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Title: Passive microrheology of normal and cancer cells after ML7 treatment by atomic force microscopy

Abstract

Mechanical properties of living cancer and normal thyroidal cells were investigated by atomic force microscopy (AFM). Cell mechanics was compared before and after treatment with ML7, which is known to reduce myosin activity and induce softening of cell structures. We recorded force curves with extended dwell time of 6 seconds in contact at maximum forces from 500 pN to 1 nN. Data were analyzed within different frameworks: Hertz fit was applied in order to evaluate differences in Young’s moduli among cell types and conditions, while the fluctuations of the cantilever in contact with cells were analyzed with both conventional algorithms (probability density function and power spectral density) and multifractal detrended fluctuation analysis (MF-DFA). We found that cancer cells were softer than normal cells and ML7 had a substantial softening effect on normal cells, but only a marginal one on cancer cells. Moreover, we observed that all recorded signals for normal and cancer cells were monofractal with small differences between their scaling parameters. Finally, the applicability of wavelet-based methods of data analysis for the discrimination of different cell types is discussed.

Authors:
 [1];  [2]; ; ;  [1]; ;  [3]
  1. Institute of Continuous Media Mechanics, Ak. Korolev Str. 1, Perm, 614013 (Russian Federation)
  2. (Russian Federation)
  3. Institute of Biophysics, University of Bremen, Otto-Hahn-Allee 1, NW1, Bremen, 28359 Germany (Germany)
Publication Date:
OSTI Identifier:
22608283
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1760; Journal Issue: 1; Conference: PC'16: International conference on physics of cancer: Interdisciplinary problems and clinical applications 2016, Tomsk (Russian Federation), 22-25 Mar 2016; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ALGORITHMS; ATOMIC FORCE MICROSCOPY; COMPARATIVE EVALUATIONS; DATA ANALYSIS; DEFEROXAMINE; DENSITY; FLUCTUATIONS; MYOSIN; NEOPLASMS; PROBABILITY; PROBABILITY DENSITY FUNCTIONS; SPECTRAL DENSITY

Citation Formats

Lyapunova, Elena, E-mail: lyapunova@icmm.ru, Ural Federal University, Kuibyishev Str. 48, Ekaterinburg, 620000, Nikituk, Alexander, E-mail: nas@icmm.ru, Bayandin, Yuriy, Naimark, Oleg, E-mail: naimark@icmm.ru, Rianna, Carmela, E-mail: cr@biophysik.uni-bremen.de, and Radmacher, Manfred, E-mail: mr@biophysik.uni-bremen.de. Passive microrheology of normal and cancer cells after ML7 treatment by atomic force microscopy. United States: N. p., 2016. Web. doi:10.1063/1.4960265.
Lyapunova, Elena, E-mail: lyapunova@icmm.ru, Ural Federal University, Kuibyishev Str. 48, Ekaterinburg, 620000, Nikituk, Alexander, E-mail: nas@icmm.ru, Bayandin, Yuriy, Naimark, Oleg, E-mail: naimark@icmm.ru, Rianna, Carmela, E-mail: cr@biophysik.uni-bremen.de, & Radmacher, Manfred, E-mail: mr@biophysik.uni-bremen.de. Passive microrheology of normal and cancer cells after ML7 treatment by atomic force microscopy. United States. doi:10.1063/1.4960265.
Lyapunova, Elena, E-mail: lyapunova@icmm.ru, Ural Federal University, Kuibyishev Str. 48, Ekaterinburg, 620000, Nikituk, Alexander, E-mail: nas@icmm.ru, Bayandin, Yuriy, Naimark, Oleg, E-mail: naimark@icmm.ru, Rianna, Carmela, E-mail: cr@biophysik.uni-bremen.de, and Radmacher, Manfred, E-mail: mr@biophysik.uni-bremen.de. 2016. "Passive microrheology of normal and cancer cells after ML7 treatment by atomic force microscopy". United States. doi:10.1063/1.4960265.
@article{osti_22608283,
title = {Passive microrheology of normal and cancer cells after ML7 treatment by atomic force microscopy},
author = {Lyapunova, Elena, E-mail: lyapunova@icmm.ru and Ural Federal University, Kuibyishev Str. 48, Ekaterinburg, 620000 and Nikituk, Alexander, E-mail: nas@icmm.ru and Bayandin, Yuriy and Naimark, Oleg, E-mail: naimark@icmm.ru and Rianna, Carmela, E-mail: cr@biophysik.uni-bremen.de and Radmacher, Manfred, E-mail: mr@biophysik.uni-bremen.de},
abstractNote = {Mechanical properties of living cancer and normal thyroidal cells were investigated by atomic force microscopy (AFM). Cell mechanics was compared before and after treatment with ML7, which is known to reduce myosin activity and induce softening of cell structures. We recorded force curves with extended dwell time of 6 seconds in contact at maximum forces from 500 pN to 1 nN. Data were analyzed within different frameworks: Hertz fit was applied in order to evaluate differences in Young’s moduli among cell types and conditions, while the fluctuations of the cantilever in contact with cells were analyzed with both conventional algorithms (probability density function and power spectral density) and multifractal detrended fluctuation analysis (MF-DFA). We found that cancer cells were softer than normal cells and ML7 had a substantial softening effect on normal cells, but only a marginal one on cancer cells. Moreover, we observed that all recorded signals for normal and cancer cells were monofractal with small differences between their scaling parameters. Finally, the applicability of wavelet-based methods of data analysis for the discrimination of different cell types is discussed.},
doi = {10.1063/1.4960265},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1760,
place = {United States},
year = 2016,
month = 8
}
  • Compared to active microrheology where a known force or modulation is periodically imposed to a soft material, passive microrheology relies on the spectral analysis of the spontaneous motion of tracers inherent or external to the material. Passive microrheology studies of soft or living materials with atomic force microscopy (AFM) cantilever tips are rather rare because, in the spectral densities, the rheological response of the materials is hardly distinguishable from other sources of random or periodic perturbations. To circumvent this difficulty, we propose here a wavelet-based decomposition of AFM cantilever tip fluctuations and we show that when applying this multi-scale methodmore » to soft polymer layers and to living myoblasts, the structural damping exponents of these soft materials can be retrieved.« less
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  • To date, nanoscale imaging of the morphological changes and adhesion force of CD4{sup +} T cells during in vitro activation remains largely unreported. In this study, we used atomic force microscopy (AFM) to study the morphological changes and specific binding forces in resting and activated human peripheral blood CD4{sup +} T cells. The AFM images revealed that the volume of activated CD4{sup +} T cells increased and the ultrastructure of these cells also became complex. Using a functionalized AFM tip, the strength of the specific binding force of the CD4 antigen-antibody interaction was found to be approximately three times thatmore » of the unspecific force. The adhesion forces were not randomly distributed over the surface of a single activated CD4{sup +} T cell, indicated that the CD4 molecules concentrated into nanodomains. The magnitude of the adhesion force of the CD4 antigen-antibody interaction did not change markedly with the activation time. Multiple bonds involved in the CD4 antigen-antibody interaction were measured at different activation times. These results suggest that the adhesion force involved in the CD4 antigen-antibody interaction is highly selective and of high affinity.« less
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  • No abstract prepared.