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Aranda-Espinoza, Helim

Helim Aranda-Espinoza
Associate Professor
Associate Chair and Director of Graduate Studies
3138 Jeong H. Kim Engineering Building
Lab Description

News About This Professor

Research Interests 

Chemical and biological engineering, soft condensed matter, biomechanics and biopolymers.


Ph.D., Universidad de San Luis Potosi, Mexico, 1998


  • BIOE689M: Cell Motility. Fischell Department of Bioengineering. Fall 2007. University of Maryland.
  • BIOE605: Laboratory Rotation I. Fischell Department of Bioengineering. Fall 2007.
  • BIOE608: Bioengineering Seminar Series. Fischell Department of Bioengineering. Fall 2007.
  • Course: Biophysics of Cell Motility. XX Meeting on the Science and Technology of Complex Fluids. Physics Institute, University of San Luis Potosi, Mexico. June 25-29, 2007. 
  • ENCH300: Chemical Process Thermodynamics. Department of Chemical and Biomolecular Engineering. Spring 2007. University of Maryland.
  • BIOE689M: Cell Motility. Fischell Department of Bioengineering. Fall 2006. University of Maryland.
  • ENCH620: Methods of Engineering Analysis. Department of Chemical and Biomolecular Engineering. Fall 2005. University of Maryland.

For a complete list of courses taught, please visit Professor Aranda-Espinoza's web site

Current Research Projects 

The Cell Biophysics Laboratory is primarily concerned with the spreading, motility, and division of cells on flexible substrates.What is the effect of the mechanical environment on cells? Current and recent research thrusts include:

  • Cell adhesion controls and mitosis
  • Cell spreading: The role of Filopedia in symmetry breaking
  • Cell–cell interaction; or, the importance of being a good neighbor
  • Cholesterol effect on cell adhesion and mechanics
  • Morphology of vesicles as a function of lipid content
  • Cholesterol homeostasis: from vesicle to cellular funciton

Selected Publications 


Neutrophil Spreading: From Touchdown to First Steps.. With K. Sengupta, Lee Smith, P. Janmey, and D. Hammer.  Biophys. J. (In Press). Spreading of neutrophils is explored using interference microscopy.  Neutrophils show anisotropic spreading with adhesion dependent growth.

Interplay Between Shear Stress and Adhesion Ligands on the Locomotion of Human Neutrophils.  With Lee Smith, J. Haun, and D. Hammer. Biophys. J. (In Press). The effect of flow and adhesive substrates on neutrophil motility is explored in this paper.

Cholesterol Depletion Increases Membrane Stiffness of Aortic Endothelial Cells. With F. Byfield, V. Romanenko, G. Rothblat, and I. Levitan. Biophys. J. 87 (2004) 3344. Is cholesterol good for you?


Shapes of Mixed Phospholipid Vesicles. With G. Paredes and A. Maldonado Arce.  J. Biol. Phys. Description of the morphology of vesicles as a function of the membrane lipid mixture. Cylindrical vesicles form coils when an external perturbation is imposed.

Pore Stability and Dynamics in Polymer Membranes. With H. Bermudez, D. A. Hammer, and D. E. Discher.  Europhys. Lett. 64 (2003) 550. Membrane thickness allows to control the dynamics of pores, from slow growing kinetically trapped holes.

Electromechanical Limits of Polymersomes. With H. Bermudez, F. S. Bates, and D. E. Discher, Phys. Rev. Lett. 87 (2001) 208301. A study on the stability of vesicles as a function of membrane thickness. Thicker is tougher  but thinner is more functional.


Flexibility Transitions and Looped Adsorption of Worm-like Chains. With P. Dalhaimer, O. I. Wagner, J.-F. Leterrier, P. A. Janmey, and D. E. Discher. J. of Polymer Sci. B 43 (2005) 280. Polymer adsorption to 2D substrates modifies the persistence length.

Elongation and Fluctuations of Semi-flexible Polymers in a Nematic Solvent. With Z. Dogic, J. Zhang, A.W.C. Lau, P. Dalhaimer, D. Discher, P. A. Janmey, R.D. Kamien, T.C. Lubensky, and A. Yodh. Phys. Rev. Lett. 92 (2004) 125503. Aligning the tracks!

Domain Unfolding in Neurofilament Sidearms: Effects of Phosphorylation and ATP. With P. Carl, P. Janmey, J. F. Leterrier, and D. E. Discher, FEBS Letters 531 (2002) 397. An electrostatic bridge is responsible for the large force required to fold a charged polymer.


Electrostatically Induced Undulations of Lamellar DNA-Lipid Complexes. With H. Schiessel. European Phys. J. E 5 (2001) 499.

Interaction Between Inclusions Embedded in Membranes. With A. Berman, N. Dan, P. Pincus, and S. Safran, Biophys. J. 71 (1996) 648.

Static Structure of the Two-Dimensional Hard-Disk Plus Yukawa Fluid. With M. Medina Noyola and J.L. Arauz Lara, J. Chem. Phys. 99 (1993) 5462.


Cholesterol Depletion Constrains Mechanical Deformation of Aortic Endothelial Cells. With F. Byfield, V. Romanenko, G. Rothblat, and I. Levitan. Proceedings of the IASTED International Conference on Biomechanics. (2003) 86.

Hydrodynamics of Polymer Membranes. With P. Dalhaimer, F. S. Bates,  and D. E. Discher.  Comptes Rendus de l’Academie des Sciences – Series IV Physics-Astrophysics 4 (2003) 251.

Electrostatic Repulsion of Positively Charged Vesicles and Negatively Charged Objects. With Yi Chen, N. Dan, T. C. Lubensky, P. Nelson, L. Ramos, and D.A. Weitz, Science 285 (1999) 394.

Structure Factor of Flexible Membranes. With D. Lavallee, Europhys. Lett. 43 (1998) 355.

Virus Cell-Fusion. With S. Aranda. II Mexican Symposium on Medical Physics. American Institute of Physics Conference Proceedings 440, 211 (1998).

Structure and Self-diffusion in a Model Two-dimensional Brownian Liquid. With M. Carbajal-Tinoco, E. Urrutia-Banuelos, J.L.Arauz-Lara, M. Medina-Noyola, and J. Alejandre, J. of Chem. Phys. 101 (1994) 10925.

Related News 

Fisher Co-Edits Book on Tissue Engineering
Tissue Engineering: Principles and Practices available from CRC Press. July 3, 2013

4 BioE Grad Students Win UMD Distinguished TA Awards
Ferlin, Ganesan, Lin and Manthe recognized by Center for Teaching Excellence. May 22, 2013

2012-2013 BioE Undergraduate Awards
Exceptional students recognized at annual ceremony. April 9, 2013

Chen Bioimaging Research Wins Prestigious NSF CAREER Award
Grant supports improvements to neural imaging and image-guided neurosurgery. November 20, 2012

Merrill Presidential Scholars Honored
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Undergraduates Present Work at APS March Meeting
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White's Research Wins Prestigious NSF CAREER Award
Inkjet-printed paper biosensors will reduce cost of diagnosing epidemic pathogens. February 3, 2012

Novel Biophysical Models Help Explain Mechanics of Cardiovascular Disease
Stroka, Aranda-Espinoza publish results in Blood. September 19, 2011

Aranda-Espinoza, Hsieh Promoted
BioE faculty members promoted to Associate Professor, receive tenure. August 30, 2011

$1.35M For New Study of Cell Migration
Aranda-Espinoza wins Human Frontier Science Program research grant. August 25, 2011

Seog Research Wins NSF CAREER Award
Novel methods will explain peptide and nanofiber behavior at molecular level. January 18, 2011

Stroka Wins NIH Grant for Cardiovascular Research
Ruth L. Kirschstein National Research Service Award will fund work on the biophysics of cell transmigration through the vascular endothelium. January 19, 2010

ResearchFest 2006-2007
ChBE, BioE students share research, hold poster contest. April 20, 2007

Aranda-Espinoza Wins NSF CAREER Award
Award to fund research in Cell Biophysics Laboratory. March 2, 2007