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Effects of Induced Electric Fields on Tissues and Cells

Sequin, Emily Katherine
http://rave.ohiolink.edu/etdc/view?acc_num=osu1403869854

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
Cancer remains a substantial health burden in the United States. Traditional treatments for solid malignancies may include chemotherapy, radiation therapy, targeted therapies, or surgical resection. Improved surgical outcomes coincide with increased information regarding the tumor extent in the operating room. Furthermore, pathological examination and diagnosis is bettered when the pathologist has additional information about lesion locations on the large resected specimens from which they take a small sample for microscopic evaluation. Likewise, cancer metastasis is a leading cause of cancer death. Fully understanding why a particular tumor becomes metastatic as well as the mechanisms of cell migration are critical to both preventing metastasis and treating it. This dissertation utilizes the complex interactions of induced electric fields with tissues and cells to meet two complementary research goals. First, eddy currents are induced in tissues using a coaxial eddy current probe (8mm diameter) in order to distinguish tumor tissue from surrounding normal tissue to address the needs of surgeons performing curative cancer resections. Measurements on animal tissue phantoms characterize the eddy current measurement finding that the effective probing area corresponds to about twice the diameter of the probe and that the specimen temperature must be constant for reliable measurements. Measurements on ten fresh tissue specimens from human patients undergoing surgical resection for liver metastases from colorectal cancer showed that the eddy current measurement technique can be used to differentiate tumors from surrounding liver tissue in a non-destructive, non-invasive manner. Furthermore, the differentiation between the tumor and normal tissues required no use of contrast agents. Statistically significant differences between eddy current measurements in three tissue categories, tumor, normal, and interface, were found across patients using a Tukey’s pairwise comparison. Moreover, the first eddy current image of the interface region between tumor and normal tissues is presented. Secondly, the effects of induced electric fields on cell motility are explored as cell motility plays an important role in both cancer metastasis and the healing of chronic wounds. Human keratinocyte migration in a wound healing assay was reduced by about 50% under the influence of a 1 Hz induced electric field with a maximum field strength of approximately 34.3 µV/cm. A modified Transwell migration assay was developed to study to migration of metastatic breast cancer cells under the influence of an induced electric field at 100 kHz and maximum field strength of 11.2 µV/cm. It was shown that low frequency, low magnitude, noncontact electric fields can overcome the effects of the chemoattractants SDF1a and EGF. This suggests a possible therapeutic benefit for the treatment of metastatic cancer with non-invasive, induced electric fields. In essence, this work has laid the foundation for exploring the use of non-contact, induced electric fields to study the properties of tissues and cells. These findings support the further development of eddy current technology into a tool useful in the operating room for surgeons seeking information on surgical margin quality. Furthermore, the modifications to standard migration assays offer new ways to study cell motility.
Vish Subramaniam (Advisor)
Shaurya Prakash (Advisor)
Carlos Castro (Committee Member)
Charles Hitchcock (Committee Member)
378 p.
Biomedical Engineering; Biomedical Research; Electromagnetics; Engineering; Experiments; Mechanical Engineering; Medical Imaging
Eddy Currents; electromagentics; induced electric fields; galvanotaxis; electrotaxis; cells motility; colorectal cancer; liver metastasis; margin determination; modelling induced electromagnetic fields;

Recommended Citations

Citations

  • Sequin, E. K. (2014). Effects of Induced Electric Fields on Tissues and Cells [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403869854

    APA Style (7th edition)

  • Sequin, Emily. Effects of Induced Electric Fields on Tissues and Cells. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1403869854.

    MLA Style (8th edition)

  • Sequin, Emily. "Effects of Induced Electric Fields on Tissues and Cells." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403869854

    Chicago Manual of Style (17th edition)

osu1403869854
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This open access ETD is published by The Ohio State University and OhioLINK.