title: Characterizing cell adhesion by using micropipette aspiration.
abstract: We have developed a technique to directly quantify cell-substrate adhesion force using micropipette aspiration. The micropipette is positioned perpendicular to the surface of an adherent cell and a constant-rate aspiration pressure is applied. Since the micropipette diameter and the aspiration pressure are our control parameters, we have direct knowledge of the aspiration force, whereas the cell behavior is monitored either in brightfield or interference reflection microscopy. This setup thus allows us to explore a range of geometric parameters, such as projected cell area, adhesion area, or pipette size, as well as dynamical parameters such as the loading rate. We find that cell detachment is a well-defined event occurring at a critical aspiration pressure, and that the detachment force scales with the cell adhesion area (for a given micropipette diameter and loading rate), which defines a critical stress. Taking into account the cell adhesion area, intrinsic parameters of the adhesion bonds, and the loading rate, a minimal model provides an expression for the critical stress that helps rationalize our experimental results.
authors.affiliation: Department of Mechanics, Hydrodynamics Laboratory (LadHyX), École Polytechnique, Palaiseau, France.
authors.forename: Brenna
authors.initials: B
authors.lastname: Hogan
authors.affiliation: Department of Mechanics, Hydrodynamics Laboratory (LadHyX), École Polytechnique, Palaiseau, France.
authors.forename: Avin
authors.initials: A
authors.lastname: Babataheri
authors.affiliation: Department of Aeronautics, Imperial College London, South Kensington, London, United Kingdom.
authors.forename: Yongyun
authors.initials: Y
authors.lastname: Hwang
authors.affiliation: Department of Mechanics, Hydrodynamics Laboratory (LadHyX), École Polytechnique, Palaiseau, France.
authors.forename: Abdul I
authors.initials: AI
authors.lastname: Barakat
authors.affiliation: Department of Mechanics, Hydrodynamics Laboratory (LadHyX), École Polytechnique, Palaiseau, France. Electronic address: julien.husson@ladhyx.polytechnique.fr.
authors.forename: Julien
authors.initials: J
authors.lastname: Husson
mesh_terms: D000818:Animals; D001011:Aorta; D001507:Beclomethasone; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003584:Cytological Techniques / Q000295:instrumentation* / Q000379:methods*; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D042783:Endothelial Cells / Q000502:physiology; D008853:Microscopy / Q000379:methods; D055616:Microtechnology; D011312:Pressure; D013314:Stress, Mechanical; D014741:Video Recording
chemical_list: D001507:Beclomethasone