Biomedical Engineering and Bioengineering Commons^™

Brain-Computer Interfaces Using Electrocorticography And Surface Stimulation, Jesse Wheeler

McKelvey School of Engineering Graduate Student Theses & Dissertations

The brain connects to, modulates, and receives information from every organ in the body. As such, brain-computer interfaces (BCIs) have vast potential for diagnostics, medical therapies, and even augmentation or enhancement of normal functions. BCIs provide a means to explore the furthest corners of what it means to think, to feel, and to act—to experience the world and to be who you are. This work focuses on the development of a chronic bi-directional BCI for sensorimotor restoration through the use of separable frequency bands for recording motor intent and providing sensory feedback via electrocortical stimulation. Epidural cortical surface electrodes are …

Radiological Pathological Correlations In Chronic Traumatic Encephalopathy, Mihika Gangolli

McKelvey School of Engineering Graduate Student Theses & Dissertations

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease that has been increasingly linked to traumatic brain injury. The neuropathology that distinguishes CTE from other tauopathies includes hyperphosphorylated tau (pTau) tangles and tau positive astrocytes irregularly distributed in cortical sulcal depths and clustered around perivascular foci. These features are clearly identified using immunohistochemistry, but are undetectable to current clinical imaging methods. Diffusion imaging has been proposed as a noninvasive method to detect the pathognomonic lesion of CTE in vivo because of its high sensitivity to microstructural alterations in tissue structure. While several diffusion imaging approaches, ranging from diffusion tensor imaging …

Development And Evaluation Of Biocompatible Engineered Nanoparticles For Use In Ophthalmology, Bedia Begum Karakocak

McKelvey School of Engineering Graduate Student Theses & Dissertations

The synthesis and design of biocompatible nanoparticles for targeted drug delivery and bioimaging requires knowledge of both their potential toxicity and their transport. For both practical and ethical reasons, evaluating exposure via cell studies is a logical precursor to in vivo tests. As a step towards clinical trials, this work extensively investigated the toxicity of gold nanoparticles (Au NPs) and carbon dot (CD) nanoparticles as a prelude to their in vivo application, focusing specifically on ocular cells. As a further step, it also evaluated their whole-body transport in mice. The research pursued two approaches in assessing the toxicity of engineered …

Hemodynamic Effects On Embryonic Arterial Growth And Matrix Remodeling, Maria Gabriela Espinosa

McKelvey School of Engineering Graduate Student Theses & Dissertations

Hemodynamic forces drive cardiovascular morphogenesis and remodeling in the developing embryo. Changes to the embryonic hemodynamic environment have been shown to induce a variety of congenital heart defects, but little attention has been given to vasculature-specific defects. Although vascular development has been widely studied in the context of genetics and molecular biology, this work investigates the impact of hemodynamic forces on arterial development and mechanics.

The dorsal aorta (DA) is the first intraembryonic vessel to form. Its passive mechanical properties are determined by the deposition of extracellular matrix (ECM) proteins, a hallmark of arterial maturation. We hypothesized that hemodynamic changes …

Forward Electrophysiological Modeling And Inverse Problem For Uterine Contractions During Pregnancy, Mengxue Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Uterine contractile dysfunction during pregnancy is a significant healthcare challenge that imposes heavy medical and financial burdens on both human beings and society. In the U.S., about 12% of babies are born prematurely each year, which is a leading cause of neonatal mortality and increases the possibility of having subsequent health problems. Post-term birth, in which a baby is born after 42 weeks of gestation, can cause risks for both the newborn and the mother. Currently, there is a limited understanding of how the uterus transitions from quiescence to excitation, which hampers our ability to detect labor and treat major …

In Vivo Vascular Imaging With Photoacoustic Microscopy, Hsun-Chia Hsu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photoacoustic (PA) tomography (PAT) has received extensive attention in the last decade for its capability to provide label-free structural and functional imaging in biological tissue with highly scalable spatial resolution and penetration depth. Compared to modern optical modalities, PAT offers speckle-free images and is more sensitive to optical absorption contrast (with 100% relative sensitivity). By implementing different regimes of optical wavelength, PAT can be used to image diverse light-absorbing biomolecules. For example, hemoglobin is of particular interest in the visible wavelength regime owing to its dominant absorption, and lipids and water are more commonly studied in the near-infrared regime.

In …

Multi-Beam Scan Analysis With A Clinical Linac For High Resolution Cherenkov-Excited Molecular Luminescence Imaging In Tissue., Mengyu Jeremy Jia, Peter Bruza, Lesley A. Jarvis, David J. Gladstone, Brian W. Pogue

Dartmouth Scholarship

Cherenkov-excited luminescence scanned imaging (CELSI) is achieved with external beam radiotherapy to map out molecular luminescence intensity or lifetime in tissue. Just as in fluorescence microscopy, the choice of excitation geometry can affect the imaging time, spatial resolution and contrast recovered. In this study, the use of spatially patterned illumination was systematically studied comparing scan shapes, starting with line scan and block patterns and increasing from single beams to multiple parallel beams and then to clinically used treatment plans for radiation therapy. The image recovery was improved by a spatial-temporal modulation-demodulation method, which used the ability to capture simultaneous images …

Efficacy Of Eluted Antibiotics In 3d Printed Orthopaedic Implants, Mohammed Mehdi Benmassaoud

Theses and Dissertations

Costs associated with musculoskeletal diseases in the United States account for 5.7 % of the Gross Domestic Product (GDP) [1]. As such, there is a need to pursue new ideas in orthopaedic implants that can decrease cost and improve patient care. In the recent years, 3D printing using Fused Deposition Modeling (FDM) or Stereolithography (SLA) has opened several exciting possibilities to create orthopaedic implants. Such implants can be engineered to release antibiotics in a controlled manner either by infusing the drug into the material during manufacturing or by using built-in design features such as micro-channels and reservoirs [2]. The use …

Bacteria Movement Near Surfaces, Shulin Wang, Adib Ahmadzadegan, Arezoo Ardekani

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding the behaviors of bacteria near surfaces is crucial in many biological and ecological applications. This knowledge can be used to hinder undesired biofilm formation on medical instruments and wounds. On top of that, it could also provide further insights in biodegradation of dispersed oil. In this work, the behavior of Escherichia Coli near a surface was experimentally studied. We utilized an inverted microscope in the phase filed illumination mode and processed acquired images to track the motions of bacteria near surfaces with high accuracy and repeatability. Distribution of the cells when they reached a steady state shows that the …

Thin Film Cocaine Sensors, Datta Sheregar, Vick Hung, Jenna Walker, Orlando Hoilett, Jacqueline Linnes, Robert Nawrocki

The Summer Undergraduate Research Fellowship (SURF) Symposium

Over 7 million Americans suffer from a drug use disorder and up to 60% of individuals treated for addiction will ultimately relapse. We are developing ultra-thin film electrodes on a wearable substrate for a sensor that can detect minute amounts of cocaine in sweat droplets secreted from the skin. This will enable wearable drug monitoring for personalized rehabilitation treatment plans and improve long-term addiction recovery rates. The current research focuses on developing a thin-film sensor that can be applied directly to the skin. First a layer of PVP (poly4-vinylphenol) was prepared and then spun coated onto a piece of glass. …

Characterization And Quantification Of Fibrin Gel Mechanics With Fibroblast Invasion, Nicklaus Iavagnilio, Sarah Calve, Adrian Buganza-Tepole

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cutaneous wounds undergo an intricate healing process stimulated by a variety of local mechanical and biological stimuli that lead to patterns of growth and remodeling. Despite significant research in dermal wound healing, pathological scarring is still common particularly in wounds closed under mechanical stress, or large wounds left to heal by secondary intention. The purpose of this study is to utilize previously established wound healing models using fibrin gels and fibroblasts to better understand the functional relationships of the biological processes of normal compared to abnormal wound healing. Increases in uni-axial strain and transforming growth factor beta-1 concentration have been …

Design Modifications For A Small, Affordable Low Intensity Focused Ultrasound Device, Sui Shen, Kelsey C. Bayer, Pedro P. Irazoqui

The Summer Undergraduate Research Fellowship (SURF) Symposium

Depression is a prevalent and serious medical illness, and while there are antidepressant drugs to mitigate depressive symptoms, 10 - 30% of patients either do not respond or develop a tolerance to these medications. Literature supports that there is an interrelation between the inflammatory response and treatment-resistant depression. A promising method to tackle depressive symptoms is to block the inflammatory signaling pathway with vagus nerve stimulation (VNS), reducing pro-inflammatory cytokine levels. Although electrical VNS devices exist, they are invasive, expensive, and have side effects including voice alteration, dyspnea, and cough. Low intensity focused ultrasound (LIFU) is a promising method that …

Rapid Sample Processing Of Foodborne Pathogens Using Cross-Flow Microfiltration, Casey Bomrad, Michael R. Ladisch, Linda Liu, Jessica Lynn Zuponcic, Eduardo Ximenes

The Summer Undergraduate Research Fellowship (SURF) Symposium

Foodborne illnesses are a prominent issue, causing 48 million illnesses annually. The Escherichia coli O157:H7 outbreak in romaine lettuce is a recent example. The source of the pathogen was contaminated irrigation water. The most common methods for detecting foodborne pathogens involve cultivation and enrichment of food samples. The enrichment steps are time-consuming, taking 24 to 72 hours to complete. Our study aims to accelerate irrigation water sample preparation for pathogenic microorganism fast detection through cross-flow microfiltration. This is accomplished by a device called a continuous cell concentration and recovery device (C3D). The C3D uses cross-flow microfiltration in a hollow fiber …

Developing Strategies To Toughen Bio-Inspired Adhesives, Narelli P. Narciso, Samuel Lee Huntington, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Mussels and other marine creatures adhere very well in underwater environments, having the ability to withstand the force of the sea. These animals have inspired synthetic biomimetic adhesives for wet systems, presenting potential for biomedical applications. However, most current commercial adhesives tend to be brittle, not resisting repetitive movements. This study assesses toughening strategies to improve the mussel-inspired adhesives’ ductility while maintaining its strength. The strategies included altering the polymer’s chemical structure by changing the percentage of polyethylene glycol (PEG) in the molecule and by adding fillers, such as calcium carbonate, silica and nacre - a calcium carbonate compound found …

Cost-Effective Paper-Based Diagnostic Using Split Proteins To Detect Yeast Infections, Zachary R. Berglund, Kevin V. Solomon, Mohit S. Verma, Moiz Rasheed, Zachary Hartley, Kevin Fitzgerald, Kok Zhi Lee, Janice Chan, Julianne Dejoie, Makayla Schacht, Alex Zavala

The Summer Undergraduate Research Fellowship (SURF) Symposium

The common yeast infection, vulvovaginal candidiasis, affects three out of four women throughout their lifetime and can be spread to their child in the form of oral candidiasis (thrush). This disease is caused by the fungal pathogen Candida albicans, which is also a major cause of systemic candidiasis, a rarer but deadly disease with up to a 49% lethality rate. Current widely-used diagnostic methods include cell cultures, pH tests, and antibody detection, to assist effective treatment. Despite availability of various diagnostic methods, there is no inexpensive, rapid, and accurate way to detect C. albicans infection. This project aims to …

Improving Biomanufacturing Production With Novel Elp-Based Transcriptional Regulators, Juya Jeon, Logan R. Readnour, Kevin V. Solomon

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microbes can be used to produce valuable drugs, chemicals, and biofuels, but their potential has not been fully realized due to low production yields. To improve biomanufacturing processes and yield, we are developing novel, transcriptional regulators using biosynthesis technology in order to improve cellular health and overall production. Our regulator contains elastin-like polypeptides (ELPs), which make ideal sensors since they exhibit a sharp, inverse phase transition to indicators of cell health such as intracellular pH and ionic strength, and external stimuli such as temperature. We hypothesize that ELP can be fused to transcription factors to control expression of target genes. …

Fluidic Control With Wax Valves For Paper-Based Diagnostics, Emilie I. Newsham, Elizabeth A. Phillips, Katherine N. Clayton, Jacqueline C. Linnes

The Summer Undergraduate Research Fellowship (SURF) Symposium

Paper-fluidic devices are a common platform for point-of-care disease detection in under-resourced areas because of their low cost and minimal instrumentation requirements. Limited fluidic control in paper-fluidic devices has hindered the incorporation of multistep reactions that are necessary for more sensitive disease detection. One potential fluidic control mechanism is the incorporation of thermally actuated wax valves to separate assay stages. Such valving would expand the detection capabilities of these devices by permitting fluid obstruction for sustained reactions and facilitating controlled volume release within a fully-automated, self-contained device. Despite the potential to exploit wax valves for innovative paper-fluidic diagnostics, a thorough, …

Magnetically Actuated Cell Stretching Platform To Induce Phenotypic Changes In Metastatic Cells, Yong Gyun Cho, Hyunsu Park, Hyowon Lee, Sarah Libring

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although metastasis is responsible for about 90% of cancer deaths, only few in vitro models can be used to evaluate dynamic behaviors of metastatic cancer cells. Many studies have shown that mechanical stimuli can trigger various cellular responses such as gene and protein expression, which could lead to changes in cellular phenotype. Similarly, metastasized breast cancer cells in the lung tissue are constantly stretched by cyclic mechanical stress due to breathing, which alters cellular morphology and proliferation state. Such transitions can make the secondary tumors resistant to the chemotherapy used to effectively treat the primary tumors. In this work, we …

Neural Coding Of An Auditory Pitch Illusion, Maria Alejandra Barrera, Mark Sayles, Ravinderjit Singh

The Summer Undergraduate Research Fellowship (SURF) Symposium

Pitch is an important perceptual dimension in audition, supporting auditory object segregation, melody recognition and lexical distinction. Huggins’ pitch, for example, is a phenomenon evoked by two sources of broadband noise presented binaurally with an inter-aural phase shift over a narrow frequency band. Huggins’ pitch and other dichotic pitches have been studied extensively using perceptual experiments. Several models have been proposed to explain and predict the perception of pitch; however, no studies have tried to record in vivo neuron responses to Huggins’ pitch (HP) nor have tried to explain how the HP is coded by neurons. The existence of pitches …

Tissue Clearing As A Mechanism To Identify Changes In Fibronectin Structure During Breast Cancer Metastasis, Maryam Nuru, Kelsey Hopkins, Luis Solorio

The Summer Undergraduate Research Fellowship (SURF) Symposium

With metastasis accounting for approximately 90% of breast cancer deaths and an alarming number of over 300,000 new breast cancer cases to be diagnosed by the end of 2018, there is growing need to understand the process of breast cancer. Changes in the extracellular matrix (ECM) of the tumor microenvironment play an essential role in this deadly tumor progression. Specifically, the glycoprotein fibronectin (FN), has been identified to be up-regulated in patients with worse clinical outcomes. During tumor progression fibronectin undergoes conformational changes that aid in metastatic dissemination. In order to analyze the dynamic changes in FN expression and evaluate …