Microfluidic Shear Devices for Quantitative Analysis of Cell Adhesion

Abstract

We describe the design, construction, and characterization of microfluidic devices for studying cell adhesion and cell mechanics. The method offers multiple advantages over previous approaches, including a wide range of distractive forces, high-throughput performance, simplicity in experimental setup and control, and potential for integration with other microanalytic modules. By manipulating the geometry and surface chemistry of the microdevices, we are able to vary the shear force and the biochemistry during an experiment. The dynamics of cell detachment under different conditions can be captured simultaneously using time-lapse videomicroscopy. We demonstrate assessment of cell adhesion to fibronectin-coated substrates as a function of the shear stress or fibronectin concentration in microchannels. Furthermore, a combined perfusion-shear device is designed to maintain cell viability for long-term culture as well as to introduce exogenous reagents for biochemical studies of cell adhesion regulation. In agreement with established literature, we show that fibroblasts cultured in the combined device reduced their adhesion strength to the substrate in response to epidermal growth factor stimulation.

Transient Convection, Diffusion, and Adsorption in Surface-Based Biosensors

“…Such biosensors are used in diverse areas, such as for DNA hybridization, 1,2 chemiluminescence detection, 3 and cell attachment and release from surfaces. 4 From a theoretical viewpoint, similar physics also occur in other systems, such as protein microarrays. 5 Theoretical research, related to biosensor applications, typically attempts to include novel mechanisms, such as the ac electrothermal (ACET) effect, 6 or aims at developing analytical and semianalytical models for better data interpretation.…”

Predicting how cells spread and migrate

“…31 Cellmatrix adhesion strength may depend on the contact area between the cell and its adhesive substrate (i.e., cell spreading size), 32 cell mechanics and contractility, 33 the level of expression and activation of adhesion molecules (integrins), 34 and presumably, their extent of clustering into focal adhesions, and the affinity of individual integrin molecules with their matrix molecules. Current experimental approaches such as estimation of cell spreading area or fraction of remaining adherent cells after centrifugation 35 or shearing in microfluidic devices, 36 and measurement of single-bond rupture force by atomic force microscopy 37,38 have severe limitations, since they do not decipher the various contributors to global cell adhesion, that are intertwined with each other, and may indirectly or directly influence cell-matrix adhesion.…”

Label-free, microfluidic separation and enrichment of human breast cancer cells by adhesion difference

“…[22][23][24][25] A microfluidic system is advantageous for analysis of cell adhesion in various aspects because of small sample consumption, use of multiple parameters, and generation of large shear stress. 26,27 By integrating nanostructured surfaces with a microfluidic system, we herein devise a simple, label-free cell separation and enrichment scheme based on standard soft lithography and microfluidics protocol. The PDMS microfluidic device consists of four branch channels, each of which contains flat or polymeric nanostructures on the bottom (400 nm pillars, 400 nm perpendicular, and 400 nm parallel lines, respectively) to increase the difference in cell adhesion.…”