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Issue 13, 2014
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Microrheology of cells with magnetic force modulation atomic force microscopy

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Abstract

We propose a magnetic force modulation method to measure the stiffness and viscosity of living cells using a modified AFM apparatus. An oscillating magnetic field makes a magnetic cantilever oscillate in contact with the sample, producing a small AC indentation. By comparing the amplitude of the free cantilever motion (A0) with the motion of the cantilever in contact with the sample (A1), we determine the sample stiffness and viscosity. To test the method, the frequency-dependent stiffness of 3T3 fibroblasts was determined as a power law ks(f) = α + β(f/[f with combining macron])γ (α = 7.6 × 10−4 N m−1, β = 1.0 × 10−4 N m−1, [f with combining macron] = 1 Hz, γ = 0.6), where the coefficient γ = 0.6 is in good agreement with rheological data of actin solutions with concentrations similar to those in cells. The method also allows estimation of the internal friction of the cells. In particular we found an average damping coefficient of 75.1 μN s m−1 for indentation depths ranging between 1.0 μm and 2.0 μm.

Graphical abstract: Microrheology of cells with magnetic force modulation atomic force microscopy

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Publication details

The article was received on 29 Jul 2013, accepted on 06 Dec 2013 and first published on 09 Dec 2013


Article type: Paper
DOI: 10.1039/C3SM52045E
Citation: Soft Matter, 2014,10, 2141-2149
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    Microrheology of cells with magnetic force modulation atomic force microscopy

    L. M. Rebêlo, J. S. de Sousa, J. M. Filho, J. Schäpe, H. Doschke and M. Radmacher, Soft Matter, 2014, 10, 2141
    DOI: 10.1039/C3SM52045E

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