Abstract

Micromechanical properties of biological cells are crucial for cells functions. Despite extensive study by a variety of approaches, an understanding of the subject remains elusive. We conducted a comparative study of the micromechanical properties of cultured alveolar epithelial cells with an oscillatory optical tweezer-based cytorheometer. In this study, the frequency-dependent viscoelasticity of these cells was measured by optical trapping and forced oscillation of either a submicron endogenous intracellular organelle (intra-cellular) or a 1.5µm silica bead attached to the cytoskeleton through trans-membrane integrin receptors (extra-cellular). Both the storage modulus and the magnitude of the complex shear modulus followed weak power-law dependence with frequency. These data are comparable to data obtained by other measurement techniques. The exponents of power-law dependence of the data from the intra- and extra-cellular measurements are similar; however, the differences in the magnitudes of the moduli from the two measurements are statistically significant.

© 2008 Optical Society of America

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  1. M. A. GimbroneJr., T. Nagel, and J. N. Topper, "Biomechanical activation: an emerging paradigm in endothelial adhesion biology," J. Clin. Invest. 99, 1809 (1997).
    [CrossRef]
  2. G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
    [PubMed]
  3. D. E. Ingber, "Tensegrity: the architectural basis of cellular mechanotransduction," Annu. Rev. Physiol. 59, 575 (1997).
    [CrossRef] [PubMed]
  4. M. Liu, A. K. Tanswell, and M. Post, "Mechanical force-induced signal transduction in lung cells," Am. J. Physiol. 277, L667 (1999).
    [PubMed]
  5. H. R. Wirtz and L. G. Dobbs, "The effects of mechanical forces on lung functions," Respir. Physiol. 119, 1 (2000).
    [CrossRef] [PubMed]
  6. H. L. Dailey, H. C. Yalcin, and S. N. Ghadiali, "Fluid-structure modeling of flow-induced alveolar epithelial cell deformation," Comput. Struct. 85, 1066 (2007).
    [CrossRef]
  7. H. C. Yalcin, S. F. Perry, and S. N. Ghadiali, "Influence of airway diameter and cell confluence on epithelial cell injury in an in vitro model of airway reopening," J. Appl. Physiol. 103,1796-1807 (2007).
    [CrossRef] [PubMed]
  8. B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
    [CrossRef] [PubMed]
  9. B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
    [CrossRef] [PubMed]
  10. S. Yamada, D. Wirtz, and S. C. Kuo, "Mechanics of Living Cells Measured by Laser Tracking Microrheology," Biophys. J. 78, 1736 (2000).
    [CrossRef] [PubMed]
  11. M. Mengistu, L. Lowe-Krentz, and H. D. Ou-Yang, "Physical Properties of the Transcytosis Machinery in Endothelial Cells," Am. Soc. Cell Biology Annual Meeting (2006).
  12. L. A. Hough, "Microrheology of Soft Materials Using Oscillating Optical Traps," Ph.D. thesis, Lehigh University (2003).
  13. L. A. Hough and H. D. Ou-Yang, "Viscoelasticity of aqueous telechelic poly(ethylene oxide) solutions: Relaxation and structure," Phys. Rev. E. 73 (2006).
    [CrossRef]
  14. M. T. Valentine, L. E. Dewalt, and H. D. Ou-Yang, "Forces on a colloidal particle in a polymer solution: a study using optical tweezers," J. Phys. Condens. Matter 8, 9477 (1996).
    [CrossRef]
  15. A. M. Bilek, K. C. Dee, and D. P. Gaver, 3rd, "Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 94, 770 (2003).
  16. S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
    [CrossRef] [PubMed]
  17. K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
    [CrossRef]
  18. D. J. Tschumperlin and S. S. Margulies, "Equibiaxial deformation-induced injury of alveolar epithelial cells in vitro," Am. J. Physiol. 275, L1173 (1998).
    [PubMed]
  19. D. Choquet, D. P. Felsenfeld, and M. P. Sheetz, "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages," Cell 88, 39 (1997).
    [CrossRef] [PubMed]
  20. L. A. Hough and H. D. Ou-Yang, "Correlated motions of two hydrodynamically coupled particles confined in separate quadratic potential wells," Phys. Rev. E. 65, 021906 (2002).
    [CrossRef]
  21. M. T. Wei and A. Chiou, "Three-dimensional tracking of Brownian motion of a particle trapped in optical tweezers with a pair of orthogonal tracking beams and the determination of the associated optical force constants," Opt. Express 13, 5798 (2005).
    [CrossRef] [PubMed]
  22. M. T. Wei, K. Yang, A. Karmenyan, and A. Chiou, "Three-dimensional optical force field on a Chinese hamster ovary cell in a fiber-optical dual-beam trap," Opt. Express 14, 3056 (2006).
    [CrossRef] [PubMed]
  23. E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
    [CrossRef]
  24. V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
    [CrossRef] [PubMed]
  25. K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
    [CrossRef] [PubMed]
  26. A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm, and S. Chu, "Observation of a single-beam gradient force optical trap for dielectric particles," Opt. Lett. 11, 288-290 (1986).
    [CrossRef] [PubMed]
  27. H. D. Ou-Yang, Polymer-Colloid Interactions: From Fundamentals to Practice (John Wiley and Sons, New York, 1999), Chap. 15.
  28. A. Rohrbach, "Stiffness of optical traps: quantitative agreement between experiment and electromagnetic theory," Phys. Rev. Lett. 95, 168102 (2005).
    [CrossRef] [PubMed]
  29. M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
    [CrossRef]
  30. X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
    [CrossRef] [PubMed]

2007

H. L. Dailey, H. C. Yalcin, and S. N. Ghadiali, "Fluid-structure modeling of flow-induced alveolar epithelial cell deformation," Comput. Struct. 85, 1066 (2007).
[CrossRef]

H. C. Yalcin, S. F. Perry, and S. N. Ghadiali, "Influence of airway diameter and cell confluence on epithelial cell injury in an in vitro model of airway reopening," J. Appl. Physiol. 103,1796-1807 (2007).
[CrossRef] [PubMed]

2006

B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
[CrossRef] [PubMed]

L. A. Hough and H. D. Ou-Yang, "Viscoelasticity of aqueous telechelic poly(ethylene oxide) solutions: Relaxation and structure," Phys. Rev. E. 73 (2006).
[CrossRef]

M. T. Wei, K. Yang, A. Karmenyan, and A. Chiou, "Three-dimensional optical force field on a Chinese hamster ovary cell in a fiber-optical dual-beam trap," Opt. Express 14, 3056 (2006).
[CrossRef] [PubMed]

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

2005

M. T. Wei and A. Chiou, "Three-dimensional tracking of Brownian motion of a particle trapped in optical tweezers with a pair of orthogonal tracking beams and the determination of the associated optical force constants," Opt. Express 13, 5798 (2005).
[CrossRef] [PubMed]

A. Rohrbach, "Stiffness of optical traps: quantitative agreement between experiment and electromagnetic theory," Phys. Rev. Lett. 95, 168102 (2005).
[CrossRef] [PubMed]

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

2004

S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
[CrossRef] [PubMed]

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

2003

A. M. Bilek, K. C. Dee, and D. P. Gaver, 3rd, "Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 94, 770 (2003).

2002

L. A. Hough and H. D. Ou-Yang, "Correlated motions of two hydrodynamically coupled particles confined in separate quadratic potential wells," Phys. Rev. E. 65, 021906 (2002).
[CrossRef]

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

2001

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

2000

S. Yamada, D. Wirtz, and S. C. Kuo, "Mechanics of Living Cells Measured by Laser Tracking Microrheology," Biophys. J. 78, 1736 (2000).
[CrossRef] [PubMed]

H. R. Wirtz and L. G. Dobbs, "The effects of mechanical forces on lung functions," Respir. Physiol. 119, 1 (2000).
[CrossRef] [PubMed]

1999

M. Liu, A. K. Tanswell, and M. Post, "Mechanical force-induced signal transduction in lung cells," Am. J. Physiol. 277, L667 (1999).
[PubMed]

1998

D. J. Tschumperlin and S. S. Margulies, "Equibiaxial deformation-induced injury of alveolar epithelial cells in vitro," Am. J. Physiol. 275, L1173 (1998).
[PubMed]

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
[CrossRef]

1997

D. Choquet, D. P. Felsenfeld, and M. P. Sheetz, "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages," Cell 88, 39 (1997).
[CrossRef] [PubMed]

D. E. Ingber, "Tensegrity: the architectural basis of cellular mechanotransduction," Annu. Rev. Physiol. 59, 575 (1997).
[CrossRef] [PubMed]

M. A. GimbroneJr., T. Nagel, and J. N. Topper, "Biomechanical activation: an emerging paradigm in endothelial adhesion biology," J. Clin. Invest. 99, 1809 (1997).
[CrossRef]

1996

M. T. Valentine, L. E. Dewalt, and H. D. Ou-Yang, "Forces on a colloidal particle in a polymer solution: a study using optical tweezers," J. Phys. Condens. Matter 8, 9477 (1996).
[CrossRef]

1992

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

1986

Ashkin, A.

Asnacios, A.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Audus, K. L.

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

Avery, M. L.

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

Balland, M.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Bilek, A. M.

S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
[CrossRef] [PubMed]

A. M. Bilek, K. C. Dee, and D. P. Gaver, 3rd, "Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 94, 770 (2003).

Bjorkholm, J. E.

Browaeys, J.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Butler, J. P.

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

Chiou, A.

Choquet, D.

D. Choquet, D. P. Felsenfeld, and M. P. Sheetz, "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages," Cell 88, 39 (1997).
[CrossRef] [PubMed]

Chou, Y.-H.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Chu, S.

Crocker, J. C.

B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
[CrossRef] [PubMed]

Dailey, H. L.

H. L. Dailey, H. C. Yalcin, and S. N. Ghadiali, "Fluid-structure modeling of flow-induced alveolar epithelial cell deformation," Comput. Struct. 85, 1066 (2007).
[CrossRef]

Dee, K. C.

S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
[CrossRef] [PubMed]

A. M. Bilek, K. C. Dee, and D. P. Gaver, 3rd, "Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 94, 770 (2003).

Desprat, N.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Dewalt, L. E.

M. T. Valentine, L. E. Dewalt, and H. D. Ou-Yang, "Forces on a colloidal particle in a polymer solution: a study using optical tweezers," J. Phys. Condens. Matter 8, 9477 (1996).
[CrossRef]

Dobbs, L. G.

H. R. Wirtz and L. G. Dobbs, "The effects of mechanical forces on lung functions," Respir. Physiol. 119, 1 (2000).
[CrossRef] [PubMed]

Dziedzic, J. M.

Fabry, B.

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

Farre, R.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

Felsenfeld, D. P.

D. Choquet, D. P. Felsenfeld, and M. P. Sheetz, "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages," Cell 88, 39 (1997).
[CrossRef] [PubMed]

Féréol, S.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Flitney, F. W.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Florin, E. L.

E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
[CrossRef]

Fodil, R.

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Foster, K. A.

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

Fredberg, J. J.

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

Gallet, F.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Gaver, D. P.

S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
[CrossRef] [PubMed]

A. M. Bilek, K. C. Dee, and D. P. Gaver, 3rd, "Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 94, 770 (2003).

Gerlach, G. F.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

Ghadiali, S. N.

H. L. Dailey, H. C. Yalcin, and S. N. Ghadiali, "Fluid-structure modeling of flow-induced alveolar epithelial cell deformation," Comput. Struct. 85, 1066 (2007).
[CrossRef]

H. C. Yalcin, S. F. Perry, and S. N. Ghadiali, "Influence of airway diameter and cell confluence on epithelial cell injury in an in vitro model of airway reopening," J. Appl. Physiol. 103,1796-1807 (2007).
[CrossRef] [PubMed]

Gimbrone, M. A.

M. A. GimbroneJr., T. Nagel, and J. N. Topper, "Biomechanical activation: an emerging paradigm in endothelial adhesion biology," J. Clin. Invest. 99, 1809 (1997).
[CrossRef]

Glogauer, M.

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

Goldman, R. D.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Goldspink, G.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

Grabulosa, M.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

Henon, S.

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Hénon, S.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Hoffman, B. D.

B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
[CrossRef] [PubMed]

Horber, J. K. H.

E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
[CrossRef]

Hough, L. A.

L. A. Hough and H. D. Ou-Yang, "Viscoelasticity of aqueous telechelic poly(ethylene oxide) solutions: Relaxation and structure," Phys. Rev. E. 73 (2006).
[CrossRef]

L. A. Hough and H. D. Ou-Yang, "Correlated motions of two hydrodynamically coupled particles confined in separate quadratic potential wells," Phys. Rev. E. 65, 021906 (2002).
[CrossRef]

Icard, D.

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Ingber, D. E.

D. E. Ingber, "Tensegrity: the architectural basis of cellular mechanotransduction," Annu. Rev. Physiol. 59, 575 (1997).
[CrossRef] [PubMed]

Isabey, D.

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Jaenicke, T.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

Karmenyan, A.

Kay, S. S.

S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
[CrossRef] [PubMed]

Kuczmarski, E. R.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Kuo, S. C.

S. Yamada, D. Wirtz, and S. C. Kuo, "Mechanics of Living Cells Measured by Laser Tracking Microrheology," Biophys. J. 78, 1736 (2000).
[CrossRef] [PubMed]

Laurent, V. M.

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Linz, L.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Liu, M.

M. Liu, A. K. Tanswell, and M. Post, "Mechanical force-induced signal transduction in lung cells," Am. J. Physiol. 277, L667 (1999).
[PubMed]

Loughna, P. T.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

Maksym, G. N.

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

Maksym, G.N.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

Margulies, S. S.

D. J. Tschumperlin and S. S. Margulies, "Equibiaxial deformation-induced injury of alveolar epithelial cells in vitro," Am. J. Physiol. 275, L1173 (1998).
[PubMed]

Massiera, G.

B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
[CrossRef] [PubMed]

Mayer, M. M.

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

Nagel, T.

M. A. GimbroneJr., T. Nagel, and J. N. Topper, "Biomechanical activation: an emerging paradigm in endothelial adhesion biology," J. Clin. Invest. 99, 1809 (1997).
[CrossRef]

Navajas, D.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

Omary, M. B.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Oster, C.G.

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

Ou-Yang, H. D.

L. A. Hough and H. D. Ou-Yang, "Viscoelasticity of aqueous telechelic poly(ethylene oxide) solutions: Relaxation and structure," Phys. Rev. E. 73 (2006).
[CrossRef]

L. A. Hough and H. D. Ou-Yang, "Correlated motions of two hydrodynamically coupled particles confined in separate quadratic potential wells," Phys. Rev. E. 65, 021906 (2002).
[CrossRef]

M. T. Valentine, L. E. Dewalt, and H. D. Ou-Yang, "Forces on a colloidal particle in a polymer solution: a study using optical tweezers," J. Phys. Condens. Matter 8, 9477 (1996).
[CrossRef]

Perry, S. F.

H. C. Yalcin, S. F. Perry, and S. N. Ghadiali, "Influence of airway diameter and cell confluence on epithelial cell injury in an in vitro model of airway reopening," J. Appl. Physiol. 103,1796-1807 (2007).
[CrossRef] [PubMed]

Planus, E.

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

Post, M.

M. Liu, A. K. Tanswell, and M. Post, "Mechanical force-induced signal transduction in lung cells," Am. J. Physiol. 277, L667 (1999).
[PubMed]

Pralle, A.

E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
[CrossRef]

Puig, F.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

Ridge, K. M.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Rohrbach, A.

A. Rohrbach, "Stiffness of optical traps: quantitative agreement between experiment and electromagnetic theory," Phys. Rev. Lett. 95, 168102 (2005).
[CrossRef] [PubMed]

Scutt, A.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

Sheetz, M. P.

D. Choquet, D. P. Felsenfeld, and M. P. Sheetz, "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages," Cell 88, 39 (1997).
[CrossRef] [PubMed]

Stelzer, E. H. K.

E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
[CrossRef]

Sznajder, J. I.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

Tanswell, A. K.

M. Liu, A. K. Tanswell, and M. Post, "Mechanical force-induced signal transduction in lung cells," Am. J. Physiol. 277, L667 (1999).
[PubMed]

Topper, J. N.

M. A. GimbroneJr., T. Nagel, and J. N. Topper, "Biomechanical activation: an emerging paradigm in endothelial adhesion biology," J. Clin. Invest. 99, 1809 (1997).
[CrossRef]

Trepat, X.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

Tschumperlin, D. J.

D. J. Tschumperlin and S. S. Margulies, "Equibiaxial deformation-induced injury of alveolar epithelial cells in vitro," Am. J. Physiol. 275, L1173 (1998).
[PubMed]

Valentine, M. T.

M. T. Valentine, L. E. Dewalt, and H. D. Ou-Yang, "Forces on a colloidal particle in a polymer solution: a study using optical tweezers," J. Phys. Condens. Matter 8, 9477 (1996).
[CrossRef]

Van Citters, K. M.

B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
[CrossRef] [PubMed]

Wei, M. T.

Wells, D. J.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

Wirtz, D.

S. Yamada, D. Wirtz, and S. C. Kuo, "Mechanics of Living Cells Measured by Laser Tracking Microrheology," Biophys. J. 78, 1736 (2000).
[CrossRef] [PubMed]

Wirtz, H. R.

H. R. Wirtz and L. G. Dobbs, "The effects of mechanical forces on lung functions," Respir. Physiol. 119, 1 (2000).
[CrossRef] [PubMed]

Yalcin, H. C.

H. C. Yalcin, S. F. Perry, and S. N. Ghadiali, "Influence of airway diameter and cell confluence on epithelial cell injury in an in vitro model of airway reopening," J. Appl. Physiol. 103,1796-1807 (2007).
[CrossRef] [PubMed]

H. L. Dailey, H. C. Yalcin, and S. N. Ghadiali, "Fluid-structure modeling of flow-induced alveolar epithelial cell deformation," Comput. Struct. 85, 1066 (2007).
[CrossRef]

Yamada, S.

S. Yamada, D. Wirtz, and S. C. Kuo, "Mechanics of Living Cells Measured by Laser Tracking Microrheology," Biophys. J. 78, 1736 (2000).
[CrossRef] [PubMed]

Yang, K.

Am. J. Physiol.

G. Goldspink, A. Scutt, P. T. Loughna, D. J. Wells, T. Jaenicke, and G. F. Gerlach, "Gene expression in skeletal muscle in response to stretch and force generation," Am. J. Physiol. 262, R356 (1992).
[PubMed]

M. Liu, A. K. Tanswell, and M. Post, "Mechanical force-induced signal transduction in lung cells," Am. J. Physiol. 277, L667 (1999).
[PubMed]

D. J. Tschumperlin and S. S. Margulies, "Equibiaxial deformation-induced injury of alveolar epithelial cells in vitro," Am. J. Physiol. 275, L1173 (1998).
[PubMed]

Am. J. Physiol. Lung Cell Mol. Physiol.

X. Trepat, M. Grabulosa, F. Puig, G.N. Maksym, D. Navajas, and R. Farre, "Viscoelasticity of human alveolar epithelial cells subjected to stretch," Am. J. Physiol. Lung Cell Mol. Physiol. (2004) July9.
[CrossRef] [PubMed]

Annu. Rev. Physiol.

D. E. Ingber, "Tensegrity: the architectural basis of cellular mechanotransduction," Annu. Rev. Physiol. 59, 575 (1997).
[CrossRef] [PubMed]

Biophys. J.

S. Yamada, D. Wirtz, and S. C. Kuo, "Mechanics of Living Cells Measured by Laser Tracking Microrheology," Biophys. J. 78, 1736 (2000).
[CrossRef] [PubMed]

Cell

D. Choquet, D. P. Felsenfeld, and M. P. Sheetz, "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages," Cell 88, 39 (1997).
[CrossRef] [PubMed]

Comput. Struct.

H. L. Dailey, H. C. Yalcin, and S. N. Ghadiali, "Fluid-structure modeling of flow-induced alveolar epithelial cell deformation," Comput. Struct. 85, 1066 (2007).
[CrossRef]

Exp. Cell Res.

K. A. Foster, C.G. Oster, M. M. Mayer, M. L. Avery, and K. L. Audus, "Characterization of the A549 cell line as a type II pulmonary epithelial cell model for drug metabolism," Exp. Cell Res. 243, 359 (1998).
[CrossRef] [PubMed]

J. Appl. Physiol.

H. C. Yalcin, S. F. Perry, and S. N. Ghadiali, "Influence of airway diameter and cell confluence on epithelial cell injury in an in vitro model of airway reopening," J. Appl. Physiol. 103,1796-1807 (2007).
[CrossRef] [PubMed]

A. M. Bilek, K. C. Dee, and D. P. Gaver, 3rd, "Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 94, 770 (2003).

S. S. Kay, A. M. Bilek, K. C. Dee, and D. P. GaverIII, "Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening," J. Appl. Physiol. 97, 269 (2004).
[CrossRef] [PubMed]

J. Bio. Chem.

K. M. Ridge, L. Linz, F. W. Flitney, E. R. Kuczmarski, Y.-H. Chou, M. B. Omary, J. I. Sznajder, and R. D. Goldman, "Keratin 8 Phosphorylation by Protein Kinase C {delta} Regulates Shear Stress-mediated Disassembly of Keratin Intermediate Filaments in Alveolar Epithelial Cells," J. Bio. Chem. 280, 30400 (2005).
[CrossRef]

J. Biomech. Eng.

V. M. Laurent, S. Henon, E. Planus, R. Fodil, M. Balland, D. Isabey, and F. Gallet "Assessment of mechanical properties of adherent living cells by bead micromanipulation: comparison of magnetic twisting cytometry vs. optical tweezers," J. Biomech. Eng. 124, 408 (2002).
[CrossRef] [PubMed]

J. Clin. Invest.

M. A. GimbroneJr., T. Nagel, and J. N. Topper, "Biomechanical activation: an emerging paradigm in endothelial adhesion biology," J. Clin. Invest. 99, 1809 (1997).
[CrossRef]

J. Phys. Condens. Matter

M. T. Valentine, L. E. Dewalt, and H. D. Ou-Yang, "Forces on a colloidal particle in a polymer solution: a study using optical tweezers," J. Phys. Condens. Matter 8, 9477 (1996).
[CrossRef]

Opt. Express

Opt. Lett.

Phys. A-Mater.

E. L. Florin, A. Pralle, E. H. K. Stelzer, and J. K. H. Horber, "Photonic force microscope calibration by thermal noise analysis," Appl.Phys. A-Mater. 66, S75 (1998).
[CrossRef]

Phys. Rev. E

M. Balland, N. Desprat, D. Icard, S. Féréol, A. Asnacios, J. Browaeys, S. Hénon, and F. Gallet, "Power laws in microrheology experiments on living cells: Comparative analysis and modeling," Phys. Rev. E 74, 021911 (2006)
[CrossRef]

Phys. Rev. E.

L. A. Hough and H. D. Ou-Yang, "Viscoelasticity of aqueous telechelic poly(ethylene oxide) solutions: Relaxation and structure," Phys. Rev. E. 73 (2006).
[CrossRef]

L. A. Hough and H. D. Ou-Yang, "Correlated motions of two hydrodynamically coupled particles confined in separate quadratic potential wells," Phys. Rev. E. 65, 021906 (2002).
[CrossRef]

Phys. Rev. Lett.

B. Fabry, G. N. Maksym, J. P. Butler, M. Glogauer, D. Navajas, and J. J. Fredberg, "Scaling the microrheology of living cells," Phys. Rev. Lett. 87,148102 (2001).
[CrossRef] [PubMed]

A. Rohrbach, "Stiffness of optical traps: quantitative agreement between experiment and electromagnetic theory," Phys. Rev. Lett. 95, 168102 (2005).
[CrossRef] [PubMed]

Proc. Natl. Acad. Sci. USA

B. D. Hoffman, G. Massiera, K. M. Van Citters, and J. C. Crocker, "The consensus mechanics of cultured mammalian cells," Proc. Natl. Acad. Sci. USA 103, 10259 (2006).
[CrossRef] [PubMed]

Respir. Physiol.

H. R. Wirtz and L. G. Dobbs, "The effects of mechanical forces on lung functions," Respir. Physiol. 119, 1 (2000).
[CrossRef] [PubMed]

Other

M. Mengistu, L. Lowe-Krentz, and H. D. Ou-Yang, "Physical Properties of the Transcytosis Machinery in Endothelial Cells," Am. Soc. Cell Biology Annual Meeting (2006).

L. A. Hough, "Microrheology of Soft Materials Using Oscillating Optical Traps," Ph.D. thesis, Lehigh University (2003).

H. D. Ou-Yang, Polymer-Colloid Interactions: From Fundamentals to Practice (John Wiley and Sons, New York, 1999), Chap. 15.

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Figures (8)

Fig. 1.
Fig. 1.

A schematic diagram of the integrin anti-body coated beads attaching to the plasma membrane (bead size not to scale).

Fig. 2.
Fig. 2.

A schematic diagram of the experimental setup. The area enclosed by the dashed lines represents an inverted optical microscope.

Fig. 3.
Fig. 3.

(a) The normalized amplitude (left), and (b) the relative phase (right) vs. the oscillation frequency of a 1.5 µm diameter silica bead in an oscillatory optical tweezers. The solid dots represent the experimental data and the solid lines are the fits with the spring constant kOT as the only fitting parameter.

Fig. 4.
Fig. 4.

(A) A sketch of optical tweezer-based cytorheometer. Optical tweezers were used to manipulate an intracellular granular structure (lamellar body, left circle), or an extracellular anti-body coated glass bead (right circle). (B) A bright-field image of lamellar bodies that abundantly exist in alveolar epithelial type II cells.

Fig. 5.
Fig. 5.

Experimental data obtained by using intracellular organelles as probes: (A) G′(ω) and G″(ω), (B) G*(ω). Solid lines represent power-law fits to G′ and G*

Fig. 6.
Fig. 6.

(A) G′(ω) and G″(ω), (B) G*(ω) probed with anti-integrin conjugated silica beads attached to the plasma membrane. Solid lines represent power-law fit to G′ and G*.

Fig. 7.
Fig. 7.

(A) Power-law exponents of G′ and G* for extracellular and intracellular data. Error bars represent standard deviation and means are not statistically different. (B) Magnitudes of prefactor G′o and G*o for extracellular and intracellular data. Error bars are 95% confidence intervals on log-scale and means are statistically different (p<0.01, log-transformed t-test).

Fig. 8.
Fig. 8.

(A) A bright-field image of cells with a membrane-bound bead. (B) A fluorescent image of actin cytoskeleton (phalloidin) with bead location outlined in blue. Images indicate minimal local restructuring of the actin cytoskeleton near the bead due to short duration of incubation (20 min).

Equations (7)

Equations on this page are rendered with MathJax. Learn more.

m x ̈ + 6 π η a x ̇ + k x = k OT [ A cos ( ω t ) x ]
D ( ω ) = A k O T ( k OT + k ) 2 + ( 6 π η a ω ) 2
δ ( ω ) = tan 1 ( 6 π η a ω k OT + k )
G ( ω ) = k ( ω ) 6 π a = k OT 6 π a ( A cos δ ( ω ) D ( ω ) 1 )
G ( ω ) = ω η ( ω ) = k OT 6 π a ( A sin δ ( ω ) D ( ω ) )
G ( ω ) = k OT 4 π a ( 3 2 sin θ + cos θ sin 3 θ ) ( A cos δ ( ω ) D ( ω ) 1 )
G ( ω ) = 3 k OT 16 a   sin θ ( A sin δ ( ω ) D ( ω ) )

Metrics