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

Abstract

The mechanical phenotype of cells is an intrinsic property of individual cells. In fact, this property could serve as a label-free, non-destructive, diagnostic marker of the state of cells owing to its remarkable translational potential. A microfluidic device is a strong candidate for meeting the demand of this translational research as it can be used to diagnose a large population of cells at a single cell level in a high-throughput manner, without the need for off-line pretreatment operations. In this study, we investigated the mechanical phenotype of the human colon adenocarcinoma cell, HT29, which is known to be a heterogeneous cell line with both multipotency and self-renewal abilities. This type of cancer stem-like cell (CSC) is believed to be the unique originators of all tumor cells and may serve as the leading cause of cancer metastasis and drug resistance. By combining consecutive constrictions and microchannels with an ionic current sensing system, we found a high heterogeneity of cell deformability in the population of HT29 cells. Moreover, based on the level of aldehyde dehydrogenase (ALDH) activity and the expression level of CD44s, which are biochemical markers that suggest the multipotency of cells, the high heterogeneity of cell deformability was concluded to be a potential mechanical marker of CSCs. The development of label-free and non-destructive identification and collection techniques for CSCs has remarkable potential not only for cancer diagnosis and prognosis but also for the discovery of a new treatment for cancer.

Performance-enhanced clogging-free viscous sheath constriction impedance flow cytometry

“…Estimates of cell biomechanical parameters can then be obtained with electrical measurements. 26–30 On the other hand, in the present work, cell mechanical deformation is not pursued but cell electrical property measurement, and the SA is larger than the beads/cells. 31–33…”

“…Estimates of cell biomechanical parameters can then be obtained with electrical measurements. [26][27][28][29][30] On the other hand, in the present work, cell mechanical deformation is not pursued but cell electrical property measurement, and the SA is larger than the beads/cells. [31][32][33] However, this MC configuration is limited by a technical trade-off between sensitivity and throughput, i.e., the narrow channel in pursuit of sensitivity poses the risk of channel clogging.…”

“…[12][13][14][15][16][17][18] So far, IFC techniques have made progress in high-content measurement of single-cell biophysical multi-modal fingerprints including cell size, 19 shape, 20 and electrical [21][22][23] and mechanical properties. 24,25 Most of the IFC techniques use a narrow channel [26][27][28][29][30][31][32][33] as mechanical constriction (MC) to decrease the sensing aperture (SA), which matches the cell size to achieve high detection sensitivity. Frequently, MC refers to impedance cytometers housing a "constriction channel", whose dimensions are smaller than that of the cells under investigation, so that a mechanical deformation of the cells is induced.…”

“…Most of the IFC techniques use a narrow channel 26–33 as mechanical constriction (MC) to decrease the sensing aperture (SA), which matches the cell size to achieve high detection sensitivity. Frequently, MC refers to impedance cytometers housing a “constriction channel”, whose dimensions are smaller than that of the cells under investigation, so that a mechanical deformation of the cells is induced.…”

Droplet Detection and Sorting System in Microfluidics: A Review

“…In the past decades, microfluidic systems have been widely used in the fields of drug discovery [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ], single-cell studies [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ], medical diagnostics [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], and tissue engineering [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. Droplet microfluidics, as one of the major branches of microfluidic techniques, exhibits great promise in their ability to conduct high-throughput assays for a broad range of life science applications, including single-cell sequencing, antibody and drug discovery [ 34 , 35 ], cell assays, and pathogen screening [ 36 , 37 ].…”