Biomedical Engineering and Bioengineering Commons^™

Environment And Response Of 3d-Encapsulated Mesenchymal Stem Cells To Mechanical Loading, Augustus Greenwood

McKelvey School of Engineering Theses & Dissertations

This thesis explores the micromechanical environment induced when cyclically compressing hydrogels via finite element modeling and experimentally on the impact of loading on mesenchymal stem cells (MSCs) when encapsulated withing 3D hydrogel matrices. Degenerative joint diseases, characterized by cartilage degradation, present significant challenges due to cartilage's limited self-repair capacity. Innovative approaches, including stem cell-based therapies and engineered biomaterials, have emerged as promising strategies for cartilage repair and regeneration. This work specifically investigates the calibration of a bioreactor, the uniformity of load response across the hydrogel constructs via finite element modeling (FEM), and the stress response of MSCs subjected to various …

Low Impedance, Durable, Self-Adhesive Hydrogel Epidermal Electrodes For Electrophysiology Recording, Naiyan Wu

McKelvey School of Engineering Theses & Dissertations

Traditional electrodes used for electrophysiology recording, characterized by their hard, dry, and inanimate nature, are fundamentally mismatched with the soft, moist, and bioactive characteristics of biological tissues, leading to suboptimal skin-electrode interfaces. Hydrogel materials, mirroring the high water content and biocompatibility of biological tissues, emerge as promising candidates for epidermal electronic materials due to their adjustable physicochemical properties. However, challenges such as inadequate electrical conductivity, elevated skin impedance, unreliable adhesion in moist conditions, and performance decline from dehydration have significantly restricted the efficacy and applicability of hydrogel-based electrodes. In this thesis, we report a high-performance hydrogel epidermal electrode patch for …

Plasmonically-Enhanced Dna-Rna Hybrid-Based Bioassay For Amplification-Free Quantification Of Sars-Cov-2, Yuxiong Liu

McKelvey School of Engineering Theses & Dissertations

Corona Virus Disease 2019 (COIVD-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly infectious respiratory illness. Within just a few months, it spread around the whole world and became a global pandemic. Real-time reverse-transcription polymerase chain reaction (RT-PCR) works as a gold standard method diagnosing COVID-19 with high sensitivity and specificity. But due to the programs of RT-PCR, it usually takes more than 24 hours to get the results while specialized devices are also required. False-negative results can happen as well using RT-PCR which increase the risk of spreading coronavirus. To promote quicker detection of COVID-19, …

Injectable Ct/Mri Contrast Agent For Gastrointestinal Tumor Tracking, Luna Zhang

McKelvey School of Engineering Theses & Dissertations

Gastrointestinal cancers remain to be of the most common and deadly cancers worldwide. Early detection and treatments are crucial for reducing mortality and improving patient outcome. Radiation therapy is a non-invasive localized tumor treatment method, and utilizes radiation to kill the cancerous cells and shrink tumors at specific sites. Precise localization at the target tumor site is therefore important before radiation therapy, especially for gastrointestinal tumor sites located in the moving bowel. Currently, invasive endoscopies along with ink tattoos are used for identifying tumor location, which often require sedation and bring much discomfort. Imaging tests, including CT and MRI, play …

Liposomal Delivery Of Remdesivir For Localized And Targeted Treatment Of Covid-19, Anupama Melam

McKelvey School of Engineering Theses & Dissertations

Liposomal delivery of Remdesivir for localized and targeted treatment of COVID-19

COVID-19 is a serious, and in many cases lethal, disease that is caused by infection of the upper respiratory tract by the novel betacoronavirus, SARS-Cov-2 virus. This disease has a very high mortality rate and has affected the world in a global pandemic. SARS-Cov-2 binds to the ACE2 receptor via the receptor-binding domain (RBD) in the S protein. After this, the virus fuses with the cell membrane by the formation of a six-helix bundle. Thus, the S protein plays a major role in ensuring that the virus attaches to …

Ph-Sensitive Oxygen Release Microspheres To Enhance Cell Survival In Ischemic Condition, Zhongting Liu

McKelvey School of Engineering Theses & Dissertations

Ischemic diseases such as myocardial infarction, stroke and limb ischemia are severe cardiovascular diseases with high rate of death and millions of people suffered from these diseases. Under ischemic environment, cells die due to deficient supply of nutrient and oxygen. To regenerate ischemic tissues, stem cell therapy is a promising approach because stem cells can differentiate into cells necessary for the regeneration. However, stem cell therapy has limitations. For example, few cells can survive under harsh ischemic environment. To enhance stem cells survival, implantation of oxygen release microspheres to sustained supply cells with oxygen represents an effective strategy. Previously, our …

Activity Preservation Of Plasmonic Biosensors With A Metal-Organic Framework, Lu Wang

McKelvey School of Engineering Theses & Dissertations

Antibody-antigen recognition enables antibody-conjugated nanostructures to serve as plasmonic biosensors with tunable specificity. However due to the instability of antibodies, these biosensors are susceptible to changes in the environment such as heat and aridity, leading to constraints on the transportation and handling of these sensors. Here we establish a method using a metal-organic framework crystal to preserve biosensor activity under severe environmental conditions, including exposure to high temperatures, an organic solvent and a proteolytic agent. After zeolitic imidazolate framework-8 (ZIF-8) crystals formed for 12 hours on a biosensor of gold nanorods conjugated with a model antibody, rabbit IgG, 80% of …