A feasibility study for enrichment of highly aggressive cancer subpopulations by their biophysical properties via dielectrophoresis enhanced with synergistic fluid flow

Abstract

A common problem with cancer treatment is the development of treatment resistance and tumor recurrence that result from treatments that kill most tumor cells yet leave behind aggressive cells to repopulate. Presented here is a microfluidic device that can be used to isolate tumor subpopulations to optimize treatment selection. Dielectrophoresis (DEP) is a phenomenon where particles are polarized by an electric field and move along the electric field gradient. Different cell subpopulations have different DEP responses depending on their bioelectrical phenotype, which, we hypothesize, correlate with aggressiveness. We have designed a microfluidic device in which a region containing posts locally distorts channel of the electric field created by an AC voltage across a microfluidic channel and which forces cells toward the posts through DEP. This force is balanced with a simultaneous drag force from fluid motion that pulls cells away from the posts. We have shown that by adjusting the drag force, cells with aggressive phenotypes are influenced more by the DEP force and trap on posts while others flow through the chip unaffected. Utilizing single-cell trapping on cell-sized posts by a drag-DEP force balance, we show that separation of very similar cell subpopulations may be achieved, a result that was previously impossible with DEP alone. Separated subpopulations maintain high viability downstream, and remain in a native state, without fluorescent labeling. These cells can then be cultured to help select a therapy that kills aggressive subpopulations equally or better than the bulk of the tumor, mitigating resistance and recurrence.

On the recent developments of insulator‐based dielectrophoresis: A review

“…An important innovation to iDEP was proposed by the Davalos research group , they coined this new mode, i.e. contactless dielectrophoresis (cDEP).…”

The feasibility of using dielectrophoresis for isolation of glioblastoma subpopulations with increased stemness

“…Our results suggested that our microfluidic device is capable of sorting prostate tumor cells with stem like properties from other malignant phenotypes. In a consecutive study, we successfully demonstrated separation of aggressive ovarian cancer cells from their earlier stage progeny using dielectrophoresis . Other groups have demonstrated the alteration of dielectric properties of oral cancer cells with increased stem like properties .…”

“…As described previously , our microfluidic device uses contactless DEP to manipulate particles (Fig. A).…”

“…10x PBS is used as conductive fluid in the electrode channels. Avoiding direct contact with electrodes helps to maintain cell viability as well as electrode integrity . An array of 20‐micron posts are embedded in the main channel, introducing local inhomogeneity in the electric field near the posts.…”

“…To test our hypothesis, we used our previously developed microfluidic device to investigate the feasibility of using dielectrophoresis for enrichment of glioblastoma cells cultured under neurosphere assay . Our device has already been used to effectively separate different malignant and non‐malignant cell types . Cells cultured under neurosphere assays have been shown to have increased tumorigenicity in xenograft models, higher drug resistance as well as expression of stemness markers , hence they are considered a useful model of malignant cells with increased stem‐like properties .…”