title: Spectroscopic investigation of local mechanical impedance of living cells.
abstract: We studied nanoscale mechanical properties of PC12 living cells with a Force Feedback Microscope using two experimental approaches. The first one consists in measuring the local mechanical impedance of the cell membrane while simultaneously mapping the cell morphology at constant force. As the interaction force is increased, we observe the appearance of the sub-membrane cytoskeleton. We compare our findings with the outcome of other techniques. The second experimental approach consists in a spectroscopic investigation of the cell while varying the tip indentation into the membrane and consequently the applied force. At variance with conventional dynamic Atomic Force Microscopy techniques, here it is not mandatory to work at the first oscillation eigenmode of the cantilever: the excitation frequency of the tip can be chosen arbitrary leading then to new spectroscopic AFM techniques. We found in this way that the mechanical response of the PC12 cell membrane is found to be frequency dependent in the 1 kHz - 10 kHz range. In particular, we observe that the damping coefficient consistently decreases when the excitation frequency is increased.
authors.affiliation: European Synchrotron Radiation Facility, Grenoble, France; Université Joseph Fourier, Grenoble, France.
authors.forename: Luca
authors.initials: L
authors.lastname: Costa
authors.affiliation: Centro de Física da Matéria Condensada/Dep. Fisica, Faculdade de Ciência, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Mario S
authors.initials: MS
authors.lastname: Rodrigues
authors.affiliation: Astbury Centre for Structural Molecular Biology, Leeds University, Leeds, United Kingdom.
authors.forename: Núria
authors.initials: N
authors.lastname: Benseny-Cases
authors.affiliation: Astbury Centre for Structural Molecular Biology, Leeds University, Leeds, United Kingdom.
authors.forename: Véronique
authors.initials: V
authors.lastname: Mayeux
authors.affiliation: Centre National de la Recherche Scientifique, Institut NÉEL, Grenoble, France; Université Grenoble Alpes, Institut NÉEL, Grenoble, France.
authors.forename: Joël
authors.initials: J
authors.lastname: Chevrier
authors.affiliation: European Synchrotron Radiation Facility, Grenoble, France.
authors.forename: Fabio
authors.initials: F
authors.lastname: Comin
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D025461:Feedback, Physiological; D055595:Mechanical Phenomena; D018625:Microscopy, Atomic Force / Q000295:instrumentation / Q000379:methods*; D055100:Optical Fibers; D016716:PC12 Cells; D051381:Rats; D013057:Spectrum Analysis