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Current Students

Sudeep Sunthankar

Sudeep is a Park Scholar and a senior in Biomedical Engineering. His area of emphasis is biomechanics. He is doing research in a microfabrication lab at the University of North Carolina at Chapel Hill under the supervision of Dr. Nancy Allbritton and Dr. Wei Xu. His project is focused on creating an efficient protocol for the fabrication of microcup arrays. The overall goal of the research is to produce a mechanism by which individual cells or colonies may be separated from a population containing a wide variety of cells. Currently, a microcup technique has provided great promise. The functionality of the microcup is defined by its ability to capture desired cells without a requirement for walls along the interacting substrate. While current methodologies do exist, these procedures are often time intensive and expensive. The first step in the experimentation was the identification of a material which provided the necessary mechanical properties for the hot embossing technique. Hot embossing allows the photoresist slide to be imprinted with a particular design by heating the photoresist surface to a soft state at which point the mold material can emboss the desired pattern. Once the baking time and temperature of the embossing procedure had been optimized to produce viable arrays, the focus shifted to the alignment requirements. Mask alignment is a tedious and time intensive procedure which limits the efficiency of microcup fabrication. The second portion of the project deals with designing and implementing a new technique which would eliminate the need for aligning each individual slide with the corresponding mask and would thus streamline production.

John Yanik

John is a Park Scholar and a senior in Biomedical Engineering. His area of emphasis is biomechanics. He is conducting research at the University of North Carolina at Chapel Hill under the supervision of Dr. Richard Superfine. His research focuses on the use of electro-spinning to create a biomimetic,elastic substrate for bronchial epithelial cell culture. By growing lung cells on a stretchy, porous membrane under a cyclic loading pattern, researchers can better imitate within the lab the strain that these cells naturally undergo due to lung expansion and compression as the body breathes. This work also brings with it the added challenge of designing a method to mechanically stretch the growth channel in physiologically relevant ways as the cells develop under sterile conditions, over the course of several weeks, inside an incubator. The outcomes of such a project are vast, and could range from expanding our understanding of how cyclic loading patterns affect cell growth and differentiation, to a complex portrait of the mechanisms by which the development of an infection in the lung cells interacts with and alters the mechanical properties of the underlying extra-cellular matrix.

Daniel Cunningham

Daniel is in the University Honors Program and a senior in Biomedical Engineering. His area of emphasis is biomaterials. Daniel conducted his research at NC State University under the supervision of Dr. Elizabeth Loboa. His research focused on Human adipose-derived stem cells (hASC) that were seeded onto nylon scaffolding and subjected to pulsatile fluid flow-induced shear stress for 1 and 2-week durations at four hours per day in an osteogenic medium. A static control group was also simultaneously maintained. He found that hASC remained viable on the nylon winged-fiber scaffolding in the presence and absence of fluid shear stress (delivered using a Masterflex pulsatile fluid flow bioreactor). The cells adhered strongly enough to resist being swept away in 1 dyne/cm^2 shear stress. He observed upregulation in calcium accretion in the short term (1-week samples) indicating osteogenesis and downregulation in calcium accretion in the long term (2-week samples). The shear stress samples may have lost calcium in their matrix due to the action of the flowing liquid breaking down the calcium matrix while the static samples did not have to resist fluid flow, resulting in a greater deposition of the calcium matrix at the time that samples were taken. This study indicates that fluid shear stress along with chemical stimulation may be important for initiating differentiation of stem cells down an osteogenic pathway.

Kyle Cutler

Kyle is a College of Engineering Ambassador and a senior in Biomedical Engineering. His areas of emphasis are bioinstrumentation and biomechanics. Kyle conducted his research at NC State University under the supervision of Dr. Glenn Walker. Dr. Walker?s research laboratory focuses on microfluidics and the application of small scale devices to medical problems. The research project that Kyle worked on was called tumor-on-a-chip. The goal of the project was to create a microfluidic environment to simulate in vivo tumor conditions. The focus of the project was to recreate cyclical hypoxic conditions that are seen in solid tumor cells due to irregular blood flow and vasculature. The current literature suggests that this cyclical oxygen concentration has an effect on the ability of cancer cells to metastasize into other parts of the body. This project aimed at testing this current idea on the microscale level.
The specifics of the project that he worked on focused on finding a suitable validation process using fluorescent dyes to measure oxygen values seen in the microfluidic device. A suitable dye was found to measure the oxygen concentration on the chip and it has been validated against needle point oxygen sensors. Kyle was able to design and create multilayer microfluidic channels using soft photolithography. In addition, he was able to construct an experimental setup using multiple gas cylinders and control valves to create waveforms of oxygen concentrations that can interface with the microfluidic channels. The setup allows for cells to be put into the channels and for oxygen to flow over cells recreating the oxygen environment seen in the body. The next step in the project which Kyle will be working on this year focuses on implementation of the experimental setup and incorporating a microfluidic assay to measure the potential to metastasize.

Adam Willson

Adam is a senior in Biomedical Engineering. His area of emphasis is biomechanics. Kyle conducted his research at The University of North Carolina at Chapel Hill under the supervision of Dr. Sha Chang, Head of the Physics and Computing Divisions in the Radiation and Oncology Department located in the Cancer Hospital. The title of his project was "Statistical Modeling based Guidance for Radiotherapy Treatment Planning." The long term goal is to use prior information from radiotherapy treatments to evaluate the quality of a specific patients plan. There are many parameters that go into planning radiotherapy treatment, and the first step was to figure out a way to collect these parameters. Adam wrote a program to automatically collect these parameters from each specific patient. He and his team then conducted several statistical analyses on large sets of data. The project is still ongoing and they are hoping that they can produce some meaningful results.

Shelly Cochran

Shelly is a senior in Biomedical Engineering. Her area of emphasis is biomaterials. Shelly conducted her research at The University of North Carolina at Chapel Hill under the supervision of Dr. James E. Bear, Director of the UNC-Olympus Imaging Research Center at the Lineberger Comprehensive Cancer Center. Her research project focused on invadopodia and focal adhesions - structures in invasive cancer cells that promote cell motility and the degradation of the extracellular matrix (surrounding tissue). Focal adhesions are adhesive structures responsible for cell traction and some matrix degradation, while invadopodia are major sites of matrix degradation. She plated melanoma cells on gelatin, and using confocal, fluorescent, and live-cell microscopy to simultaneously capture the growth of focal adhesions, invadopodia, and the corresponding formation of the gelatin degradation across time. To quantify the results, a systematic approach was employed to collect, process, and analyze the data. The imaging techniques were also employed to capture the effects of various drug treatments on focal adhesions and invadopodia. Although focal adhesions and invadopodia differ in molecular architecture, they have many proteins in common which has led to the theory that the two compete for common molecular components. These research endeavors could contribute in determining if there is an optimal balance of focal adhesion and invadopodia dynamics that maximizes cell invasion. Knowing more about the relationship between invadopodia and focal adhesions would be beneficial in using the breakdown of these structures as anti-metastatic cancer therapy strategies.

John Miller

John is a Park Scholar and a junior in Biomedical Engineering. His area of emphasis is biomechanics. John conducted his research at NC State University under the supervision of Dr. Greg Sawicki. John worked on a gait analysis study that compared symmetric and asymmetric human locomotion. Because stroke patients typically experience partial paralysis or muscle weakness, they are forced to walk asymmetrically. As a result, it is important to study how their impaired walking influences energy and mechanical power output of the lower limb joints. His experimental setup simulated symmetric and asymmetric walking by fitting a locked boot onto the subject and asking them to walk with no ankles locked andone ankle locked. He found that impaired ankle pushoff occurred as a result of locking the ankle, and its mechanical power output was significantly reduced with the hip partially compensating. In addition, he also found that asymmetry affected both limbs, not just the impaired one. He hopes to expand on the study by adding more subjects and collecting metabolic energy costs in order toquantify how the loss of power affects the amount of energy required for stroke patientsto walk.