The Effect of Stiffness on Cancer Cell Contact Guidance

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Koelbl, Joseph
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Symposium on Undergraduate Research and Creative Expression
Iowa State University Conferences and Symposia

The Symposium provides undergraduates from all academic disciplines with an opportunity to share their research with the university community and other guests through conference-style oral presentations. The Symposium represents part of a larger effort of Iowa State University to enhance, support, and celebrate undergraduate research activity.

Though coordinated by the University Honors Program, all undergraduate students are eligible and encouraged to participate in the Symposium. Undergraduates conducting research but not yet ready to present their work are encouraged to attend the Symposium to learn about the presentation process and students not currently involved in research are encouraged to attend the Symposium to learn about the broad range of undergraduate research activities that are taking place at ISU.

The first Symposium was held in April 2007. The 39 students who presented research and their mentors collectively represented all of ISU's Colleges: Agriculture and Life Sciences, Business, Design, Engineering, Human Sciences, Liberal Arts and Sciences, Veterinary Medicine, and the Graduate College. The event has grown to regularly include more than 100 students presenting on topics that span the broad range of disciplines studied at ISU.

Chemical and Biological Engineering

Statistics have shown approximately 20% of deaths every year in the US are as a result of cancer. Most of these deaths aren’t caused by the primary tumor, but the migration of cancer cells and their subsequent tumor growth. It has been found that many cells migrate directional using different cues. The directional cues have been identified as electrical gradients, stiffness gradients, chemical gradients, or fiber alignment. Cell migration along aligned fibers is called contact guidance. While these cues have been identified to cause directional migration, there has not been an in-depth study on how cells are responding to these cues.

Our purpose was to characterize the effect of matrix stiffness on contact guidance migration. Collagen fibers were used as the contact guidance platform, since collagen makes up the fibrous region of the extracellular matrix. Mica has been found by our lab to be a good platform to grow aligned collagen fibers due to its ionic surface chemistry and ordered structure. However, mica is stiff and not tunable. In order to characterize cell alignment, a transplantation method was also developed to transfer fibers to polymer surfaces with tunable stiffness like polyacrylamide and polydimethylsiloxane. Alignment and elongation of the cells were characterized through fixing and staining the cells. Long time-lapse migration was examined and speed and persistence of the cells along the fiber cue was calculated. From preliminary results, we could confirm the effectiveness of our transfer method from mica to functionalized polymer surfaces. In addition, stiffer substrates seem to lead to better elongation and alignment with the matrix. This leads us to believe that stiffer extracellular matrices could be worse for cancer cell metastasis.