Advances in Micropipette Aspiration: Applications in Cell Biomechanics, Models, and Extended Studies

Abstract

With five decades of sustained application, micropipette aspiration has enabled a wide range of biomechanical studies in the field of cell mechanics. Here, we provide an update on the use of the technique, with a focus on recent developments in the analysis of the experiments, innovative microaspiration-based approaches, and applications in a broad variety of cell types. We first recapitulate experimental variations of the technique. We then discuss analysis models focusing on important limitations of widely used biomechanical models, which underpin the urge to adopt the appropriate ones to avoid misleading conclusions. The possibilities of performing different studies on the same cell are also considered. Classical approach: Observing the cell shape during the aspiration processIn micropipette-aspiration experiments, a suction pressure DP is applied by connecting the micropipette (microcapillary) to an adjustable water reservoir (Fig. 1 a) or a pump. Cell changes (Fig. 1 c) are determined microscopically by means of image analysis (39). The suction pressure is given by the height difference between the tip of the micropipette and the top of the reservoir h and the specific weight of water rg: DP ¼ rgh. If there is a flow, the pressure drop along

Quantifying single‐platelet biomechanics: An outsider’s guide to biophysical methods and recent advances

“…Micropipette aspiration has been indispensable for membrane biophysicists interested in quantifying phase behavior, elasticity, and rupture tension of lipid bilayers . When applied to single cells, micropipette aspiration allows for measuring the biomechanical properties of single cells by observing cellular deformation upon application of defined suction pressure . It is one of the earliest biophysical tools used in single‐platelet manipulation and quantification of platelet biomechanics .…”

“…Micropipette aspiration (Figure A), as the name suggests, relies on suction of part of the single‐platelet membrane into a borosilicate glass micropipette (inner diameter of 0.5‐1.5 µm) connected to a micromanipulator by applying negative pressure in a stepwise manner. The subsequent change in the length of the platelet membrane aspirated into the micropipette over time is tracked by video microscopy (Figure B) . The data obtained from this type of experiment is then used to characterize material properties of a deforming cell using the Law of Laplace, which gives the relationship between the surface tension and pressure within a fluid drop that has a membrane with surface tension in it (Figure C).…”

“…Combining these two we arrive at the Law of Laplace, which gives the relationship between cell wall and its curvature 1/ R in terms with the surface tension n. Applying this to the critical Stage II during micropipette aspiration where R pro = L pro for radius of protrusion and that of cell we can effectively determination the surface tension n of the cell. (Figure modified from Gonzalez‐Bermudez et al)…”

“…[12][13][14] When applied to single cells, micropipette aspiration allows for measuring the biomechanical properties of single cells by observing cellular deformation upon application of defined suction pressure. 15 It is one of the earliest biophysical tools used in single-platelet manipulation and quantification of platelet biomechanics. 16 Micropipette aspiration (Figure 2A), as the name suggests, relies on suction of part of the single-platelet membrane into a borosilicate glass micropipette (inner diameter of 0.5-1.5 µm) connected to a micromanipulator by applying negative pressure in a stepwise manner.…”

“…The subsequent change in the length of the platelet membrane aspirated into the micropipette over time is tracked by video microscopy ( Figure 2B). 15,17 The data obtained from this type of experiment is then used to characterize material properties of a deforming cell using the Law of Laplace, which gives the relationship between the surface tension and pressure within a fluid drop that has a membrane with surface tension in it ( Figure 2C).…”