title: A microfluidic technique to probe cell deformability.
abstract: Here we detail the design, fabrication, and use of a microfluidic device to evaluate the deformability of a large number of individual cells in an efficient manner. Typically, data for ~10(2) cells can be acquired within a 1 hr experiment. An automated image analysis program enables efficient post-experiment analysis of image data, enabling processing to be complete within a few hours. Our device geometry is unique in that cells must deform through a series of micron-scale constrictions, thereby enabling the initial deformation and time-dependent relaxation of individual cells to be assayed. The applicability of this method to human promyelocytic leukemia (HL-60) cells is demonstrated. Driving cells to deform through micron-scale constrictions using pressure-driven flow, we observe that human promyelocytic (HL-60) cells momentarily occlude the first constriction for a median time of 9.3 msec before passaging more quickly through the subsequent constrictions with a median transit time of 4.0 msec per constriction. By contrast, all-trans retinoic acid-treated (neutrophil-type) HL-60 cells occlude the first constriction for only 4.3 msec before passaging through the subsequent constrictions with a median transit time of 3.3 msec. This method can provide insight into the viscoelastic nature of cells, and ultimately reveal the molecular origins of this behavior.
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles; Department of Aerospace and Mechanical Engineering, University of Notre Dame.
authors.forename: David J
authors.initials: DJ
authors.lastname: Hoelzle
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles; Molecular Imaging Center, University of Southern California.
authors.forename: Bino A
authors.initials: BA
authors.lastname: Varghese
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles.
authors.forename: Clara K
authors.initials: CK
authors.lastname: Chan
authors.affiliation: Department of Integrative Biology and Physiology, University of California, Los Angeles; rowat@ucla.edu.
authors.forename: Amy C
authors.initials: AC
authors.lastname: Rowat
mesh_terms: D048430:Cell Shape / Q000502:physiology; D003584:Cytological Techniques / Q000295:instrumentation* / Q000379:methods*; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004867:Equipment Design; D018922:HL-60 Cells; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon