Title page for ETD etd-02142012-134924

Type of Document Master's Thesis
Author Rojas, Andrea Diane
URN etd-02142012-134924
Title Particle Manipulation Using Electric Field Gradients in Microdevices
Degree Master of Science
Department Materials Science and Engineering
Advisory Committee
Advisor Name Title
Davalos, Rafael V. Committee Chair
Aning, Alexander O. Committee Member
Schmelz, Eva M. Committee Member
Whittington, Abby R. Committee Member
  • Electrokinetics
  • Bacterial Cellulose
  • Breast Cancer
  • Contactless Dielectrophoresis
Date of Defense 2012-02-01
Availability restricted
Electrokinetics is a family of effects that induces motion of a liquid or a particle within a liquid in response to an external electric field. Using the intrinsic electrical properties of bacteria and of breast cancer cells, electrokinetics can be used to manipulate these particles for two different types of applications: tissue engineering and breast cancer detection. The first application studied the effects of electric fields on bacteria cells as well as calcium ions to potentially create a meniscus scaffold with hydroxyapatite ends for anchoring. In response to the electric field, calcium ions were able to deposit locally and simultaneously with cellulose growth. Bacteria cells were also studied to determine their response under an AC field. At low frequencies, bacteria demonstrated controlled movement caused by electroosmosis and dielectrophoresis with a net motion caused by a dielectrophoretic force.

In the second application, the separation capabilities of different stages of breast cancer cells from the same cell line were tested using contactless dielectrophoretic (cDEP) devices. The electric field gradients in cDEP devices were altered to optimize selectivity and to determine an estimated membrane capacitance for each. From the results, the membrane capacitance of the early to intermediate stages proved to be very similar; however, late stage breast cancer cells have potential in being separated from early and intermediate stages.

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