Microfluidic Mechanotyping of a Single Cell with Two Consecutive Constrictions of Different Sizes and an Electrical Detection System

Abstract

The mechanical properties of a cell, which include parameters such as elasticity, inner pressure, and tensile strength, are extremely important because changes in these properties are indicative of diseases ranging from diabetes to malignant transformation. Considering the heterogeneity within a population of cancer cells, a robust measurement system at the single cell level is required for research and in clinical purposes. In this study, a potential microfluidic device for high-throughput and practical mechanotyping were developed to investigate the deformability and sizes of cells through a single run. This mechanotyping device consisted of two different sizes of consecutive constrictions in a microchannel and measured the size of cells and related deformability during transit. Cell deformability was evaluated based on the transit and on the effects of cytoskeleton-affecting drugs, which were detected within 50 ms. The mechanotyping device was able to also measure a cell cycle without the use of fluorescent or protein tags.

Label-Free Cancer Stem-like Cell Assay Conducted at a Single Cell Level Using Microfluidic Mechanotyping Devices

“…As shown in Figure S1, the mean diameters of 100 cancer cells were 14.8 ± 1.2 μm for HT29 cells, 15.2 ± 1.5 μm for Caco-2 cells, 15.4 ± 1.6 μm for HeLa cells, 16.4 ± 2.0 μm for MDA-MB-231 cells, and 10.8 ± 1.1 μm for Jurkat cells. Notably, these values were found to be comparable to those of several previous reports. ,, …”

“…Notably, these values were found to be comparable to those of several previous reports. 37,38,43 To investigate cell deformability, we prepared three different widths of the rear constriction (6, 8, and 10 μm) with a length of 30 μm. For cell size measurement at the front constriction, all of them had the same dimension, 20 μm wide and 30 μm long.…”

“…The simultaneous detection system consisting of an ionic current and microscopic observation was originally developed in our group; the detailed setup of this system is described elsewhere. − The microfluidic channels were connected to components through silver wires, and the whole electrical circuit is depicted in Figure . Prior to the electrophoresis and the ionic current measurements, the variable-resistance element in the detection circuit was adjusted to 0 A and prevented current flow into the detection circuit.…”

“…In this study, we investigated the mechanical properties of HT29 cells, which are known to be a heterogeneous cell line possessing both multipotency and self-renewal abilities, − using microfluidic devices, biochemical markers of CD44 and CD133 expression, and ALDH activity. Previously, we developed a method to measure cell deformability, which enabled us to successfully assess the cell cycle and detect circulating cancer cells (CTCs) in whole blood . To measure cell deformability, we first examined the width of the rear constriction by using the current measurement method and a microfluidic device.…”

Oxide nanowire microfluidics addressing previously-unattainable analytical methods for biomolecules towards liquid biopsy

“…Thus, an essential requirement is a highly sensitive method that can detect low levels of biomolecular analytes. Through the convergence of engineering and life science, the past decades have been witnessing significant progress in advanced biological sensors, [89][90][91][92][93][94][95][96] in a wide range of areas, including genomics, proteomics, biomedical diagnostics, and drug discovery. The regime of molecular sizes mostly lies in the nanometer scale, necessitating that their detection capability be nanoscale.…”