Exploiting Clausius-Mossotti Factor to Isolate Stages of Human Breast Cancer Cells: Theory and Experiment

Abstract

This work demonstrates the ability of contactless dielectrophoresis (cDEP) for isolation of breast cancer cell stages. The ability to selectively concentrate breast tumor cells from a non-transformed or normal cell population is the key to successfully detecting tumors at an early stage of growth and treating transformed cells before they proliferate. Since all cell types have a unique molecular composition it is expected that their dielectrophoretic properties are also unique. DEP force is dependent on the frequency and magnitude of the applied field, as well as a particle's size and electric properties. Specifically, the Clausius-Mossotti factor in the DEP force equation determines a specific cell type's interaction with the electric field and the DEP force response. Cell properties affecting this parameter were investigated numerically and experimentally. MCF10A, MCF7, and MDA-MB231 human breast cancer cells were used to represent early, intermediate, and late staged breast cancer respectively. Experiments were conducted at 0.02ml/hr with applied voltages of 20Vrms, 25Vrms, 30Vrms, 35Vrms, 40Vrms and 50Vrms (n=8). Frequency measurements were recorded for the initial onset of DEP force and when 90% trapping was obtained. The trapping frequency ranges for each cell were distinct from one another with the least amount of overlap between the MCF10A cells and MDA-MB231cells. The MCF7 cell line had, on average, the smallest trapping region at each applied voltage, and fell in between the normal and late staged cells' trapping frequency ranges. Voltages of 20Vrms to 30Vrms were found the most efficient for cell isolation.