(177g) Measuring Electrical Properties of Cancer Cells Via Electrorotation

Authors: 
Lannin, T., Cornell University
Kirby, B. J., Cornell University
Thege, F., Cornell University
Huang, C., Cornell University
Gruber, C., Cornell University

Measuring Electrical Properties of Cancer Cells via
Electrorotation

Circulating tumor cells are cancer cells that can be
extracted from patient blood, and their capture provides a window through which
we can examine the progression of cancer in real time with minimal
invasiveness. As these cells circulate, they are exposed to a variety of
physical and chemical stimuli that we hypothesize change the structure and
composition of the membrane, nucleus, and cytoplasm. For example, the
morphology of the cell membrane is sensitive to the deprivation of growth
factors or the acquired resistance to Gemcitabine chemotherapy. Because these cellular
changes are dynamic, it is critical to characterize this process in order to
effectively capture and analyze the cells.

We have conducted experiments to understand how stimuli that
cancer cells experience in circulation affect their electrical phenotype in
order to 1) gain insights into cancer cell membrane physiology, which will help
reveal connections between primary tumors, circulating cells, and metastases,
and 2) inform better cell capture with electrokinetic techniques, such as
dielectrophoresis (DEP), which will enable new sets of genetic and other
analyses that require higher purity than the current state of the art in cell
capture provides.

Although DEP is suitable for applying forces to cells for
separations, electrorotation, a technique related to DEP in which torques are
applied to cells in response to rotating electric fields, is more suitable for
experimental characterization of cells. An electrorotation spectrum gives
complete information necessary to infer a DEP spectrum and extract electrical
properties such as the cytoplasmic conductivity and membrane specific
capacitance.

We present data on changes in pancreatic cancer cell lines'
electrorotation spectra after serum starvation, a stress known to alter cell
membrane morphology and cytoplasmic contents. (See attached figure for
electrorotation spectra of serum-starved and serum-supplemented BxPC3
pancreatic cancer cells). We also present electrorotation spectra of a
Gemcitabine-resistant pancreatic cancer cell subclone, which we compare to
their Gemcitabine-naïve counterparts.