Microfluidic biomechanical device for analyzing the deformation of cells in microchannels

Abstract

The physical forces to which living cells are most commonly exposed are fluid shear, pressure, and stretch. These mechanical stimulations influence the physiological and pathological condition of the organism, which induces many aspects of human health and disease. This study presents a new kind of microfluidic biomechanical device using poly(dimethylsiloxane) (PDMS) membrane deflection for stimulation and deformation of cell. To understand the biomechanical effects of cell deformation, mechanical stress is applied to cells with the deflection of the PDMS membrane between two microchannels, formed by multilayer soft lithography. The membrane functions as an on-off valve for closing the fluid channel and a loading membrane for applying a mechanical stress; the deflected membrane presses cells either directly or hydrostatically. As a demonstration of the feasibility of this microfluidic device, various applications are examined, including cell deformation under compression, reversible cell deformation, and cell viability assay. In addition, cell lysis was achieved by the compressive force through the deflection of membrane. As has been noted earlier, cellular mechanical properties related to the cell deformation are important for the understanding of the biomechanical effects with respect to cell. However, it is difficult to obtain the same viscoelastic parameters even for the same cell type under similar condition. The reasons why the measurement of the viscoelastic parameter is difficult are as follows: The theoretical model is overly simplified; Cells are characterized by complexity including inhomogeneity, anisotropy, no solidity, viscosity, and living organism. Therefore, the main focus is to develop a new and convenient biomechanical tool, capable of studying the integrity of cancer cells under excessive deformation; in particular, in comparison with those of normal cells. Here, it is well known that the amount of F-actin in cancer cells is fewer than ...