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Full-Text Articles in Biomedical Engineering and Bioengineering

Bioengineering Extracellular Matrix Scaffolds For Volumetric Muscle Loss, Kevin Roberts Aug 2019

Bioengineering Extracellular Matrix Scaffolds For Volumetric Muscle Loss, Kevin Roberts

Theses and Dissertations

Volumetric muscle loss overwhelms skeletal muscle’s ordinarily capable regenerative machinery, resulting in fibrosis and severe functional deficits which have defied clinical repair strategies. My work spans the design and preclinical evaluation of implants intended to drive the cell community of injured muscle toward a regenerative state, as well as the development of an understanding of the molecular responses of this cell community to biomaterial interventions. I demonstrate a new class of biomaterial by leveraging the productive capacity of sacrificial hollow fiber membrane cell culture; I show specifically that unique threads of whole extracellular matrix can be isolated by solvent ...


Investigation Of The Effect Of Age On Regenerative Outcomes Following Treatment Of Volumetric Muscle Loss Injuries, John Taehwan Kim Aug 2019

Investigation Of The Effect Of Age On Regenerative Outcomes Following Treatment Of Volumetric Muscle Loss Injuries, John Taehwan Kim

Theses and Dissertations

Volumetric muscle loss (VML) is a traumatic injury in skeletal muscle resulting in the bulk loss of more than 20% of the muscle’s volume. Included in the bulk loss of muscle is the skeletal muscle niche comprised of nerve bundles, vasculature, local progenitor cells, basal lamina, and muscle fibers, overwhelming innate repair mechanisms. The hallmark of VML injury is the excessive accumulation of non-contractile, fibrotic tissue and permanent functional deficits. Though predominant in the younger demographic, the elderly population is also captured within VML injuries. There are many factors that change with aging in skeletal muscle that may further ...


Generation Of A Ccl2 Knockout Using Crispr/Cas9 And Lipid Mediated Transfection In Ct-26 Murine Colon Carcinoma Cells, Emma Sullivan Aug 2019

Generation Of A Ccl2 Knockout Using Crispr/Cas9 And Lipid Mediated Transfection In Ct-26 Murine Colon Carcinoma Cells, Emma Sullivan

Biomedical Engineering Undergraduate Honors Theses

CCL2 is an inflammatory mediator that is released by tumor cells to activate and direct immune cell species, especially macrophages, to inflammatory sites within the body. The goal of this project was to successfully generate knockout the CCL2 ligand gene using a CRISPR/Cas9 complex delivered via lipid mediated transfection. The sgRNA and Cas9 mRNA were introduced into the cells via lipid-mediated transfection. The cells were incubated for 4 days, before being analyzed using PCR and gel electrophoresis. We expected to see one band on the first gel and two bands on the second gel. Two bands appeared on the ...


Diffuse Reflectance Spectroscopy To Quantify In Vivo Tissue Optical Properties: Applications In Human Epithelium And Subcutaneous Murine Colon Cancer, Gage Joseph Greening May 2019

Diffuse Reflectance Spectroscopy To Quantify In Vivo Tissue Optical Properties: Applications In Human Epithelium And Subcutaneous Murine Colon Cancer, Gage Joseph Greening

Theses and Dissertations

Colorectal cancer is the 4th most common and 2nd deadliest cancer. Problems exist with predicting which patients will respond best to certain therapy regimens. Diffuse reflectance spectroscopy has been suggested as a candidate to optically monitor a patient’s early response to therapy and has been received favorably in experimentally managing other cancers such as breast and skin. In this dissertation, two diffuse reflectance spectroscopy probes were designed: one with a combined high-resolution microendoscopy modality, and one that was optimized for acquiring data from subcutaneous murine tumors. For both probes, percent errors for estimating tissue optical properties (reduced scattering coefficient ...


Investigating Virus Clearance Via Ph Inactivation During Biomanufacturing, Wenbo Xu May 2019

Investigating Virus Clearance Via Ph Inactivation During Biomanufacturing, Wenbo Xu

Biomedical Engineering Undergraduate Honors Theses

In the processing of biopharmaceuticals, viral clearance and viral safety are important for the development of monoclonal antibodies. Murine xenotropic leukemia virus (XMuLV) is one of the retroviruses, recommended by Food and Drug Administration (FDA) as a model virus for viral clearance via inactivation from therapeutics derived from Chinese hamster ovary cells (CHO). A robust and effective method was investigated to clear or inactivate endogenous viruses by low pH inactivation. The effects of different conductivity and inactivated time on XMuLV clearance was determined. Acetate buffer was prepared with different conductivity, and 2% XMuLV was spiked into acetate buffer. XMuLV virus ...


Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee May 2018

Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee

Theses and Dissertations

Oxidative metabolism is required to produce adequate energy to sustain human life. A primary example of deteriorating oxidative capacity is seen in the cardiac musculature during chronic heart failure. This suggests that by improving oxidative potential, chronic heart disease could be mitigated and one approach to accomplish this may be through targeting the mt-mRNA translation system. Purpose: This investigation’s purpose was to characterize disruptions in mt-mRNA translation machinery in multiple forms of cardiomyopathy and to determine if mitochondrial mRNA translation initiation factor (mtIF2) is necessary to maintain oxidative capacity in cardiomyocytes. Methods Using a combination of animal and cell ...


Novel Methodology For Emboli Analog Production And In-Vitro Simulation Of Acute Ischemic Stroke, Anne Preut May 2018

Novel Methodology For Emboli Analog Production And In-Vitro Simulation Of Acute Ischemic Stroke, Anne Preut

Theses and Dissertations

Stroke is the leading cause of disability and a primary cause of mortality, resulting in an estimated $33 billion dollars spent on healthcare, rehabilitation and lost productivity in the United States each year. The most prevalent cause of stroke incidents are acute ischemic events, manifested as blood clots in the vasculature supplying the brain. Current gold standard treatments have improved since 2006 with the introduction of mechanical stent retrievers; however, several issues with the current treatments to acute ischemic stroke remain. Thrombolysis of the clot with a tissue plasminogen activator may lead to weakening the vessel wall and consequently, hemorrhaging ...


Structure And Property Of Polymers And Biopolymers From Molecular Dynamic Simulations, Xiaoquan Sun May 2018

Structure And Property Of Polymers And Biopolymers From Molecular Dynamic Simulations, Xiaoquan Sun

Theses and Dissertations

Natural and synthetic polymers and biopolymers have been studied for a variety of applications in food emulsion, biopharmaceutical purification, tissue engineering, and biosensor. The structure and property of polymers and biopolymers are critically important to determine their functions. Molecular dynamics (MD) simulations have a unique advantage to explore the structure and property of polymers and biopolymers from the molecular level. In the dissertation, MD simulations were conducted to study the mechanisms of various biological and chemical processes controlled by polymers and biopolymers based on real-world experimental results.

Seven heptapeptides have been screened from a peptide library in our earlier study ...


Effects Of Gsk101 Exposure On Astrocyte Mechanical Properties, Collagen Production, And Viability, Ethan Echols May 2018

Effects Of Gsk101 Exposure On Astrocyte Mechanical Properties, Collagen Production, And Viability, Ethan Echols

Biomedical Engineering Undergraduate Honors Theses

Transient receptor potential vanilloid 4 (TRPV4) is a cation channel protein which is thought to facilitate extracellular matrix (ECM) modification and glial scar formation following traumatic brain injury (TBI). Activation of TRPV4 has been shown to correlate with an increase in intracellular Ca2+ concentration. TRPV4 is subject to both chemical and mechanical activation. This study involved chemical activation of TRPV4 in cultured mouse astrocytes using GSK101, the primary agonist of TRPV4, and subsequent evaluation of mechanical and chemical changes to the ECM. Prior to GSK101 exposure, the cells were seeded into Matrigel Matrix, a gelatinous protein mixture intended to ...


Quantification Of Tumor-Associated Macrophages Following Immunomodulation Therapy In A Murine Allograft Model Of Colorectal Carcinoma, Caroline Spainhour May 2018

Quantification Of Tumor-Associated Macrophages Following Immunomodulation Therapy In A Murine Allograft Model Of Colorectal Carcinoma, Caroline Spainhour

Biomedical Engineering Undergraduate Honors Theses

Colorectal Carcinoma (CRC) is one of the deadliest cancers in the world, with 150,000 new cases annually in the United States. Traditional treatments include chemotherapy and invasive surgery; however, research has shown that only 25% of patients that undergo traditional treatment have a positive result. Immunotherapy is an emerging form of cancer treatment that utilizes the patients’immune system to fight cancer cells by targeting inflammation, which plays a large role in the proliferation and metastasis of cancer cells.

Tumor-associated macrophages (TAMs) are immune cells that affect the inflammatory microenvironment of tumors. TAMs are M1 in the early stages ...


Experimental And Model-Based Terahertz Imaging And Spectroscopy For Mice, Human, And Phantom Breast Cancer Tissues, Tyler Bowman Jan 2018

Experimental And Model-Based Terahertz Imaging And Spectroscopy For Mice, Human, And Phantom Breast Cancer Tissues, Tyler Bowman

Theses and Dissertations

The goal of this work is to investigate terahertz technology for assessing the surgical margins of breast tumors through electromagnetic modeling and terahertz experiments. The measurements were conducted using a pulsed terahertz system that provides time and frequency domain signals. Three types of breast tissues were investigated in this work. The first was formalin-fixed, paraffin-embedded tissues from human infiltrating ductal and lobular carcinomas. The second was human tumors excised within 24-hours of lumpectomy or mastectomy surgeries. The third was xenograft and transgenic mice breast cancer tumors grown in a controlled laboratory environment to achieve more data for statistical analysis.

Experimental ...


Effects Of Uniaxial Cyclic Strain On Endothelial Progenitor Cells, Maria Alejandra Zeballos Castro Dec 2017

Effects Of Uniaxial Cyclic Strain On Endothelial Progenitor Cells, Maria Alejandra Zeballos Castro

Biomedical Engineering Undergraduate Honors Theses

Despite the high prevalence of calcific aortic valve disease (CAVD), the underlying mechanisms of pathogenesis have not been found yet. Therefore, it is extremely important to study CAVD and understand how it develops. For this matter, we decided to study the potential of endothelial progenitor cells (EPCs) for use in tissue-engineered models of heart valves. EPCs were chosen as the cell source of interest for this study due to their high neovascularization potential and use in regenerative medicine and cardiovascular tissue engineering.

In this project, we aimed to engineer the microenvironment of cells that are involved in the formation of ...


Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le Aug 2017

Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le

Theses and Dissertations

To be used in health care, the safety and effectiveness of nanoparticles needs to be tested in a living organism. The objective of this project was to develop the chicken as a convenient animal model to examine tissue targeting of intravenously (i.v.)-injected iron oxide (IO) nanoparticles. In Experiment 1, different doses of IO-COOH were i.v. injected into chickens; blood was collected at 0, 5, 15, 30, and 60 minutes post-injection; liver, spleen, lung, and kidney were collected after the last blood collection. For Experiment 2, IO-COOH and IO-PEG were i.v. injected into chickens; blood and the ...


Detection Of Leukocytes Stained With Acridine Orange Using Unique Spectral Features Acquired From An Image-Based Spectrometer, Courtney J. Hunter May 2017

Detection Of Leukocytes Stained With Acridine Orange Using Unique Spectral Features Acquired From An Image-Based Spectrometer, Courtney J. Hunter

Biomedical Engineering Undergraduate Honors Theses

A leukocyte differential count can be used to diagnosis a myriad blood disorders, such as infections, allergies, and efficacy of disease treatments. In recent years, attention has been focused on developing point-of-care (POC) systems to provide this test in global health settings. Acridine orange (AO) is an amphipathic, vital dye that intercalates leukocyte nucleic acids and acidic vesicles. It has been utilized by POC systems to identify the three main leukocyte subtypes: granulocytes, monocytes, and lymphocytes. Subtypes of leukocytes can be characterized using a fluorescence microscope, where the AO has a 450 nm excitation wavelength and has two peak emission ...


Scaffold And Tissue Based Therapies To Improve Skeletal Muscle Regeneration After Volumetric Muscle Loss, Benjamin Kasukonis Dec 2016

Scaffold And Tissue Based Therapies To Improve Skeletal Muscle Regeneration After Volumetric Muscle Loss, Benjamin Kasukonis

Theses and Dissertations

Volumetric muscle loss (VML) is an injury to skeletal muscle characterized by a loss of more than 20% of a muscles volume. The combination of the bulk loss of tissue, transection and separation of myofibers proximal and distal to the injury, loss of innervation and blood supply, and the depletion of muscle progenitor cells results in permanent fibrosis and functional deficits due to loss of contractile tissue. Scaffolds, cells, and engineered constructs have been explored as potential therapeutic interventions to induce myogenesis at the site of a VML injury in animal models, in addition to limited clinical trials. This dissertation ...


Exploring Biomarkers For Point Of Care Bladder Cancer Detection, Cassandra M. Walker May 2016

Exploring Biomarkers For Point Of Care Bladder Cancer Detection, Cassandra M. Walker

Biomedical Engineering Undergraduate Honors Theses

Bladder cancer is the 5th most common non-cutaneous human cancer in the United States. While effective methods of detecting bladder cancer are currently practiced, they are often expensive and invasive. There is a need for a noninvasive detection method that can be used in areas with few medical resources. Cell free DNA in urine is normally present only in very low concentrations. Abnormally high levels of cell free DNA in urine could be indicative of disease. This study tests the hypothesis that DNA present in urine can be used as a biomarker for bladder cancer before hematuria is seen in ...


Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds, Jakob Hockman May 2016

Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds, Jakob Hockman

Biomedical Engineering Undergraduate Honors Theses

Metallic single-walled carbon nanotubes (m-SWNTs) were separated from pristine SWNTs using affinity chromatography for use in electrically conductive tissue engineering scaffolds. Approximately one third of SWNTs have metallic properties. Separations were achieved using a protocol modified from Liu & coworkers (2011) in order to improve the method for cell culture environments. Samples enriched in m-SWNTs were isolated and characterized. However, challenges still remain for the complete separation of m-SWNTs from their semiconducting counterpart (s-SWNTs) using this protocol. Approaches to improve separation and reduce the difficulties associated with processing the nanotubes were suggested. One of the ultimate destinations of these nanotubes would ...


Modulation Of Valve Interstitial Cell Function Through Cell Shape And Phenotype, Atefeh Razavi Dec 2015

Modulation Of Valve Interstitial Cell Function Through Cell Shape And Phenotype, Atefeh Razavi

Theses and Dissertations

The aortic valve is a highly dynamic structure responding to actively to the chemical, mechanical and physical cues of the valve microenvironment. Valve interstitial cells are dispersed throughout the valve tissue and play an important role in maintaining the integrity and optimum function of the valve. They are a heterogeneous population composed of various phenotype. These phenotypes have specific functions characteristic of valve physiological and pathological conditions. The effect of mechanical loading and chemical modulators on the behavior of the valve interstitial cells have largely been studied. However the role of valve interstitial cell shape as an intrinsic physical cue ...


Characterization Of Human Muscle Extracellular Matrix, Lauren Klaire Wilson Jul 2015

Characterization Of Human Muscle Extracellular Matrix, Lauren Klaire Wilson

Theses and Dissertations

The performance of extracellular matrix (ECM) biological scaffolds for the treatment of volumetric muscle loss (VML) has shown promising results with regenerating native muscle in animal models and human patients. However, the limitations of these scaffolds include non-specific characteristics based on the original parameters of the muscle that is lost and this is why our group chose to characterize human skeletal ECM. By understanding the characteristics of the native human skeletal ECM, more desired queues for the biological scaffolds being used to treat VML can be provided. Upper limb and lower limb skeletal muscles were commercially obtained, decellularized using common ...


Capillary Electrophoresis For Analysis Of Aβ1-42 Adsorption And Photo-Crosslinking, Jennifer Lynn Kurtz Jul 2015

Capillary Electrophoresis For Analysis Of Aβ1-42 Adsorption And Photo-Crosslinking, Jennifer Lynn Kurtz

Theses and Dissertations

The accumulation of amyloid-beta (Aβ) oligomers is believed to be the driving force behind Alzheimer’s disease (AD) pathogenesis. Due to the metastable nature of Aβ oligomers, the knowledge of Aβ aggregation and accumulation is not well understood. Here, we use capillary electrophoresis (CE) and photo-induced crosslinking of unmodified proteins (PICUP) to learn about the aggregation of Aβ.

First, we explore the effect of capillary coating on Aβ1-42 protein loss using CE. The dynamic coatings tested were PHEA and 50 kDa, 2000 kDa, 5000 kDa, and 8000 kDa PEO. The covalent coating tested was PVA. The results indicated that 2000 ...


Development And Characterization Of An Autologous Whole Cell Breast Cancer Vaccine, Samantha Leigh Kurtz Dec 2014

Development And Characterization Of An Autologous Whole Cell Breast Cancer Vaccine, Samantha Leigh Kurtz

Theses and Dissertations

Approximately 40,000 women will die from breast cancer in the United States in 2014. About 90% of these deaths will be due to metastases, rather than the primary tumor and majority of metastases are due to the recurrence and progression of non-metastatic disease. Current adjuvant treatments, such as chemotherapy and radiation, have severe side effects and may result in overtreatment and drug resistance.

Since greater than 90% of patients are diagnosed between stages I-III and have minimal residual disease after treatment, there is an opportunity to treat patients with an autologous breast cancer vaccine. Autologous vaccines under development have ...


Construction Of 3d Biomimetic Tissue Niches For Directing Pancreatic Lineage Differentiation Of Human Embryonic Stem Cells, Weiwei Wang Aug 2014

Construction Of 3d Biomimetic Tissue Niches For Directing Pancreatic Lineage Differentiation Of Human Embryonic Stem Cells, Weiwei Wang

Theses and Dissertations

The potential of human embryonic stem cells (hESCs) to differentiate into insulin producing beta cells offers great hope for cell-based therapy for diabetes treatment. However, in vitro pancreatic differentiation of hESCs remains challenging. In the past decade, most protocols for differentiating pancreatic cells have been focused on the use of signaling molecule cocktails on 2D substrates. Studies on embryonic development biology strongly suggest that extracellular matrix (ECM) plays a critical role on hESCs behavior. In this work, we first established a 3D collagen scaffold culture system for hESCs differentiating into definitive endoderm (DE), which is the first and most important ...


A Novel Cell Based Assay For Mmp Inhibitor Screening, Pantrika Krisanarungson Aug 2014

A Novel Cell Based Assay For Mmp Inhibitor Screening, Pantrika Krisanarungson

Theses and Dissertations

Up to date, a plethora of protein based materials are used as implants to stimulate tissue regeneration or fillers to alleviate tissue or organ impairment. This includes glottal insufficiency, urinary bladder incontinence and especially in cosmetic industrial to improve facial contour. Once in vivo, protein-based materials are decomposed by cell secreted matrix metalloproteinases (MMP) and lose their volume within months. By introducing MMP inhibitor (MMPI), the extent of material degradation over time may be reduced. In this dissertation, the development of cell-based assay capable of identifying MMPI candidates for protein-based implant lifetime prolongation is described. To visualize the degradation, DQ-gelatin ...


Improvements In Microdialysis Sampling Extraction Efficiency Using Recycled Flow, Justin Cole Deaton May 2013

Improvements In Microdialysis Sampling Extraction Efficiency Using Recycled Flow, Justin Cole Deaton

Theses and Dissertations

Incomplete recovery during microdialysis sampling is hindering important research in neurology, proteomics, and immunology. Although the current generalized solution, decreasing volumetric flow rates (Q), has been and will remain to be a useful strategy it has reached it's a physical limitation due to evaporation at the collection site. Consequently, many important signaling molecules, such as signaling proteins, remain difficult to study. It is more fundamental to consider relative recovery as a function of the interaction time between the perfusate and the environment surrounding the probe.

In this work an increase in relative recovery was predicted by a mathematical model ...


Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas May 2012

Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas

Theses and Dissertations

Stem cell and tissue engineering offer us with a unique opportunity to research and develop new therapies for treating various diseases that are otherwise incurable using traditional medicines. However, development of these new therapies replies upon the establishment of in vitro cell culture and differentiation systems that mimic in vivo microenvironments required for cell-cell and cell-ECM interaction. The development of these cell culture systems depends upon the identification of appropriate biomaterials and cell sources. Biomaterials should be carefully selected and fabricated into scaffolds for supporting cell growth and differentiation. In this study, we explored the fabrication of 3D electrospun nanofiber ...


Development Of A Microfluidic Device Coupled To Microdialysis Sampling For The Pre-Concentration Of Cytokines, Randy Francisco Espinal Cabrera May 2012

Development Of A Microfluidic Device Coupled To Microdialysis Sampling For The Pre-Concentration Of Cytokines, Randy Francisco Espinal Cabrera

Theses and Dissertations

A proof-of-concept microfluidic device combined with heparin-immobilized magnetic beads was created to concentrate cytokine proteins collected from microdialysis samples. Cytokines are known to be related to several diseases such as cancer, and Parkinson's diseases, so to be able to develop more effective diseases treatments their interactions have to be well understood. Amine-functionalized polystyrene and carboxyl-functionalized magnetic microspheres of ~6.0 ìm in diameter were used to immobilize heparin. The amount of heparin immobilized on polystyrene beads was 5.82 x 10-8 ± 0.36 x 10-8 M per 1.0 x 106 beads and for magnetic beads was 0.64 ...