title: Whole cell quenched flow analysis.
abstract: This paper describes a microfluidic quenched flow platform for the investigation of ligand-mediated cell surface processes with unprecedented temporal resolution. A roll-slip behavior caused by cell-wall-fluid coupling was documented and acts to minimize the compression and shear stresses experienced by the cell. This feature enables high-velocity (100-400 mm/s) operation without impacting the integrity of the cell membrane. In addition, rotation generates localized convection paths. This cell-driven micromixing effect causes the cell to become rapidly enveloped with ligands to saturate the surface receptors. High-speed imaging of the transport of a Janus particle and fictitious domain numerical simulations were used to predict millisecond-scale biochemical switching times. Dispersion in the incubation channel was characterized by microparticle image velocimetry and minimized by using a horizontal Hele-Shaw velocity profile in combination with vertical hydrodynamic focusing to achieve highly reproducible incubation times (CV = 3.6%). Microfluidic quenched flow was used to investigate the pY1131 autophosphorylation transition in the type I insulin-like growth factor receptor (IGF-1R). This predimerized receptor undergoes autophosphorylation within 100 ms of stimulation. Beyond this demonstration, the extreme temporal resolution can be used to gain new insights into the mechanisms underpinning a tremendous variety of important cell surface events.
authors.affiliation: Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., 44227 Dortmund, Germany.
authors.forename: Ya-Yu
authors.initials: YY
authors.lastname: Chiang
authors.forename: Sina
authors.initials: S
authors.lastname: Haeri
authors.forename: Carsten
authors.initials: C
authors.lastname: Gizewski
authors.forename: Joanna D
authors.initials: JD
authors.lastname: Stewart
authors.forename: Peter
authors.initials: P
authors.lastname: Ehrhard
authors.forename: John
authors.initials: J
authors.lastname: Shrimpton
authors.forename: Dirk
authors.initials: D
authors.lastname: Janasek
authors.forename: Jonathan
authors.initials: J
authors.lastname: West
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057446:Hydrodynamics; D046210:Microfluidic Analytical Techniques / Q000379:methods*