title: Microfluidics-based side view flow chamber reveals tether-to-sling transition in rolling neutrophils.
abstract: Neutrophils rolling at high shear stress (above 6 dyn/cm(2)) form tethers in the rear and slings in the front. Here, we developed a novel photo-lithographically fabricated, silicone(PDMS)-based side-view flow chamber to dynamically visualize tether and sling formation. Fluorescently membrane-labeled mouse neutrophils rolled on P-selectin substrate at 10 dyn/cm(2). Most rolling cells formed 5 tethers that were 2-30 μm long. Breaking of a single tether caused a reproducible forward microjump of the cell, showing that the tether was load-bearing. About 15% of all tether-breaking events resulted in slings. The tether-to-sling transition was fast (<100 ms) with no visible material extending above the rolling cell, suggesting a very low bending modulus of the tether. The sling downstream of the rolling cell aligned according to the streamlines before landing on the flow chamber. These new observations explain how slings form from tethers and provide insight into their biomechanical properties.
authors.affiliation: La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Marki
authors.affiliation: Department of Physics and University of California San Diego, La Jolla, CA, USA.
authors.forename: Edgar
authors.initials: E
authors.lastname: Gutierrez
authors.affiliation: La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Mikulski
authors.affiliation: Department of Physics and University of California San Diego, La Jolla, CA, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Groisman
authors.affiliation: La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA.|Department of Bioengineering, University of California San Diego, La Jolla, CA, USA.
authors.forename: Klaus
authors.initials: K
authors.lastname: Ley
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D002465:Cell Movement; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D036904:Leukocyte Rolling; D051379:Mice; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D018613:Microscopy, Confocal; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*; D019007:P-Selectin / Q000378:metabolism
chemical_list: D004129:Dimethylpolysiloxanes; D019007:P-Selectin; C013830:baysilon