma cells were exposed to methyl methanesulfonate (MMS) and the presence of DNA damage was tested using immunodetection targeted against damage signaling proteins. TDBS revealed that the intra-nuclear storage modulus decreased significantly upon exposure to MMS, as a result of the chromatin decondensation and reorganization that favors molecular diffusion within the organelle. When the damaging agent was removed and cells incubated for 2 h in the buffer solution before fixation the intra-nuclear reorganization led to an inverse evolution of the storage modulus, the nucleus stiffened. The same tendency was measured when DNA double-strand breaks were caused by cell exposure to ionizing radiation. TDBS microscopy also revealed changes in acoustic dissipation, another mechanical probe of the intra-nucleus organization at the nano-scale, and changes in nucleus thickness during exposure to MMS and after recovery.
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Affiliation(s)
- Liwang Liu
- Univ. Bordeaux, CNRS, I2M, UMR 5295, F-33400 Talence, France
| | - Marina Simon
- Univ. Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
| | | | - Florent Vilotte
- Univ. Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | - Mikael Antoine
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | - Jerôme Caron
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | - Guy Kantor
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | | | - Hervé Seznec
- Univ. Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
| | - Bertrand Audoin
- Univ. Bordeaux, CNRS, I2M, UMR 5295, F-33400 Talence, France
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13
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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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14
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Rix J, Uckermann O, Kirsche K, Schackert G, Koch E, Kirsch M, Galli R. Correlation of biomechanics and cancer cell phenotype by combined Brillouin and Raman spectroscopy of U87-MG glioblastoma cells. JOURNAL OF THE ROYAL SOCIETY, INTERFACE 2022; 19:20220209. [PMID: 35857926 DOI: 10.1098/rsif.2022.0209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The elucidation of biomechanics furthers our understanding of brain tumour biology. Brillouin spectroscopy is a new optical method that addresses viscoelastic properties down to subcellular resolution in a contact-free manner. Moreover, it can be combined with Raman spectroscopy to obtain co-localized biochemical information. Here, we applied co-registered Brillouin and Raman spectroscopy to U87-MG human glioblastoma cells in vitro. Using two-dimensional and three-dimensional cultures, we related biomechanical properties to local biochemical composition at the subcellular level, as well as the cell phenotype. Brillouin and Raman mapping of adherent cells showed that the nucleus and nucleoli are stiffer than the perinuclear region and the cytoplasm. The biomechanics of the cell cytoplasm is affected by culturing conditions, i.e. cells grown as spheroids are stiffer than adherent cells. Inside the spheroids, the presence of lipid droplets as assessed by Raman spectroscopy revealed higher Brillouin shifts that are not related to a local increase in stiffness, but are due to a higher refractive index combined with a lower mass density. This highlights the importance of locally defined biochemical reference data for a correct interpretation of the Brillouin shift of cells and tissues in future studies investigating the biomechanics of brain tumour models by Brillouin spectroscopy.
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Affiliation(s)
- Jan Rix
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Ortrud Uckermann
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany.,Division of Medical Biology, Department of Psychiatry, Faculty of Medicine and University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Katrin Kirsche
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Gabriele Schackert
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Edmund Koch
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Matthias Kirsch
- Neurosurgery, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany.,Klinik für Neurochirurgie, Asklepios Kliniken Schildautal, Karl-Herold-Strasse 1, D-38723 Seesen, Germany.,National Center for Tumor Diseases (NCT), Partner Site Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
| | - Roberta Galli
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany
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15
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Zhang Y, Zhao Y, Cole T, Zheng J, Bayinqiaoge, Guo J, Tang SY. Microfluidic flow cytometry for blood-based biomarker analysis. Analyst 2022; 147:2895-2917. [PMID: 35611964 DOI: 10.1039/d2an00283c] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Flow cytometry has proven its capability for rapid and quantitative analysis of individual cells and the separation of targeted biological samples from others. The emerging microfluidics technology makes it possible to develop portable microfluidic diagnostic devices for point-of-care testing (POCT) applications. Microfluidic flow cytometry (MFCM), where flow cytometry and microfluidics are combined to achieve similar or even superior functionalities on microfluidic chips, provides a powerful single-cell characterisation and sorting tool for various biological samples. In recent years, researchers have made great progress in the development of the MFCM including focusing, detecting, and sorting subsystems, and its unique capabilities have been demonstrated in various biological applications. Moreover, liquid biopsy using blood can provide various physiological and pathological information. Thus, biomarkers from blood are regarded as meaningful circulating transporters of signal molecules or particles and have great potential to be used as non (or minimally)-invasive diagnostic tools. In this review, we summarise the recent progress of the key subsystems for MFCM and its achievements in blood-based biomarker analysis. Finally, foresight is offered to highlight the research challenges faced by MFCM in expanding into blood-based POCT applications, potentially yielding commercialisation opportunities.
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Affiliation(s)
- Yuxin Zhang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Ying Zhao
- National Chengdu Centre of Safety Evaluation of Drugs, West China Hospital of Sichuan University, Chengdu, China
| | - Tim Cole
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Jiahao Zheng
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Bayinqiaoge
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Jinhong Guo
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, #1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, China.
| | - Shi-Yang Tang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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16
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Amini R, Bhatnagar A, Schlüßler R, Möllmert S, Guck J, Norden C. Amoeboid-like migration ensures correct horizontal cell layer formation in the developing vertebrate retina. eLife 2022; 11:76408. [PMID: 35639083 PMCID: PMC9208757 DOI: 10.7554/elife.76408] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
Migration of cells in the developing brain is integral for the establishment of neural circuits and function of the central nervous system. While migration modes during which neurons employ predetermined directional guidance of either preexisting neuronal processes or underlying cells have been well explored, less is known about how cells featuring multipolar morphology migrate in the dense environment of the developing brain. To address this, we here investigated multipolar migration of horizontal cells in the zebrafish retina. We found that these cells feature several hallmarks of amoeboid-like migration that enable them to tailor their movements to the spatial constraints of the crowded retina. These hallmarks include cell and nuclear shape changes, as well as persistent rearward polarization of stable F-actin. Interference with the organization of the developing retina by changing nuclear properties or overall tissue architecture hampers efficient horizontal cell migration and layer formation showing that cell-tissue interplay is crucial for this process. In view of the high proportion of multipolar migration phenomena observed in brain development, the here uncovered amoeboid-like migration mode might be conserved in other areas of the developing nervous system.
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Affiliation(s)
- Rana Amini
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Archit Bhatnagar
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Raimund Schlüßler
- Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | | | - Jochen Guck
- Max Planck Institute for the Science of Light, Erlangen, Germany
| | - Caren Norden
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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17
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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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18
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Non-contact elastography methods in mechanobiology: a point of view. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 51:99-104. [PMID: 34463775 PMCID: PMC8964566 DOI: 10.1007/s00249-021-01567-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 02/06/2023]
Abstract
In recent decades, mechanobiology has emerged as a novel perspective in the context of basic biomedical research. It is now widely recognized that living cells respond not only to chemical stimuli (for example drugs), but they are also able to decipher mechanical cues, such as the rigidity of the underlying matrix or the presence of shear forces. Probing the viscoelastic properties of cells and their local microenvironment with sub-micrometer resolution is required to study this complex interplay and dig deeper into the mechanobiology of single cells. Current approaches to measure mechanical properties of adherent cells mainly rely on the exploitation of miniaturized indenters, to poke single cells while measuring the corresponding deformation. This method provides a neat implementation of the everyday approach to measure mechanical properties of a material, but it typically results in a very low throughput and invasive experimental protocol, poorly translatable towards three-dimensional living tissues and biological constructs. To overcome the main limitations of nanoindentation experiments, a radical paradigm change is foreseen, adopting next generation contact-less methods to measure mechanical properties of biological samples with sub-cell resolution. Here we briefly introduce the field of single cell mechanical characterization, and we concentrate on a promising high resolution optical elastography technique, Brillouin spectroscopy. This non-contact technique is rapidly emerging as a potential breakthrough innovation in biomechanics, but the application to single cells is still in its infancy.
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19
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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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20
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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.
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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.
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21
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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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22
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Yan G, Bazir A, Margueritat J, Dehoux T. Evaluation of commercial virtually imaged phase array and Fabry-Pérot based Brillouin spectrometers for applications to biology. BIOMEDICAL OPTICS EXPRESS 2020; 11:6933-6944. [PMID: 33408971 PMCID: PMC7747923 DOI: 10.1364/boe.401087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 06/12/2023]
Abstract
Measuring the complex mechanical properties of biological objects has become a necessity to answer key questions in mechanobiology and to propose innovative clinical and therapeutic strategies. In this context, Brillouin light scattering (BLS) has recently come into vogue, offering quantitative imaging of the mechanical properties without labels and with a micrometer resolution. In biological samples, the magnitude of the spectral changes are typically of a few tens of MHz, and the ability of modern spectrometers to monitor such subtle changes needs to be evaluated. Moreover, the multiplicity of variations in optical arrangements, specific to each lab, requires to set a standard for the assessment of the characteristics of BLS systems. In this paper we propose a protocol to evaluate the precision and accuracy of two commercial spectrometers that is reproducible across labs. For a meaningful comparison, we coupled the spectrometers to the same microscope and to the same laser. We first evaluated the optimum acquisition time and laser power. We evaluated the precision using pure water samples. We determined the accuracy by probing water solutions with increasing concentration of salt and comparing it with theory. Following these quantifications, we applied the VIPA-based spectrometer to tumor spheroids engineered from different cell lines that possess different metastatic potentials and resistance to therapies. On these models, we detected significant changes in the linewidth suggesting that BLS measurements of the viscosity could be used as a read-out to distinguish different levels of drug resistance.
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23
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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.
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24
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Mohan A, Gupta P, Nair AP, Prabhakar A, Saiyed T. A microfluidic flow analyzer with integrated lensed optical fibers. BIOMICROFLUIDICS 2020; 14:054104. [PMID: 33062113 PMCID: PMC7532020 DOI: 10.1063/5.0013250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Rapid optical interrogation of flowing cells or particles is a powerful tool in the field of biomedical diagnostics. Determination of size and composition of fast-flowing cells, with diameters in the range of 2- 15 μ m , often require complex open-space optics and expensive high-speed cameras. In this work, a method to overcome these challenges by using a hydrodynamic flow-based microfluidic platform coupled with on-chip integrated fiber optics is reported. The lab-scale portable device developed uses a combination of on-chip lensed and non-lensed optical fibers for precision illumination. The narrow light beam produced by the lensed fiber ( f = 150 μ m ) enables precise optical analysis with high sensitivity. A planar arrangement of optical fibers at various angles facilitates multi-parametric analysis from a single point of interrogation. As proof of concept, the laboratory-scale portable bench-top prototype is used to measure fluorescence signals from CD4 immunostained cells and human blood samples. The performance of microfluidic flow analyzer is also compared to the conventional Guava® easyCyte 8HT flow cytometer.
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Affiliation(s)
- A Mohan
- Department of Electrical Engineering, Indian Institute of Technology Madras (IITM), Chennai 600036, India
| | - P Gupta
- Discovery Innovation Accelerator, Centre for Cellular and Molecular Platforms (C-CAMP), Bengaluru 560065, India
| | - A P Nair
- Discovery Innovation Accelerator, Centre for Cellular and Molecular Platforms (C-CAMP), Bengaluru 560065, India
| | - A Prabhakar
- Department of Electrical Engineering, Indian Institute of Technology Madras (IITM), Chennai 600036, India
| | - T Saiyed
- Discovery Innovation Accelerator, Centre for Cellular and Molecular Platforms (C-CAMP), Bengaluru 560065, India
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25
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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.
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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
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26
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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.
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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
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27
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Song Y, Soto J, Chen B, Yang L, Li S. Cell engineering: Biophysical regulation of the nucleus. Biomaterials 2020; 234:119743. [PMID: 31962231 DOI: 10.1016/j.biomaterials.2019.119743] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/02/2019] [Accepted: 12/25/2019] [Indexed: 12/12/2022]
Abstract
Cells live in a complex and dynamic microenvironment, and a variety of microenvironmental cues can regulate cell behavior. In addition to biochemical signals, biophysical cues can induce not only immediate intracellular responses, but also long-term effects on phenotypic changes such as stem cell differentiation, immune cell activation and somatic cell reprogramming. Cells respond to mechanical stimuli via an outside-in and inside-out feedback loop, and the cell nucleus plays an important role in this process. The mechanical properties of the nucleus can directly or indirectly modulate mechanotransduction, and the physical coupling of the cell nucleus with the cytoskeleton can affect chromatin structure and regulate the epigenetic state, gene expression and cell function. In this review, we will highlight the recent progress in nuclear biomechanics and mechanobiology in the context of cell engineering, tissue remodeling and disease development.
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Affiliation(s)
- Yang Song
- Department of Bioengineering, University of California, Los Angeles, CA, USA; School of Bioengineering, Chongqing University, Chongqing, 400044, China
| | - Jennifer Soto
- Department of Bioengineering, University of California, Los Angeles, CA, USA
| | - Binru Chen
- Department of Bioengineering, University of California, Los Angeles, CA, USA
| | - Li Yang
- School of Bioengineering, Chongqing University, Chongqing, 400044, China
| | - Song Li
- Department of Bioengineering, University of California, Los Angeles, CA, USA; Department of Medicine, University of California, Los Angeles, CA, USA.
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28
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Adichtchev SV, Karpegina YA, Okotrub KA, Surovtseva MA, Zykova VA, Surovtsev NV. Brillouin spectroscopy of biorelevant fluids in relation to viscosity and solute concentration. Phys Rev E 2019; 99:062410. [PMID: 31330595 DOI: 10.1103/physreve.99.062410] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Indexed: 01/11/2023]
Abstract
The measurement of intracellular viscoelastic properties by Brillouin scattering is a rapidly developing field in biophysics and medicine. Here, the Brillouin spectroscopy is applied for a number of aqueous solutions of biorelevant molecules to reveal relations between the Brillouin line parameters (frequency and width) and viscosity or solute concentration. It is found that for the majority of the studied biorelevant molecules the solute concentration governs the Brillouin frequency in a universal manner. On the other hand, the relations between the macroscopic viscosity and Brillouin peak parameters are different for different solutes. We conclude that for biological fluids the viscosity evaluation from Brillouin data needs prior knowledge about the chemical composition. This result challenges the fidelity of the indirect experimental determinations of the cellular viscosity, when small molecule solutions are used for the calibration.
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Affiliation(s)
- S V Adichtchev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Yu A Karpegina
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - K A Okotrub
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - M A Surovtseva
- Research Institute of Clinical and Experimental Lymphology-Branch of Institute of Cytology and Genetics, Russian Academy of Sciences, 630060 Novosibirsk, Russia
| | - V A Zykova
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - N V Surovtsev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
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29
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Davidson PM, Fedorchak GR, Mondésert-Deveraux S, Bell ES, Isermann P, Aubry D, Allena R, Lammerding J. High-throughput microfluidic micropipette aspiration device to probe time-scale dependent nuclear mechanics in intact cells. LAB ON A CHIP 2019; 19:3652-3663. [PMID: 31559980 PMCID: PMC6810812 DOI: 10.1039/c9lc00444k] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The mechanical properties of the cell nucleus are increasingly recognized as critical in many biological processes. The deformability of the nucleus determines the ability of immune and cancer cells to migrate through tissues and across endothelial cell layers, and changes to the mechanical properties of the nucleus can serve as novel biomarkers in processes such as cancer progression and stem cell differentiation. However, current techniques to measure the viscoelastic nuclear mechanical properties are often time consuming, limited to probing one cell at a time, or require expensive, highly specialized equipment. Furthermore, many current assays do not measure time-dependent properties, which are characteristic of viscoelastic materials. Here, we present an easy-to-use microfluidic device that applies the well-established approach of micropipette aspiration, adapted to measure many cells in parallel. The device design allows rapid loading and purging of cells for measurements, and minimizes clogging by large particles or clusters of cells. Combined with a semi-automated image analysis pipeline, the microfluidic device approach enables significantly increased experimental throughput. We validated the experimental platform by comparing computational models of the fluid mechanics in the device with experimental measurements of fluid flow. In addition, we conducted experiments on cells lacking the nuclear envelope protein lamin A/C and wild-type controls, which have well-characterized nuclear mechanical properties. Fitting time-dependent nuclear deformation data to power law and different viscoelastic models revealed that loss of lamin A/C significantly altered the elastic and viscous properties of the nucleus, resulting in substantially increased nuclear deformability. Lastly, to demonstrate the versatility of the devices, we characterized the viscoelastic nuclear mechanical properties in a variety of cell lines and experimental model systems, including human skin fibroblasts from an individual with a mutation in the lamin gene associated with dilated cardiomyopathy, healthy control fibroblasts, induced pluripotent stem cells (iPSCs), and human tumor cells. Taken together, these experiments demonstrate the ability of the microfluidic device and automated image analysis platform to provide robust, high throughput measurements of nuclear mechanical properties, including time-dependent elastic and viscous behavior, in a broad range of applications.
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Affiliation(s)
- Patricia M Davidson
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA. and Laboratoire Physico-Chimie Curie, Institut Curie, CNRS UMR 168, Université Paris Science et Lettres, Sorbonne Université, France
| | - Gregory R Fedorchak
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
| | | | - Emily S Bell
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
| | - Philipp Isermann
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
| | - Denis Aubry
- Laboratoire MSSMat UMR CNRS 8579, CentraleSupelec, Université Paris-Saclay, France
| | - Rachele Allena
- Arts et Metiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, France
| | - Jan Lammerding
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
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30
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Abstract
Brillouin spectroscopy and imaging are emerging techniques in analytical science, biophotonics, and biomedicine. They are based on Brillouin light scattering from acoustic waves or phonons in the GHz range, providing a nondestructive contactless probe of the mechanics on a microscale. Novel approaches and applications of these techniques to the field of biomedical sciences are discussed, highlighting the theoretical foundations and experimental methods that have been developed to date. Acknowledging that this is a fast moving field, a comprehensive account of the relevant literature is critically assessed here.
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Affiliation(s)
- Francesca Palombo
- School
of Physics and Astronomy, University of
Exeter, Stocker Road, EX4 4QL Exeter, U.K.
| | - Daniele Fioretto
- Department
of Physics and Geology, University of Perugia, via Alessandro Pascoli, I-06123 Perugia, Italy
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31
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Arandian A, Bagheri Z, Ehtesabi H, Najafi Nobar S, Aminoroaya N, Samimi A, Latifi H. Optical Imaging Approaches to Monitor Static and Dynamic Cell-on-Chip Platforms: A Tutorial Review. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900737. [PMID: 31087503 DOI: 10.1002/smll.201900737] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 04/14/2019] [Indexed: 06/09/2023]
Abstract
Miniaturized laboratories on chip platforms play an important role in handling life sciences studies. The platforms may contain static or dynamic biological cells. Examples are a fixed medium of an organ-on-a-chip and individual cells moving in a microfluidic channel, respectively. Due to feasibility of control or investigation and ethical implications of live targets, both static and dynamic cell-on-chip platforms promise various applications in biology. To extract necessary information from the experiments, the demand for direct monitoring is rapidly increasing. Among different microscopy methods, optical imaging is a straightforward choice. Considering light interaction with biological agents, imaging signals may be generated as a result of scattering or emission effects from a sample. Thus, optical imaging techniques could be categorized into scattering-based and emission-based techniques. In this review, various optical imaging approaches used in monitoring static and dynamic platforms are introduced along with their optical systems, advantages, challenges, and applications. This review may help biologists to find a suitable imaging technique for different cell-on-chip studies and might also be useful for the people who are going to develop optical imaging systems in life sciences studies.
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Affiliation(s)
- Alireza Arandian
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Zeinab Bagheri
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Hamide Ehtesabi
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Shima Najafi Nobar
- Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, 1969764499, Iran
| | - Neda Aminoroaya
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Ashkan Samimi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Hamid Latifi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
- Department of Physics, Shahid Beheshti University, Tehran, 1983969411, Iran
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32
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Conrad C, Gray KM, Stroka KM, Rizvi I, Scarcelli G. Mechanical Characterization of 3D Ovarian Cancer Nodules Using Brillouin Confocal Microscopy. Cell Mol Bioeng 2019; 12:215-226. [PMID: 31719911 DOI: 10.1007/s12195-019-00570-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 04/13/2019] [Indexed: 12/22/2022] Open
Abstract
Introduction The mechanical interaction between cells and their microenvironment is emerging as an important determinant of cancer progression and sensitivity to treatment, including in ovarian cancer (OvCa). However, current technologies limit mechanical analysis in 3D culture systems. Brillouin Confocal Microscopy is an optical non-contact method to assess the mechanical properties of biological materials. Here, we validate the ability of this technology to assess the mechanical properties of 3D tumor nodules. Methods OvCa cells were cultured in 3D using two established methods: (1) overlay cultures on Matrigel; (2) spheroids in ultra-low attachment plates. To alter the mechanical state of these tumors, nodules were immersed in PBS with varying levels of sucrose to induce osmotic stress. Next, nodule mechanical properties were measured by Brillouin microscopy and validated with standard stress-strain tests: Atomic Force Microscopy (AFM) and a parallel plate compression device (Microsquisher). Finally, the nodules were treated with a chemotherapeutic commonly used to manage OvCa, carboplatin, to determine treatment-induced effects on tumor mechanical properties. Results Brillouin microscopy allows mechanical analysis with limited penetration depth (~ 92 µm for Matrigel method; ~ 54 µm for low attachment method). Brillouin microscopy metrics displayed the same trends as the corresponding "gold-standard" Young's moduli measured with stress-strain methods when the osmolality of the medium was increased. Nodules treated with carboplatin showed a decrease in Brillouin frequency shift. Conclusion This validation study paves the way to evaluate the mechanics of 3D nodules, with micron-scale three-dimensional resolution and without contact, thus extending the experimental possibilities.
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Affiliation(s)
- Christina Conrad
- Fischell Department of Bioengineering, University of Maryland, 4228 A. James Clark Hall, College Park, MD 20742 USA
| | - Kelsey M Gray
- Fischell Department of Bioengineering, University of Maryland, 4228 A. James Clark Hall, College Park, MD 20742 USA
| | - Kimberly M Stroka
- Fischell Department of Bioengineering, University of Maryland, 4228 A. James Clark Hall, College Park, MD 20742 USA
| | - Imran Rizvi
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599 USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, 4228 A. James Clark Hall, College Park, MD 20742 USA
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33
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Gouveia RM, Lepert G, Gupta S, Mohan RR, Paterson C, Connon CJ. Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation. Nat Commun 2019; 10:1496. [PMID: 30944320 PMCID: PMC6447573 DOI: 10.1038/s41467-019-09331-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 03/01/2019] [Indexed: 12/13/2022] Open
Abstract
Whilst demonstrated extensively in vitro, the control of cell behaviour via modulation of substrate compliance in live tissues has not been accomplished to date. Here we propose that stem cells can be regulated solely through in situ modulation of tissue biomechanics. By first establishing, via high-resolution Brillouin spectro-microscopy, that the outer edge (limbus) of live human corneas has a substantially lower bulk modulus compared to their centre, we then demonstrate that this difference is associated with limbal epithelial stem cell (LESC) residence and YAP-dependent mechanotransduction. This phenotype-through-biomechanics correlation is further explored in vivo using a rabbit alkali burn model. Specifically, we show that treating the burnt surface of the cornea with collagenase effectively restores the tissue's mechanical properties and its capacity to support LESCs through mechanisms involving YAP suppression. Overall, these findings have extended implications for understanding stem cell niche biomechanics and its impact on tissue regeneration.
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Affiliation(s)
- Ricardo M Gouveia
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle-upon-Tyne, NE1 3BZ, UK
| | - Guillaume Lepert
- The Blackett Laboratory, Imperial College London, London, SW7 2BW, UK
| | - Suneel Gupta
- Harry S. Truman Memorial Veterans Hospital, Columbia, MO 65201, MO, USA
- College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, MO, USA
| | - Rajiv R Mohan
- Harry S. Truman Memorial Veterans Hospital, Columbia, MO 65201, MO, USA
- College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, MO, USA
| | - Carl Paterson
- The Blackett Laboratory, Imperial College London, London, SW7 2BW, UK
| | - Che J Connon
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle-upon-Tyne, NE1 3BZ, UK.
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34
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Nikolić M, Scarcelli G. Long-term Brillouin imaging of live cells with reduced absorption-mediated damage at 660 nm wavelength. BIOMEDICAL OPTICS EXPRESS 2019; 10:1567-1580. [PMID: 31086695 PMCID: PMC6484981 DOI: 10.1364/boe.10.001567] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 05/18/2023]
Abstract
In Brillouin microscopy, absorption-induced photodamage of incident light is the primary limitation on signal-to-noise ratio in many practical scenarios. Here we show that 660 nm may represent an optimal wavelength for Brillouin microscopy as it offers minimal absorption-mediated photodamage at high Brillouin scattering efficiency and the possibility to use a pure and narrow laser line from solid-state lasing medium. We demonstrate that live cells are ~80 times less susceptible to the 660 nm incident light compared to 532 nm light, which overall allows Brillouin imaging of up to more than 30 times higher SNR. We show that this improvement enables Brillouin imaging of live biological samples with improved accuracy, higher speed and/or larger fields of views with denser sampling.
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Affiliation(s)
- Miloš Nikolić
- Maryland Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - Giuliano Scarcelli
- Maryland Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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35
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Fiore A, Bevilacqua C, Scarcelli G. Direct Three-Dimensional Measurement of Refractive Index via Dual Photon-Phonon Scattering. PHYSICAL REVIEW LETTERS 2019; 122:103901. [PMID: 30932682 PMCID: PMC6530466 DOI: 10.1103/physrevlett.122.103901] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Indexed: 05/06/2023]
Abstract
We developed a microscopy technique that can measure the local refractive index without sampling the optical phase delay of the electromagnetic radiation. To do this, we designed and experimentally demonstrated a setup with two colocalized Brillouin scattering interactions that couple to a common acoustic phonon axis; in this scenario, the ratio of Brillouin frequency shifts depends on the refractive index, but not on any other mechanical and/or optical properties of the sample. Integrating the spectral measurement within a confocal microscope, the refractive index is mapped at micron-scale three-dimensional resolution. As the refractive index is probed in epidetection and without assumptions on the geometrical dimensions of the sample, this method may prove useful to characterize biological cells and tissues.
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Affiliation(s)
- Antonio Fiore
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Carlo Bevilacqua
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari, I-70126 Bari, Italy
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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36
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Wu Y, Stewart AG, Lee PVS. On-chip cell mechanophenotyping using phase modulated surface acoustic wave. BIOMICROFLUIDICS 2019; 13:024107. [PMID: 31065306 PMCID: PMC6478592 DOI: 10.1063/1.5084297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/09/2019] [Indexed: 05/05/2023]
Abstract
A surface acoustic wave (SAW) microfluidic chip was designed to measure the compressibility of cells and to differentiate cell mechanophenotypes. Polystyrene microbeads and poly(methylmethacrylate) (PMMA) microbeads were first tested in order to calibrate and validate the acoustic field. We observed the prefocused microbeads being pushed into the new pressure node upon phase shift. The captured trajectory matched well with the equation describing acoustic radiation force. The compressibility of polystyrene microbeads and that of PMMA microbeads was calculated, respectively, by fitting the trajectory from the experiment and that simulated by the equation across a range of compressibility values. Following, A549 human alveolar basal epithelial cells (A549 cells), human airway smooth muscle (HASM) cells, and MCF-7 breast cancer cells were tested using the same procedure. The compressibility of each cell from the three cell types was measured also by fitting trajectories between the experiment and that from the equation; the size was measured by image analysis. A549 cells were more compressible than HASM and MCF-7 cells; HASM cells could be further distinguished from MCF-7 cells by cell size. In addition, MCF-7 cells were treated by colchicine and 2-methoxyestradiol to disrupt the cell microtubules and were found to be more compressible. Computer simulation was also carried out to investigate the effect of cell compressibility and cell size due to acoustic radiation force to examine the sensitivity of the measurement. The SAW microfluidic method is capable of differentiating cell types or cells under different conditions based on the cell compressibility and the cell size.
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Affiliation(s)
- Yanqi Wu
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Alastair G. Stewart
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Peter V. S. Lee
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia
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Fiore A, Scarcelli G. Single etalon design for two-stage cross-axis VIPA spectroscopy. BIOMEDICAL OPTICS EXPRESS 2019; 10:1475-1481. [PMID: 30891361 PMCID: PMC6420281 DOI: 10.1364/boe.10.001475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 05/15/2023]
Abstract
Two-stage cross axis VIPA spectrometers have been widely used in Brillouin microscopy since they provide single shot spectral measurements at high throughput and extinction. However, this spectrometer configuration presents challenges such as size, cost and alignment difficulties between the two cascaded etalons. Here, we present a cross-axis VIPA spectrometer that implements a single etalon, using a light recirculation architecture to achieve the multistage configuration.
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Affiliation(s)
- Antonio Fiore
- Fischell Department of Bioengineering, University of Maryland, 8278 Paint Branch Drive, College Park, MD 20742, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, 8278 Paint Branch Drive, College Park, MD 20742, USA
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38
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Matellan C, Del Río Hernández AE. Where No Hand Has Gone Before: Probing Mechanobiology at the Cellular Level. ACS Biomater Sci Eng 2018; 5:3703-3719. [PMID: 33405886 DOI: 10.1021/acsbiomaterials.8b01206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Physical forces and other mechanical stimuli are fundamental regulators of cell behavior and function. Cells are also biomechanically competent: they generate forces to migrate, contract, remodel, and sense their environment. As the knowledge of the mechanisms of mechanobiology increases, the need to resolve and probe increasingly small scales calls for novel technologies to mechanically manipulate cells, examine forces exerted by cells, and characterize cellular biomechanics. Here, we review novel methods to quantify cellular force generation, measure cell mechanical properties, and exert localized piconewton and nanonewton forces on cells, receptors, and proteins. The combination of these technologies will provide further insight on the effect of mechanical stimuli on cells and the mechanisms that convert these stimuli into biochemical and biomechanical activity.
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Affiliation(s)
- Carlos Matellan
- Cellular and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Armando E Del Río Hernández
- Cellular and Molecular Biomechanics Laboratory, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
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39
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Noninvasive Imaging: Brillouin Confocal Microscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1092:351-364. [DOI: 10.1007/978-3-319-95294-9_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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40
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Zhang J, Raghunathan R, Rippy J, Wu C, Finnell RH, Larin KV, Scarcelli G. Tissue biomechanics during cranial neural tube closure measured by Brillouin microscopy and optical coherence tomography. Birth Defects Res 2018; 111:991-998. [PMID: 30239173 DOI: 10.1002/bdr2.1389] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/03/2018] [Accepted: 08/02/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Embryonic development involves the interplay of driving forces that shape the tissue and the mechanical resistance that the tissue offers in response. While increasing evidence has suggested the crucial role of physical mechanisms underlying embryo development, tissue biomechanics is not well understood because of the lack of techniques that can quantify the stiffness of tissue in situ with 3D high-resolution and in a noncontact manner. METHODS We used two all-optical techniques, optical coherence tomography (OCT) and Brillouin microscopy, to map the longitudinal modulus of the tissue from mouse embryos in situ. RESULTS We acquired 2D mechanical maps of the neural tube region of embryos at embryonic day (E) 8.5 (n = 2) and E9.5 (n = 2) with submicron spatial resolution. We found the modulus of tissue varied distinctly within the neural tube region of the same embryo and between embryos at different development stages, suggesting our technique has enough sensitivity and spatial resolution to monitor the tissue mechanics during embryonic development in a noncontact and noninvasive manner. CONCLUSIONS We demonstrated the capability of OCT-guided Brillouin microscopy to quantify tissue longitudinal modulus of mouse embryos in situ, and observed distinct change in the modulus during the closure of cranial neural tube. Although this preliminary work cannot provide definitive conclusions on biomechanics of neural tube closure yet as a result of the limited number of samples, it provides an approach of quantifying the tissue mechanics during embryo development in situ, thus could be helpful in investigating the role of tissue biomechanics in the regulation of embryonic development. Our next study involving more embryo samples will investigate systematic changes in tissue mechanics during embryonic development.
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Affiliation(s)
- Jitao Zhang
- Fischell Department of Bioengineering, University of Maryland, Maryland
| | - Raksha Raghunathan
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Justin Rippy
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Chen Wu
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Richard H Finnell
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas
| | - Kirill V Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas.,Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas.,Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
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41
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Edrei E, Scarcelli G. Brillouin micro-spectroscopy through aberrations via sensorless adaptive optics. APPLIED PHYSICS LETTERS 2018; 112:163701. [PMID: 29713091 PMCID: PMC5902333 DOI: 10.1063/1.5027838] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 03/30/2018] [Indexed: 05/04/2023]
Abstract
Brillouin spectroscopy is a powerful optical technique for non-contact viscoelastic characterizations which has recently found applications in three-dimensional mapping of biological samples. Brillouin spectroscopy performances are rapidly degraded by optical aberrations and have therefore been limited to homogenous transparent samples. In this work, we developed an adaptive optics (AO) configuration designed for Brillouin scattering spectroscopy to engineer the incident wavefront and correct for aberrations. Our configuration does not require direct wavefront sensing and the injection of a "guide-star"; hence, it can be implemented without the need for sample pre-treatment. We used our AO-Brillouin spectrometer in aberrated phantoms and biological samples and obtained improved precision and resolution of Brillouin spectral analysis; we demonstrated 2.5-fold enhancement in Brillouin signal strength and 1.4-fold improvement in axial resolution because of the correction of optical aberrations.
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Affiliation(s)
- Eitan Edrei
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
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42
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Weber IP, Yun SH, Scarcelli G, Franze K. The role of cell body density in ruminant retina mechanics assessed by atomic force and Brillouin microscopy. Phys Biol 2017; 14:065006. [PMID: 28406094 DOI: 10.1088/1478-3975/aa6d18] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cells in the central nervous system (CNS) respond to the stiffness of their environment. CNS tissue is mechanically highly heterogeneous, thus providing motile cells with region-specific mechanical signals. While CNS mechanics has been measured with a variety of techniques, reported values of tissue stiffness vary greatly, and the morphological structures underlying spatial changes in tissue stiffness remain poorly understood. We here exploited two complementary techniques, contact-based atomic force microscopy and contact-free Brillouin microscopy, to determine the mechanical properties of ruminant retinae, which are built up by different tissue layers. As in all vertebrate retinae, layers of high cell body densities ('nuclear layers') alternate with layers of low cell body densities ('plexiform layers'). Different tissue layers varied significantly in their mechanical properties, with the photoreceptor layer being the stiffest region of the retina, and the inner plexiform layer belonging to the softest regions. As both techniques yielded similar results, our measurements allowed us to calibrate the Brillouin microscopy measurements and convert the Brillouin shift into a quantitative assessment of elastic tissue stiffness with optical resolution. Similar as in the mouse spinal cord and the developing Xenopus brain, we found a strong correlation between nuclear densities and tissue stiffness. Hence, the cellular composition of retinae appears to strongly contribute to local tissue stiffness, and Brillouin microscopy shows a great potential for the application in vivo to measure the mechanical properties of transparent tissues.
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Affiliation(s)
- Isabell P Weber
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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Raghunathan R, Zhang J, Wu C, Rippy J, Singh M, Larin KV, Scarcelli G. Evaluating biomechanical properties of murine embryos using Brillouin microscopy and optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-6. [PMID: 28861955 PMCID: PMC5582619 DOI: 10.1117/1.jbo.22.8.086013] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/03/2017] [Indexed: 05/19/2023]
Abstract
Embryogenesis is regulated by numerous changes in mechanical properties of the cellular microenvironment. Thus, studying embryonic mechanophysiology can provide a more thorough perspective of embryonic development, potentially improving early detection of congenital abnormalities as well as evaluating and developing therapeutic interventions. A number of methods and techniques have been used to study cellular biomechanical properties during embryogenesis. While some of these techniques are invasive or involve the use of external agents, others are compromised in terms of spatial and temporal resolutions. We propose the use of Brillouin microscopy in combination with optical coherence tomography (OCT) to measure stiffness as well as structural changes in a developing embryo. While Brillouin microscopy assesses the changes in stiffness among different organs of the embryo, OCT provides the necessary structural guidance.
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Affiliation(s)
- Raksha Raghunathan
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Jitao Zhang
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
| | - Chen Wu
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Justin Rippy
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Manmohan Singh
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Tomsk State University, Interdisciplinary Laboratory of Biophotonics, Tomsk, Russia
- Address all correspondence to: Kirill V. Larin, E-mail: ; Giuliano Scarcelli, E-mail:
| | - Giuliano Scarcelli
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
- Address all correspondence to: Kirill V. Larin, E-mail: ; Giuliano Scarcelli, E-mail:
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