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Gandin A, Murugesan Y, Torresan V, Ulliana L, Citron A, Contessotto P, Battilana G, Panciera T, Ventre M, Netti AP, Nicola L, Piccolo S, Brusatin G. Simple yet effective methods to probe hydrogel stiffness for mechanobiology. Sci Rep 2021; 11:22668. [PMID: 34811382 PMCID: PMC8608946 DOI: 10.1038/s41598-021-01036-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/13/2021] [Indexed: 01/20/2023] Open
Abstract
In spite of tremendous advances made in the comprehension of mechanotransduction, implementation of mechanobiology assays remains challenging for the broad community of cell biologists. Hydrogel substrates with tunable stiffness are essential tool in mechanobiology, allowing to investigate the effects of mechanical signals on cell behavior. A bottleneck that slows down the popularization of hydrogel formulations for mechanobiology is the assessment of their stiffness, typically requiring expensive and sophisticated methodologies in the domain of material science. Here we overcome such barriers offering the reader protocols to set-up and interpret two straightforward, low cost and high-throughput tools to measure hydrogel stiffness: static macroindentation and micropipette aspiration. We advanced on how to build up these tools and on the underlying theoretical modeling. Specifically, we validated our tools by comparing them with leading techniques used for measuring hydrogel stiffness (atomic force microscopy, uniaxial compression and rheometric analysis) with consistent results on PAA hydrogels or their modification. In so doing, we also took advantage of YAP/TAZ nuclear localization as biologically validated and sensitive readers of mechanosensing, all in all presenting a suite of biologically and theoretically proven protocols to be implemented in most biological laboratories to approach mechanobiology.
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Affiliation(s)
- Alessandro Gandin
- Department of Industrial Engineering, University of Padova and INSTM, via Marzolo 9, 35131, Padova, Italy
| | - Yaswanth Murugesan
- Department of Industrial Engineering, University of Padova, via Marzolo 9, 35131, Padova, Italy
| | - Veronica Torresan
- Department of Industrial Engineering, University of Padova and INSTM, via Marzolo 9, 35131, Padova, Italy
| | - Lorenzo Ulliana
- Department of Industrial Engineering, University of Padova and INSTM, via Marzolo 9, 35131, Padova, Italy
| | - Anna Citron
- Department of Molecular Medicine, University of Padova, via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Paolo Contessotto
- Department of Molecular Medicine, University of Padova, via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Giusy Battilana
- Department of Molecular Medicine, University of Padova, via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Tito Panciera
- Department of Molecular Medicine, University of Padova, via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Maurizio Ventre
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, 80125, Naples, Italy.,Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano Di Tecnologia, L.go Barsanti e Matteucci 53, 80125, Naples, Italy
| | - A Paolo Netti
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, 80125, Naples, Italy.,Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano Di Tecnologia, L.go Barsanti e Matteucci 53, 80125, Naples, Italy
| | - Lucia Nicola
- Department of Industrial Engineering, University of Padova, via Marzolo 9, 35131, Padova, Italy
| | - Stefano Piccolo
- Department of Molecular Medicine, University of Padova, via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Giovanna Brusatin
- Department of Industrial Engineering, University of Padova and INSTM, via Marzolo 9, 35131, Padova, Italy.
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Lee D, Rahman MM, Zhou Y, Ryu S. Three-Dimensional Confocal Microscopy Indentation Method for Hydrogel Elasticity Measurement. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9684-9693. [PMID: 26270154 DOI: 10.1021/acs.langmuir.5b01267] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The stiffness of the extracellular matrix (ECM) plays an important role in controlling cell functions. As an alternative to the ECM, hydrogels of tunable elasticity are widely used for in vitro cell mechanobiology studies. Therefore, characterizing the Young's modulus of the hydrogel substrate is crucial. In this paper, we propose a confocal microscopy indentation method for measuring the elasticity of polyacrylamide gel as a model hydrogel. Our new indentation method is based on three-dimensional imaging of the indented gel using confocal microscopy and automated image processing to measure indentation depth from the three-dimensional image stack. We tested and validated our method by indenting polyacrylamide gels of different rigidities with various sphere indentors and by comparing it with the rheometric method. Our measurements show consistent results regardless of the type of the indentors and agree with rheometric measurements. Therefore, the proposed confocal microscopy indentation method can accurately measure the stiffness of hydrogels.
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Affiliation(s)
- Donghee Lee
- Department of Mechanical & Materials Engineering and ‡Center for Biotechnology, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Md Mahmudur Rahman
- Department of Mechanical & Materials Engineering and ‡Center for Biotechnology, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - You Zhou
- Department of Mechanical & Materials Engineering and ‡Center for Biotechnology, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Sangjin Ryu
- Department of Mechanical & Materials Engineering and ‡Center for Biotechnology, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
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Eberwein P, Steinberg T, Schulz S, Zimmermann D, Accardi R, Beck D, Reinhard T, Tomakidi P. Expression of keratinocyte biomarkers is governed by environmental biomechanics. Eur J Cell Biol 2011; 90:1029-40. [DOI: 10.1016/j.ejcb.2011.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 08/01/2011] [Accepted: 08/01/2011] [Indexed: 10/16/2022] Open
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