Scientific Results

Measuring the elastic properties of living cells through the analysis of current-displacement curves in scanning ion conductance microscopy

Year: 2012

Authors: Pellegrino M., Pellegrini M., Orsini P., Tognoni E., Ascoli C., Baschieri P., Dinelli F.

Autors Affiliation: Dipartimento di Scienze Fisiologiche, Università di Pisa, Via S. Zeno 31, 56127 Pisa, Italy; Scuola Normale Superiore di Pisa, Piazza dei Cavalieri 7, 56126 Pisa, Italy; Istituto Nazionale di Ottica del CNR, Via moruzzi 1, 56124 Pisa, Italy

Abstract: Knowledge of mechanical properties of living cells is essential to understand their physiological and pathological conditions. To measure local cellular elasticity, scanning probe techniques have been increasingly employed. In particular, non-contact scanning ion conductance microscopy (SICM) has been used for this purpose; thanks to the application of a hydrostatic pressure via the SICM pipette. However, the measurement of sample deformations induced by weak pressures at a short distance has not yet been carried out. A direct quantification of the applied pressure has not been also achieved up to now. These two issues are highly relevant, especially when one addresses the investigation of thin cell regions. In this paper, we present an approach to solve these problems based on the use of a setup integrating SICM, atomic force microscopy, and optical microscopy. In particular, we describe how we can directly image the pipette aperture in situ. Additionally, we can measure the force induced by a constant hydrostatic pressure applied via the pipette over the entire probe-sample distance range from a remote point to contact. Then, we demonstrate that the sample deformation induced by an external pressure applied to the pipette can be indirectly and reliably evaluated from the analysis of the current-displacement curves. This method allows us to measure the linear relationship between indentation and applied pressure on uniformly deformable elastomers of known Young\’s modulus. Finally, we apply the method to murine fibroblasts and we show that it is sensitive to local and temporally induced variations of the cell surface elasticity.

Journal/Review: PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY

Volume: 464 (3)      Pages from: 307  to: 316

More Information: The authors wish to thank Francesco Montanari for his expert technical assistance. This work has been partially supported by funds of the Scuola Normale Superiore of Pisa.
KeyWords: Atomic force microscopy; Cell elasticity; Scanning ion conductance microscopy
DOI: 10.1007/s00424-012-1127-6

Citations: 16
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English