Biomedical Engineering and Bioengineering Commons^™

The Design And Validation Of A Computational Model Of The Human Wrist Joint, Afsarul Mir

Theses and Dissertations

Advancements in computational capabilities have allowed researchers to turn towards modeling as an efficient tool to replicate and predict outcomes of complex systems. Computational models of the musculoskeletal system have gone through various iterations with early versions employing dramatic simplifications. In this work, a three-dimensional computational model of the wrist joint was developed. It accurately recreated the skeletal structures of the hand and wrist and represented the constraints imposed by soft tissue structures like ligaments, tendons, and other surrounding tissues. It was developed to function as a tool to investigate the biomechanical contributions of structures and the kinematic response of …

Conserved Extracellular Cysteines Differentially Regulate The Potentiation Produced By Zn2+ In Rat P2x4 Receptors, Chao-Ying Li, Ke-Ming Xiong, Yu-Xiang Wu, Yu-Wei Liu, Lin Chen, Randall B. Stewart, Robert W. Peoples, Chu-Li Yi

Biomedical Sciences Faculty Research and Publications

One feature of the amino acid sequence of P2X receptors identified from mammalian species, Xenopus laevis and zebrafish is the conservation of ten cysteines in the extracellular loop. Little information is available about the role of these conserved ectodomain cysteines in the function of P2X receptors. Here, we investigated the possibility that ten conserved cysteine residues in the extracellular loop of the rat P2X4 receptor may regulate zinc potentiation of the receptor using a series of individual cysteine to alanine point mutations and functional characterization of recombinant receptors expressed in Xenopus oocytes. For the C116A, C132A, C159A, C165A, C217A and …

Tissue Engineering Composite Biomimetic Gelatin Sponges For Bone Regeneration, Isaac Rodriguez

Theses and Dissertations

The field of tissue engineering aims to develop viable substitutes with the ability to repair and regenerate the functions of damaged tissue. Common practices to supplement bone regeneration in larger defects include bone graft biomaterials such as autografts, allografts, xenografts, and synthetic biomaterials. Autologous bone grafting is the current gold-standard procedure used to replace missing or damaged bone. However, these grafts have disadvantages such as donor site morbidity, limited availability, and the need for a secondary surgery. The focus of this study is to tissue engineer a lyophilized gelatin composite sponge composed of hydroxyapatite (HA), chitin whiskers (CW), and preparations …

Multilayer Bioactive Glass/Zirconium Titanate Thin Films In Bone Tissue Engineering And Regenerative Dentistry, Masoud Mozafari, Erfan Salahinejad, Vahid Shabafrooz, Mostafa Yazdimamaghani, Daryoosh Vashaee, Lobat Tayebi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class …

Improving Bioactivity And The Anti-Bacterial Properties Of Two-Solution Bone Cement Containing Cross-Linked Polymethylmethacrylate (Pmma) Nanospheres (Η-Tsbc), Shailly Jariwala

Biomedical and Chemical Engineering - Dissertations

The high viscosity standard two-solution bone cements (STSBC) developed in our laboratory exhibits several advantages over other commercial powder-liquid cement formulations. However, the high monomer concentration, viscosity, and exothermal temperature are considered a major limitation to the use of this material. Modified two-solution cements containing cross-linked polymethylmethacrylate (PMMA) nanospheres (η-TSBC), as part of the polymer phase, were fabricated as the first step for optimization of cement viscosity for application of the material in the treatment of vertebral compression fractures using vertebroplasty (VP) and kyphoplasty (KP). The η-TSBC exhibited reduced viscosity, lower polymerization exotherm, and residual monomer in comparison to STSBC. …

Section Abstracts: Biomedical And General Engineering

Virginia Journal of Science

Abstracts of the Biomedical and General Engineering Section for the 91st Annual Virginia Journal of Science Meeting, May 2013

In Vivo Efficacy Of Chitosan/Interleukin-12 In Controlling Lung Metastasis In 4t1 Breast Cancer Model, Jimmy Vo

Biomedical Engineering Undergraduate Honors Theses

Cancer immunotherapy has emerged as a leading front in cancer treatment. In contrast to other treatment methods such as radiation and surgery, immunotherapy trains the patient's body to recognize and eliminate tumors, thus preventing reoccurrence of secondary tumors. IL-12 has been shown to display a potent anti-tumor immune response in mice; however, when clinical trials were conducted, it was shown to be toxic and in some cases fatal when administered systemically.1,2 Because of this, local delivery of IL-12 is under investigation. Our lab has shown that when paired with the polymer chitosan, local, intratumoral (i.t.) injections of IL-12 are retained …

Cationic Starch Synthesis, Development, And Evaluation For Harvesting Microalgae For Wastewater Treatment, Renil John Anthony

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microalgae are the preferred crop for the production of biodiesel. Microalgae are microplants that have the ability to harness sunlight more efficiently than other plants and store 20-80% lipids per g of dry algae in their cells. Microalgae have the extraordinary ability to grow in brackish water or wastewater. Microalgae can be grown in municipal wastewater to uptake phosphorus and nitrogen and remediate the wastewater of these nutrients. Microalgae thus cultivated accomplishes a dual role of wastewater treatment and provides a sustainable feedstock for biofuels and other bioproducts.

This study focused on efficiently harvesting microalgae from water using modified starch. …

Multifunctional Nanophosphors For Tissue Imaging And Drug Delivery, Hongyu Chen

All Dissertations

X-rays have been used for non-invasive high-resolution imaging of thick biological specimens since their discovery in 1895. They are widely used for structural imaging of bone, metal implants, and cavities in soft tissue. Recently, a number of new contrast methodologies have emerged which are expanding X-ray's biomedical applications to functional as well as structural imaging. However, traditional X-ray imaging provides high spatial resolution imaging through tissue but do not measure chemical concentrations. In this dissertation, we describe an X-ray excited optical luminescence (XEOL) technique which uses a scanning X-ray beam to irradiate Gd2O2S phosphors and detect the resulting visible luminescence …

Sustained Release Of Estrogens From Pegylated Nanoparticles For Treatment Of Secondary Spinal Cord Injury, John Barry

All Dissertations

Spinal Cord Injury (SCI) is a debilitating condition which causes neurological damage and can result in paralysis. SCI results in immediate mechanical damage to the spinal cord, but secondary injuries due to inflammation, oxidative damage, and activated biochemical pathways leading to apoptosis exacerbate the injury. The only currently available treatment, methylprednisolone, is controversial because there is no convincing data to support its therapeutic efficacy for SCI treatment. In the absence of an effective SCI treatment option, 17β-estradiol has gained significant attention for its anti-oxidant, anti-inflammatory, and anti-apoptotic abilities, all events associated with secondary. Sadly, 17β-estradiol is associated with systemic adverse …

Highly Sensitive Fiber-Based Devices For Gene And Protein Analysis, Victor Maximov

All Dissertations

Single cell probing has found a number of applications in different areas of research. It can help us to better understand cell-to-cell interactions; it has found numerous applications in immunology, cancer research, detection of pathogenic infections and genetic abnormalities. The single cell analysis is very important in stem cells research and development of cells. The main obstacle in the single cell analysis is the small amount of analyte that a single cell could provide. Another difficulty is connected to the cell-to-cell variability inside the uniform population due to the differences of single cells in size, activity, mitotic stage, and functions. …

A Gamos Plug-In For Geant4 Based Monte Carlo Simulation Of Radiation-Induced Light Transport In Biological Media, Adam K. Glaser, Stephen C. Kanick, Rongxiao Zhang, Pedro Arce, Brian W. Pogue

Dartmouth Scholarship

We describe a tissue optics plug-in that interfaces with the GEANT4/GAMOS Monte Carlo (MC) architecture, providing a means of simulating radiation-induced light transport in biological media for the first time. Specifically, we focus on the simulation of light transport due to the Čerenkov effect (light emission from charged particle's traveling faster than the local speed of light in a given medium), a phenomenon which requires accurate modeling of both the high energy particle and subsequent optical photon transport, a dynamic coupled process that is not well-described by any current MC framework. The results of validation simulations show excellent agreement with …

Controlling Bacterial Persister Cells With Low Level Electric Currents, Henry Lars Peterson

Renée Crown University Honors Thesis Projects - All

Bacterial persister cells present a growing concern as they inherit the ability to tolerate high concentrations of antibiotics and repopulate after an antibiotic treatment leading to chronic diseases. Pseudomonas aeruginosa causes many human infections including skin infections and those associated with burn injuries, and implanted medical devices, and are associated with Cystic Fibrosis. Recently, the Ren Lab developed a novel approach to eliminate persister cells of P. aeruginosa, including those in biofilms, using low level electric currents. To evaluate the safety of this method and to better understand how the underlying elements, this study focused on the cytotoxicity of …

Post-Market Surveillance Of Total Knee Replacement Combining Clinical Outcomes And Quantitative Image Processing Techniques, Leah Nunez

All Theses

Total knee replacement (TKR) is a successful procedure for the relief of pain, correction of deformity, and restoration of function in patients with knee arthritis.1-3 In the United States, the number of primary TKR surgeries performed in 2030 is projected to be between 2,938,000 to 4,136,000 and revision surgeries between 193,000 to 381,000.4 Osteolysis, pain, and aseptic loosening are the most common causes of revision TKR surgery.5 The purpose of this thesis is to complete assessments for post-market surveillance of total knee replacement (TKR) targeting areas for improving polymer bearings through evaluation of clinical outcomes and analysis of prosthesis retrieved …

Development Of An Ex Vivo Tissue Testing System For Three Dimensional Biomechanical Analysis Of Abdominal Aortic Aneurysm, Bradley Johns

All Theses

Abdominal aortic aneurysms (AAA) are localized, progressive dilations of the aortic wall and are the 13th most common cause of death in the United States (~15,000 per year) and surgery is usually recommended when the aneurysm is 5 cm or larger in diameter. Because of this clinical parameter, previous studies of AAA biomechanics have utilized a one-dimensional analysis that focuses solely on changes in wall diameter and have attempted to model geometric changes with mathematical formulas, generally based on the LaPlace equation. This is not sufficient however, as the mechanical behavior of the tissue at sites of aneurysm have been …

Evaluating Mechanical Performance Of Hydrogel-Based Adhesives For Soft Tissue Applications, Nitin Balakrishnan

All Theses

According to the National Center for Health Statistics, an estimated 22 million women have undergone a hysterectomy procedure in the United States. The most common complication during hysterectomies is accidental laceration of the urinary bladder during the surgery with incidence between 0.2-8.3% with the current gold standard wound repair method being sutures. Yet, sutures come with their own limitations in that they necessitate use of a catheter and collection bag during healing due to preventing proper distention of the bladder tissue at normal pressures. The long-term goal of our study is to eliminate the need for suturing by creating a …

Dynamic Transcriptional Response Of Escherichia Coli To Inclusion Body Formation, Faraz Baig

All Theses

Escherichia coli is used intensively for recombinant protein production due to its many unique advantages, but one key challenge with the use of E. coli is the tendency of recombinant proteins to misfold and aggregate into insoluble inclusion bodies (IBs). The presence of IBs stresses cells and can hinder overall growth. Additionally, IBs contain high concentrations of recombinant protein in an inactive form and thus require recovery steps to salvage functional recombinant protein. Currently, no universally effective method exists to prevent IB formation in recombinant E. coli. Further research into the gene expression response to insoluble recombinant protein may …

Evaluation Of Angular Velocity Data From Inertial Measurement Units For Use In Clinical Settings, Chelsea Ex-Lubeskie

All Theses

Evaluating the human gait cycle with inertial measurement units (IMU) may prove beneficial for applications such as diagnoses of musculoskeletal diseases and assessment of rehabilitation regimes. An IMU system is potentially applicable for diagnosing and assessing rehabilitation outcomes for a variety of neuromuscular diseases since it is small, portable, and less expensive than a camera system. IMUs directly measure angular velocity, whereas position data from a camera system must be processed twice to obtain this information. The purpose of this research is to determine repeatability of IMU angular velocity data, and agreement between angular velocity data from an IMU system …

A Regenerative Medicine Approach To Improved Tendon Healing And Repair, Grace Margaret Dion

All Theses

Surgical repair of torn tendons is a common orthopaedic procedure in the United States, with nearly 400,000 repairs occurring annually. Despite improvements in surgical techniques used to re-attach the tendon to its boney insertion, clinically successful outcomes amongst patients are variable and re-tear rates can be exceedingly high. The use of stem cells as an adjunct to surgical repair to aid in improving tendon healing and repair strength has gained much interest amongst the clinical community. Accordingly, many investigators have begun examining the ability of stem cells to differentiate into tenocytes using various methodologies including the application of growth factors …

Characterization Of Potential Wear Sources In Knee Arthroplasty Prostheses After In Vivo Function, Nicole Durig

All Theses

Total joint arthroplasty (TJA) is a common procedure generally performed in patients with osteoarthritis. While TJA continues to be a successful treatment for degenerative joint disease, there are many studies that demonstrate wear and its sequelae as the major limitation of joint replacement longevity. Previous studies have shown that wear debris originates from four main locations: articulating surfaces, modular component surfaces, surfaces of fixation, and adjuvant fixation devices. Each of these possible wear sources can initiate the cascade of failure associated with wear-induced osteolysis and lead to subsequent revision surgery. The objective of this thesis is to characterize the in …