Enhanced cell viability and cell adhesion using low conductivity medium for negative dielectrophoretic cell patterning

Abstract

Negative dielectrophoretic (n-DEP) cell manipulation is an efficient way to pattern human liver cells on micro-electrode arrays. Maintaining cell viability is an important objective for this approach. This study investigates the effect of low conductivity medium and the optimally designed microchip on cell viability and cell adhesion. To explore the influence of conductivity on cell viability and cell adhesion, we have used earlier reported dielectrophoresis (DEP) buffer with a conductivity of 10.2 mS/m and three formulated media with conductivity of 9.02 (M1), 8.14 (M2), 9.55 (M3) mS/m. The earlier reported isotonic sucrose/dextrose buffer (DEP buffer) used for DEP manipulation has the drawback of poor cell adhesion and cell viability. A microchip prototype with well-defined positioning of titanium electrode arrays was designed and fabricated on a glass substrate. The gap between the radial electrodes was accurately determined to achieve good cell patterning performance. Parameters such as dimension of positioning electrode, amplitude, and frequency of voltage signal were investigated to optimize the performance of the microchip.

Characterization of biomechanical properties of cells through dielectrophoresis-based cell stretching and actin cytoskeleton modeling

“…DOX (Sigma-Aldrich) was used to alter the biological properties of NB4 cells, and NB4-DOX cells were cultured in 0.05 μM DOX medium for 96 h. All cells were cultured in a humidified incubator with 5% CO 2 at 37 °C. To conduct DEP-based cell stretching experiments, the cells were resuspended in an isotonic buffer medium consisting of 8.5% sucrose, 0.3% dextrose, and 20 mg/L CaCl 2 [37]. For confocal fluorescence imaging, the cells were fixed with 4% paraformaldehyde and permeabilized with 0.5% Triton X-100 for 10 min at room temperature; afterward, the actin cytoskeleton of NB4 cells was stained with rhodamine-phalloidin (Invitrogen) for 10 min.…”

“…Finite element software COMSOL Multiphysics was used to simulate the distribution of electric field for computing the DEP force acting on the cells. The stretching experiment was completed within 30 min in order to minimize the threat to the survival of the cells [37]. …”

Single living cell manipulation and identification using microsystems technologies

“…Cells of interest are targeted by the suitable selected frequencies 20,26,27 . The cells seen in the lower left part of the figure will not cross the comb-like electrode and will be directed to flow to the selected outlet.…”

“…For separation as mentioned above, cells are suspended in a media with a mixture of water and sucrose/dextrose 20,26,27 . For cell detection, since the CP of the solution of sucrose/dextrose is very close to that of the cells, a mixture of glycerol with trypsin (water soluble triglyceride) is used in experiments due to its very low dielectric constant at RF frequencies.…”

Magnetic Assembly of Tissue Surrogates

“…Both methods typically require a solution of low ionic strength for operation. Such a condition is not optimal for cell growth and requires improvement 38 . In contrast, the use of magnetic force offers the advantage of contactless control of cell movement in regular culture medium, minimizing cell damage.…”