OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 3 — Feb. 1, 2010
  • pp: 2116–2126

Blinking Optical Tweezers for microrheology measurements of weak elasticity complex fluids

Giuseppe Pesce, Giulia Rusciano, and Antonio Sasso  »View Author Affiliations

Optics Express, Vol. 18, Issue 3, pp. 2116-2126 (2010)

View Full Text Article

Enhanced HTML    Acrobat PDF (609 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



Optical tweezers have become a powerful tool to explore the viscoelasticity of complex fluids at micrometric scale. In the experiments, the Brownian trajectories of optically confined microparticles are properly analysed to provide the viscous and elastic moduli G′ and G″. Nevertheless, the elastic response of the medium is inherently superimposed on the trap stiffness itself. Usually, this drawback is removed by subtracting the elastic trap contribution from the measured medium response. However, it is clear that when trap and medium elasticity become comparable this procedure is no longer reliable. Still, there exists a wide class of complex fluids that exhibit a low elasticity (diluted biopolymers, Boger fluids, etc) for which alternative experimental approaches would be desirable. Herein we propose a new method based on blinking optical tweezers. It makes use of two independent laser beams: the first is used to trap a single bead while the second one, of very weak power, acts as probe to monitor its position with a quadrant photodiode. The trap laser intensity is modulated on-off: when the laser is off the bead follows a free diffusion trajectory that, hence, leads to an estimation of G′ and G″ free of the influence of the trap. We have successfully applied this technique to highly-diluted hyaluronic acid solutions (c < 0.1 mg/ml) reaching to measure very weak G′ modulus (~ 0.01 Pa) in a wide range of frequencies.

© 2010 Optical Society of America

OCIS Codes
(160.5470) Materials : Polymers
(170.4520) Medical optics and biotechnology : Optical confinement and manipulation
(350.4855) Other areas of optics : Optical tweezers or optical manipulation

ToC Category:
Optical Trapping and Manipulation

Original Manuscript: November 4, 2009
Revised Manuscript: December 14, 2009
Manuscript Accepted: December 17, 2009
Published: January 19, 2010

Virtual Issues
Vol. 5, Iss. 4 Virtual Journal for Biomedical Optics

Giuseppe Pesce, Giulia Rusciano, and Antonio Sasso, "Blinking Optical Tweezers for microrheology measurements of weak elasticity complex fluids," Opt. Express 18, 2116-2126 (2010)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. J. D. Ferry, Viscoelastic Properties of Polymers (John Wiley, New York, 1980).
  2. R. G. Larson, The Structure and Rheology of Complex FLuids (University Press, Oxford, 1999).
  3. Y.-L. Wang and D. E. Discher, "Cell mechanics," Meth Cell Biol 83 (2008).
  4. A. C. De Luca, G. Volpe, A. M. Drets, M. I. Geli, G. Pesce, G. Rusciano, A. Sasso, and D. Petrov, "Real-time actin-cytoskeleton depolymerization detection in a single cell using optical tweezers," Opt. Express 15, 7922-7932 (2007). [CrossRef] [PubMed]
  5. G. Pesce, L. Selvaggi, A. Caporali, A. C. D. Luca, A. Puppo, G. Rusciano, and A. Sasso, "Mechanical changes of living oocytes at maturation investigated by multiple particle tracking," Appl. Phys. Lett. 95, 093702 (2009). [CrossRef]
  6. T. Waigh, "Microrheology of complex fluids," Rep. Prog. Phys. 68, 685-742 (2005). [CrossRef]
  7. M. Gardel, M. Valentine, and D. A. Weitz, Microscale Diagnostic Techniques (Springer, Oxford, 2005), chap. Microrheology.
  8. J. Liu, M. L. Gardel, K. Kroy, E. Frey, B. D. Hoffman, J. C. Crocker, A. R. Bausch, and D. A. Weitz, "Microrheology probes length scale dependent rheology," Phys Rev Lett 96, 118104 (2006). [CrossRef] [PubMed]
  9. A. Ashkin and J. M. Dziedzic, "Internal cell manipulation using infrared laser traps," Proc Natl Acad Sci USA 86, 7914-8 (1989). [CrossRef] [PubMed]
  10. M. Valentine, L. Dewalt, and H. OuYang, "Forces on a colloidal particle in a polymer solution: A study using optical tweezers," J Phys-Condens Mat 8, 9477-9482 (1996). [CrossRef]
  11. G. Pesce, A. Sasso, and S. Fusco, "Viscosity measurements on micron-size scale using optical tweezers," Rev. Sci. Inst. 76, 115105 (2005). [CrossRef]
  12. A. Buosciolo, G. Pesce, and A. Sasso, "New calibration method for position detector for simultaneous measurements of force constants and local viscosity in optical tweezers," Opt. Commun. 230, 357-368 (2004). [CrossRef]
  13. A. Bishop, T. Nieminen, N. Heckenberg, and H. Rubinsztein-Dunlop, "Optical microrheology using rotating laser-trapped particles," Phys Rev Lett 92, 198104 (2004). [CrossRef] [PubMed]
  14. A. Resnick, "Use of optical tweezers for colloid science," J Coll Int Sci 262, 55-59 (2003). [CrossRef]
  15. E. Furst, "Applications of laser tweezers in complex fluid rheology," Curr Opin Colloid In 10, 79-86 (2005). [CrossRef]
  16. R. R. Brau, J. M. Ferrer, H. Lee, C. E. Castro, B. K. Tam, P. B. Tarsa, P. Matsudaira, M. C. Boyce, R. D. Kamm, and M. J. Lang, "Passive and active microrheology with optical tweezers," J Opt A-Pure Appl Opt. 9, S103-S112 (2007). [CrossRef]
  17. G. Pesce, A. C. De Luca, G. Rusciano, P. A. Netti, S. Fusco, and A. Sasso, "Microrheology of complex fluids using optical tweezers: a comparison with macrorheological measurements," J Opt A-Pure Appl Opt 11, 034016 (2009). [CrossRef]
  18. J. Crocker, "Measurement of the hydrodynamic corrections to the brownian motion of two colloidal spheres," J. Chem. Phys. 106, 2837-2840 (1997). [CrossRef]
  19. E. Dufresne, T. Squires, M. Brenner, and D. Grier, "Hydrodynamic coupling of two brownian spheres to a planar surface," Phys. Rev. Lett . 85, 3317-3320 (2000). [CrossRef] [PubMed]
  20. R. D. Leonardo, J. Leach, H. Mushfique, J. M. Cooper, G. Ruocco, and M. J. Padgett, "Multipoint holographic optical velocimetry in microfluidic systems," Phys. Rev. Lett. 96, 134502 (2006). [CrossRef] [PubMed]
  21. R. L. Smith, G. C. Spalding, K. Dholakia, and M. P. MacDonald, "Colloidal sorting in dynamic optical lattices," J Opt. A-Pure Appl. Opt. 9, S134-S138 (2007). [CrossRef]
  22. G. Pesce, G. Volpe, A. C. D. Luca, G. Rusciano, and G. Volpe, "Quantitative assessment of non-conservative radiation forces in an optical trap," Europhys. Lett. 86, 38002 (2009). [CrossRef]
  23. S. Fusco, A. Borzacchiello, L. Miccio, G. Pesce, G. Rusciano, A. Sasso, and P. A. Netti, "High frequency viscoelastic behaviour of low molecular weight hyaluronic acid water solutions," Biorheology 44, 403-418 (2007).
  24. K. M. Addas, C. F. Schmidt, and J. X. Tang, "Microrheology of solutions of semiflexible biopolymer filaments using laser tweezers interferometry," Phys. Rev. E 70, 021503 (2004). [CrossRef]
  25. F. Gittes, B. Schnurr, P. Olmsted, F. MacKintosh, and C. Schmidt, "Microscopic viscoelasticity: Shear moduli of soft materials determined from thermal fluctuations," Phys Rev Lett 79, 3286-3289 (1997). [CrossRef]
  26. Y. Deng, J. Bechhoefer, and N. R. Forde, "Brownian motion in a modulated optical trap," J Opt. A-Pure Appl. Opt. 9, S256-S263 (2007). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited