Scientific Results

Scanning ion conductance microscopy (SICM): from measuring cell mechanical properties to guiding neuron growth

Year: 2013

Authors: Pellegrino M., Orsini P., Pellegrini M., 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, Piazza dei Cavalieri 7, 56126 Pisa, Italy; Istituto Nazionale di Ottica, Consiglio Nazionale Delle Ricerche, Via Moruzzi 1, 56124 Pisa, Italy

Abstract: Scanning ion conductance microscopy (SICM) is a type of scanning probe microscopy based on the continuous measurement of an ion current flowing through a pipette filled with an electrolyte solution, while the pipette apex approaches a non-conductive sample. This technique can be operated in environmental conditions such as those of cell cultures and does not require a direct contact between probe and sample. It is therefore particularly suitable for the investigation of living specimens. SICM was initially proposed as an instrument that could obtain topographic 3D images with high resolution. Later, simple modifications have been devised to apply a mechanical stimulus to the specimen via a solution flux coming out from the pipette aperture. This modified setup has been employed to measure cell membrane elasticity and to guide the growth cones of neurons for tens of micrometers, by means of repeated non-contact scanning. Both these applications require an accurate measurement of the mechanical forces acting on the cell surface, which can be obtained by combining SICM, Atomic force microscopy (AFM) and inverted optical microscopy in the same apparatus. In this configuration, a SICM pipette is approached to an AFM cantilever while monitoring the cantilever deflection as a function of the pressure applied to the pipette and the relative distance. In addition, the pipette aperture can be imaged in situ by exploiting the AFM operation, so that all the experimental parameters can be effectively controlled in the investigation of pressure effects on living cells.

Conference title: Optical Methods for Inspection, characterization and imaging of biomaterials (SPIE)
Place: Monaco, Germania

KeyWords: scanning ion conductance microscopy; atomic force microscopy; topographic image; cell mechanical properties; neuronal growth cone
DOI: 10.1117/12.2021541

English