Cell Separation on Microfabricated Electrodes Using Dielectrophoretic/Gravitational Field-Flow Fractionation

Abstract

Dielectrophoretic/gravitational field-flow fractionation (DEP/G-FFF) was used to separate cultured human breast cancer MDA-435 cells from normal blood cells mixed together in a sucrose/dextrose medium. An array of microfabricated, interdigitated electrodes of 50 microns widths and spacings, and lining the bottom surface of a thin chamber (0.42 mm H x 25 mm W x 300 mm L), was used to generate DEP forces that levitated the cells. A 10-microL cell mixture sample containing approximately 50,000 cells was introduced into the chamber, and cancerous and normal blood cells were levitated to different heights according to the balance of DEP and gravitational forces. The cells at different heights were transported at different velocities under the influence of a parabolic flow profile that was established in the chamber and were thereby separated. Separation performance depended on the frequency and voltage of the applied DEP field and the fluid-flow rate. It took as little as 5 min to achieve cell separation. An analysis of the DEP/G-FFF results revealed that the separation exploited the difference in dielectric and density properties between cell populations. The DEP/G-FFF technique is potentially applicable to many biological and biomedical problems, especially those related to microfluidic systems.

Microfabrication and test of a three-dimensional polymer hydro-focusing unit for flow cytometry applications

“…Many research efforts have been made in developing different types of micro-cytometry systems [1][2][3][4][5][6][7][8][9][10][11][12]. Micro-sized flow cytometry devices and components offer many potential benefits, including the ability to reduce device and sample sizes, development of low cost, single-use disposable devices, and improved device portability for field use along with low consumption of sample and buffer fluids, and reduction in the biohazard risk level.…”

Cell Separation by Dielectrophoretic Field-flow-fractionation

“…8,15,21 12,17,[22][23][24] differential DEP forces can be applied to drive their separation into purified cell subpopulations. 14,[16][17][18][19][20][25][26] A recently developed technique, dielectrophoretic-field-flow fractionation (DEP-FFF), has been demonstrated to exhibit a high and electrically controllable discrimination for cell separation. [18][19][20] 27 DEP forces produced by microelectrodes are used to levitate cells in a thin chamber to equilibrium heights where sedimentation forces balance the vertical DEP force components (Figure 1).…”

Automated electrorotation shows electrokinetic separation of pancreatic cancer cells is robust to acquired chemotherapy resistance, serum starvation, and EMT

“…These values are higher than those from ROT experiments of T lymphocytes and MDA321 breast cancer cells (64 and 52) reported by Becker et al 16 and used by many subsequent studies. 14,17,18,51 The dielectric increment of glycine in water is positive, 23,52 whereas the dielectric increment of salts is negative, 23,53 so their competing effect on the permittivity of cytoplasm is unclear. The concentration of either type of solute could be different in cells with a highly dysregulated growth and metabolism.…”

“…Using DEP as the only separation mechanism has led to some success in CTC enrichment. [14][15][16] A proof-of-concept hybrid DEP-immunoaffinity device has shown promise of further improving capture. [17][18][19] Careful device design and frequency selection can attract CTCs while repelling contaminating white blood cells, and simulations have predicted capture efficiency increases of up to 400%.…”