Dielectrophoretic characterization of cells in a stationary nanoliter droplet array with generated chemical gradients

Abstract

A novel design of reusable microfluidic platform that generates a stationary nanoliter droplet array (SNDA) for cell incubation and analysis, equipped with a complementary array of individually addressable electrodes for each microwell is studied. Various solute concentration gradients were generated between the wells where dielectrophoresis (DEP) was used to characterize the effect of the gradients on the cell's response. The feasibility of generating concentration gradients and observation of DEP responses was demonstrated using a gradient of salts in combination with microparticles and viable cells. L1210 Lymphoma cells were used as the model cells in these experiments. Lymphoma cells' cross-over frequency (COF) decreased with increasing stress conditions. Specifically, a linear decrease in the cell COF was measured as a function of solution tonicity and blebbistatin dose. Lymphoma cells were incubated under a gradient of the chemotherapeutic agent doxorubicin (DOX), which led to saturation in the cell-COF response at 30 nM DOX, demonstrating the potential of the platform in screening of label-free drugs.

Dielectrophoretic characterization and isolation of jellyfish stinging capsules

“…After the electrode array was fabricated, a flexible silicone chamber of 1 mm in both diameter and depth (Grace BioLabs) was attached onto the electrode substrate. For separation of heterogeneous nematocyst capsule mixtures, a polydimethylsiloxane‐based microchannel (2 mm in width, 30 μm in depth) with an inclined electrode pair (20 μm in both width and spacing) were fabricated using soft‐lithography and standard photolithography .…”