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.

Measuring Cell Viscoelastic Properties Using a Microfluidic Extensional Flow Device

“…The aspiration pressure was applied using an air-filled syringe and determined using a home-made pressure sensor as described in Hogan et al (34). Aspiration pressure was increased from 0 to 10 kPa by incremental steps of 2 kPa.…”

Mechanical Criterion for the Rupture of a Cell Membrane under Compression

“…One to two days before an experiment, cells were cultured in thinbottomed Petri dishes (Fluorodish 35 mm, World Precision Instruments, Hitchin, United Kingdom). For experiments in which the cells were exposed to cytochalasin D, we used the same protocol as in Hogan et al (22): the cells were incubated for 30 min in a solution containing 1 mg/mL cytochalasin D from Zygosporium masonii (Sigma-Aldrich, Taufkirchen, Germany); the Petri dish was then rinsed and experiments were performed in fresh medium.…”

“…The deformation of the microindenter's cantilever is not modeled; rather, the cell indentation, Dz, is taken as the input. The endothelial cell is fixed on an infinitely rigid substrate to represent the focal adhesions that are observed experimentally on a glass substrate (22). The contact between the microindenter and the cell is implemented using the augmented Lagrangian method with a penalty factor of 10 5 , sufficient to prevent interpenetration.…”

Single-Cell Acoustic Force Spectroscopy: Resolving Kinetics and Strength of T Cell Adhesion to Fibronectin

“…Cell adhesion to the extracellular matrix (ECM) is central not only to tissue assembly and repair but also to immune surveillance and response (Ley et al, 2007). Adhesion kinetics and strength are currently measured with atomic force microscopy (AFM) (Benoit et al, 2000;Lehenkari and Horton, 1999;Li et al, 2003), surface plasmon resonance (SPR) technology (Kim et al, 2011), fluid-flow devices (Lu et al, 2004), shear-spinning disks (Boettiger, 2007;Friedland et al, 2009;García et al, 1998), centrifugation methods (Reyes and García, 2003), or micropipette aspiration (Hogan et al, 2015). Accurate measurements of cell adhesion kinetics and strength absolutely require large and well-defined datasets in order to grasp the heterogeneity in cell behavior of cell subsets and to capture rare events.…”