The Biomedical Engineering REU is designed to provide independent research experience for undergraduate students, broaden participant knowledge of opportunities in academia, industry and national laboratories, and introduce participants to interdisciplinary research in biomedical devices.
The goal of every medical practitioner is to improve quality of life for patients. Biomedical technology and devices are instrumental in achieving this. The primary focus in each summer research project is biomedical devices designed to enhance medical care through science and engineering, with emphasis in three areas: (1) devices for surgical intervention, (2) devices for diagnostics, and (3) devices for implantation.
All projects are designed to be completed during the 10 week program and are a part of a faculty mentor's current research. This allows the student to be involved in many aspects of research, including design, analysis, simulation, and implementation of a biomedical device.
Students are also extensively involved in lab activities, such as weekly lab meetings. Research results are presented during lab meetings throughout the summer and at the end-of-summer in the Summer Research Symposium poster session. Lab members, especially graduate students and postdoctoral associates, are active with summer program research.
Competitive stipend: $5,000
Double-occupancy room and meal plan
Travel expenses to and from Lincoln
Campus parking and/or bus pass
Full access to the Campus Recreation Center and campus library system
Measuring Transient Cerebral Blood Flow Changes from Sensory Stimuli Using Transcranial Doppler
The REU student will study transient blood flow changes in the brain in response to sensory stimuli. The student will perform a literature review in one specific area (e.g., visual or aural stimulation); design and carry out experiments measuring cerebral blood flow in the middle, posterior, and anterior cerebral arteries with ultrasound on human subjects to analyze the effect of different sensory stimuli; analyze data; and have an opportunity to contribute to publications.
Ultrasound is a safe, noninvasive method of measuring blood flow in the body, and Transcranial Doppler (TCD) is a special ultrasound mode that measures blood flow in cerebral arteries deep in the brain. TCD may be used as an inexpensive, portable method to measure brain response since neural activity is correlated with blood flow in the cerebrum. For example, a visual stimulus (such as a strobe light) can evoke a change in blood flow to the visual cortex. This can be seen by a relative decrease in the flow within the middle cerebral artery compared to the posterior cerebral artery. For clinical reporting, blood flow measurements are typically reduced to a pulsatile or resistive index. However, this clinical value is typically based on long-term data averaging (i.e., tens of seconds), and this averaging removes the valuable real-time aspect of ultrasound. This project will assess the use of a new data index based on systems theory (relaxation time).
The REU student working with Dr. Gu will be guided to perform a literature search, formulate research questions, compare the mechanical performance of a commercial prosthesis (Edwards Life sciences, LLC, Irvine, CA) with the native aortic valve, and then propose a new leaflet design. The efficacy of the design will be justified using a design matrix and then tested. The REU student will be expected to conduct benchtop testing and computer-aided design and analysis. It is expected that (s)he will learn and apply principles of fluid and solid mechanics to a biomedical device design.
An estimated 20,000 people die annually from valve-related diseases, including those too sick to withstand traditional open-heart surgery. Use of the stented heart valve, which can be implanted through thin tubes known as catheters rather than by invasive open-heart surgery, would enable more patients to receive a life-saving, minimally invasive valve replacement. Benchtop testing of various catheter-based interventional vascular devices have been conducted in Dr. Gu’s Vascular Mechanics Laboratory, and some of the major challenges associated with the new valve prosthesis include resecting the native aortic valve and positioning the new prosthesis. The goal of this project is to develop a new design of a percutaneous prosthesis by changing its leaflet geometry. The central hypothesis is that the leaflet geometry affects the performance of prosthetic valve.
Correlating Carbon Nanotube Sensor Signals to Nitric Oxide Levels to Determine the Importance of Reactive Nitrogen Species in Inflammatory Disease Progression
The REU student will focus on the development of a numerical model in which the fluorescence signal changes of the sensor will be correlated to quantifiable nitric oxide levels. This model will be initiated at the bench top but will progress to in vitro and in vivo studies. Through the development of detailed protocols, collection and analysis of data, and interpretation of results, the REU student will learn the importance of rigorous scientific techniques while being exposed to cutting-edge research and current medical issues.
Reactive oxygen and nitrogen species have been shown to be important factors in the progression of many diseases, but until recently there has been a lack in the ability of researchers to study nitric oxide within cells in real time. By wrapping carbon nanotubes with a specific DNA strand, a sensor for nitric oxide that can be used both in vitro and in vivo was created through a collaboration, which was spearheaded by Dr. Iverson, between a chemical engineering and toxicity lab at MIT. This project will utilize the real time sensor capabilities of the carbon nanotubes to examine disease progression and create a better understanding of the importance of reactive species during development of an inflammatory disease, specifically melanoma. The central hypothesis of this project is that the concentration of nitric oxide in and around melanoma cells will significantly vary from control samples, showing extreme fluctuations, and will prove to be an important factor in determining tumor progression. This project will investigate both the in vitro and in vivo alterations in nitric oxide levels.
The REU student will engineer polymer-based platforms to control cell adhesion. (S)he will create a library that will be utilized in combination with microfabrication technology to engineer patterned co-cultures of cancer cells and stromal cells, thus gaining research experience in models that can be used to investigate the molecular mechanisms of how physical contact of the tumor cells and stromal cells regulate tumor biology and progression.
Breast cancer is the second leading cause of cancer-related death in women in the U.S. Recently, the breast tumor microenvironment has been implicated in playing a major role in facilitating tumor growth, progression, and metastasis. The microenvironment is highly organized and complex, consisting of multiple cell types that include fibroblasts, mesenchymal stem cells, epithelial cells, blood vessels, and extracellular matrix proteins. While the precise mechanisms of interaction are not fully understood, research has shown that cell signaling between the cancer cells and surrounding stromal cells alters the stromal phenotype, which in turn promotes tumor progression and metastasis. Dr. Kidambi’s project focuses on engineering matrix based in an in vitro co-culture model of breast cancer cells and stromal cells to recreate the cell-cell interaction involved in cancer progression. The central hypothesis is that direct tumor cell-stromal cell contact is a key component of the tumor progression and drug resistance pathways. A fundamental understanding of these interactions will provide insight into how to counter the microenvironment’s tumor-promoting behavior and uncover possible novel therapeutic targets for cancer treatment.
Molecular Mechanosensors of Flow-induced Stem Cell Migration
The REU student will apply physiologically relevant fluid shear stresses to mesenchymal stem cells (MSCs) using a well-defined macro-flow chamber and measure MSC migration on and transmigration through the endothelial cell monolayer that mimics the vascular wall. The student will be further involved in determining molecular mechanisms by testing the hypothesis that cell-substrate interaction and cytoskeletal tension signaling cascades will mediate MSC mechanosensing of flow shear.
Migrating mesenchymal stem cells (MSCs) contribute to homeostasis and modulate the repair of damaged tissues in vivo. MSC migration-dependent regenerative medicine strategies such as cell therapies have, however, suffered from low efficiency in cell homing to the target tissue. While conventional, soluble factor-driven “static chemotaxis” experiments have revealed some aspects of MSC migration and homing, there is a huge knowledge barrier with regard to how mechanical environments such as fluid flow-induced shear stress affect MSC migration, thus limiting the efficacy of cell therapies. This study investigates MSC migration and transmigration under fluid flow-induced shear conditions that mimic in vivo flow conditions, with the expectation that knowledge gained from this study will contribute to the development of more efficient and effective cell therapies.
Robotic Technology for Next-Generation Minimally Invasive Surgery
The REU student participating in this project will perform computer-aided design and simulation and will assist in prototype fabrication, testing, and evaluation. It is expected that (s)he will learn and apply principles of robot kinematics and dynamics, biomaterials selection, and engineering design methodology, along with somewhat lighter coverage in anatomy/physiology and computer science.
In surgery, the primary challenge is to maximize access to the surgical site in terms of dexterity and vision while minimizing invasiveness. In the past decade, robotic surgical tools have emerged as a way to improve dexterity and vision in minimally invasive procedures. Dr. Nelson’s lab is developing new robotic technology to increase functionality in medical interventions while reducing invasiveness. The specific research question addressed in this project is to investigate the quantifiable functional benefits of new robotic technology for minimally invasive surgery. Specifically, the investigation will focus on a novel robotic surgical system incorporating modular multifunction tools with a compact, dexterous telepositioning system. The intended approach is to enhance surgeons’ ability to perform complex procedures quickly and accurately using advanced robotics, while adding tele-operation capabilities and allowing easy conversion between manual and robotic surgical approaches.
The objective of this project is to develop methods to generate growth plate architecture, in particular features of the columnar chondrocytes, by encapsulation within alginate fibers. Students will be challenged to develop a method to produce alginate fibers of controlled diameters that encapsulate chondrocytes and then assess the viability and gene expression patterns of these cells, as well as work on methods to bundle fibers together to mimic zones of native growth plate.
Growth plate damage and dysfunction resulting from disease or physical injury leads to growth defects that reduce the quality of life, can impact the function of other organs, and cause long-term health issues. Damaged cartilage shows little propensity to repair or regenerate in vivo and efforts in tissue engineering have produced cartilage that lacks the zonal organization and growth characteristics of native growth plate cartilage. The objective of this project is to develop methods to generate growth plate architecture, in particular features of the columnar chondrocytes, by encapsulation within alginate fibers. Students will be challenged to develop a method to produce alginate fibers of controlled diameters that encapsulate chondrocytes and then assess the viability and gene expression patterns of these cells, as well as work on methods to bundle fibers together to mimic zones of native growth plate.
Fabrication and Characterization of Janus Hydrogel
The REU student will be involved in refining the hypothesis based on literature review; designing, fabricating, and testing multi-layered microfluidics platforms; conducting microscopy imaging of chondrocytes in the device; and analyzing data to test the hypothesis.
As the precursor of bone, cartilage consists of chondrocyte cells and collagen-based extracellular matrix (ECM). The mechanical stability and properties of cartilage result from the structure and composition of the ECM which develops in response to mechanical stimuli. Although it is unknown how mechanical forces direct ECM structure, the answer appears to involve differential chondrocyte organization in the cartilage because the chondrocytes generate ECM, and the mechanical environment of the cartilage appears crucial in maintaining the fidelity of the column forming process of the chondrocytes. The central hypothesis is that mechanical forces acting through cell-to-cell junctions promote specific alignment of chondrocytes. To test this hypothesis, Dr. Ryu’s lab is developing a microfluidics platform (in collaboration with Dr. Andrew Dudley of UNMC) to simultaneously apply controlled growth factor and compressive force to chondrocytes embedded in hydrogel matrix of tunable stiffness. The goal is to better understand how combined stimuli affect rotation of daughter chondrocytes after cell division, and this study will advance tissue engineering for cartilage.
Disappearable Cyber Physical System Sensors and Actuators
The REU student will review the latest literature on the topic and design, build, carry out, and analyze benchtop and live-animal experiments to test hypotheses regarding stabilization and localization of mesoscale swallowable robotic capsules.
The goal of this project is to enable a new generation of wearable sensors and actuators that can disappear within the natural orifices of the human body, thus enabling invisible, unobtrusive, long-term physiological monitoring to address the problem of infrequent, clinic-based measurements. This project focuses on using the gastrointestinal (GI) tract as a location for a long-term biosensing and control application. The GI tract’s large volume and surface area, proximity to vital organs and systems, and status as natural pathway in and out of the body makes it an ideal location for miniature biosensing systems. Though GI mechatronic platforms have advanced over the past decade, work is hampered by the fundamental challenge that swallowed items leave the body within 24 hours. The research objectives are to solve the problems of simple, non-invasive delivery of sensors and actuators to the GI tract; long-term persistence of sensors and actuators within the GI tract; and long-term supply of power to sensors and actuators within the GI tract. This work is expected to enable long-term hosting of Cyber Physical System CPS components within the GI tract; support the advancement of untethered, GI microsurgical platforms presently under development by multiple research groups; and may lead to a new field of study in disappearable physiological sensing and computing.