Biomedical Engineering and Bioengineering Commons^™

Device Engineering For Infectious Disease Diagnosis Using Isothermal Dna Amplification And Lateral Flow Detection, Kristina Roskos

KGI Theses and Dissertations

Technologies that enable infectious diseases diagnosis in low-resource settings could greatly facilitate effective treatment and containment of such diseases. Nucleic acid amplification testing can be used to identify pathogens, but typically requires highly-trained personnel and large, expensive lab equipment, neither of which is available in low-resource settings. Our overall goal is to develop a portable diagnostic system that utilizes a low-cost, disposable, mesofluidic cartridge and a handheld electronics unit to perform fully-integrated nucleic acid testing at the point of care in low-resource settings. As a first step toward this goal, we developed a subunit to execute isothermal nucleic acid amplification …

Senior Design Report: Workstation For Paige Librandi, Ana C. Groff

Honors Scholar Theses

The workstation senior design project is a wheelchair accessible, left-side desk. It is for the client, Paige Librandi, who has cerebral palsy and is left-hand dominant. The purpose of the desk is to provide multitasking features to create an efficient work space for Paige to work on. It aims to also increase her independence by incorporating tools that prevent items from falling off the floor where she can't retrieve them.

The workstation design has several features, including a rotating surface, sliding bookcase, and gliding platform. These tools provide simultaneous work spaces and storage in a small amount of space to …

Biomedical Photoacoustic Imaging Using Gas-Coupled Laser Acoustic Detection, Jami Johnson

Student Research Initiative

Several detection methods have been explored for photoacoustic and ultrasound imaging of biological tissues. Piezoelectric transducers are commonly used, which require contact with the sample to be imaged and have limiting bandwidth characteristics. Interferometry detection exhibits improved bandwidth characteristics and resolution, yet generally require complicated optics and the incorporation of a contacting reflective medium. In this paper, we report the use of a noncontact photoacoustic imaging system that does not require the use of a reflective layer. A simple, robust technique known as gas-coupled laser acoustic detection is used, which has previously been applied to evaluation of composite materials. This …

Automatic Segmentation Of Pressure Images Acquired In A Clinical Setting, Anathea Pepperl

Theses and Dissertations

One of the major obstacles to pressure ulcer research is the difficulty in accurately measuring mechanical loading of specific anatomical sites. A human motion analysis system capable of automatically segmenting a patient's body into high-risk areas can greatly improve the ability of researchers and clinicians to understand how pressure ulcers develop in a hospital environment. This project has developed automated computational methods and algorithms to analyze pressure images acquired in a hospital setting. The algorithm achieved 99% overall accuracy for the classification of pressure images into three pose classes (left lateral, supine, and right lateral). An applied kinematic model estimated …

Modernization Of The Mock Circulatory Loop: Advanced Physical Modeling, High Performance Hardware, And Incorporation Of Anatomical Models, Charles Taylor

Theses and Dissertations

A systemic mock circulatory loop plays a pivotal role as the in vitro assessment tool for left heart medical devices. The standard design employed by many research groups dates to the early 1970's, and lacks the acuity needed for the advanced device designs currently being explored. The necessity to update the architecture of this in vitro tool has become apparent as the historical design fails to deliver the performance needed to simulate conditions and events that have been clinically identified as challenges for future device designs. In order to appropriately deliver the testing solution needed, a comprehensive evaluation of the …

Computational Capabilities Of Leaky Integrate-And-Fire Neural Networks For Liquid State Machines, Amin Almassian, Christof Teuscher

Student Research Symposium

We analyze the computational capability of Leaky Integrate-and-Fire (LIF) Neural Networks used as a reservoir (liquid) in the framework of Liquid State Machines (LSM). Maass et. al. investigated LIF neurons in LSM and their results showed that they are capable of noise-robust, parallel, and real-time computation. However, it still remains an open question how the network topology affects the computational capability of a reservoir. To address that question, we investigate the performance of the reservoir as a function of the average reservoir connectivity. We also show that the dynamics of the LIF reservoir is sensitive to changes in the average …

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 …

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 …

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 …

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

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 …

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 …

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 …

Highly Sensitive Method For Detecting And Separating Pathogens Using Paramagnetic Particles And A Micro-Fluidic System, William Ryan

Biomedical Engineering Undergraduate Honors Theses

Water is one of the most important compounds on Earth. If a water supply is contaminated with a pathogen, it can have devastating results to an individual or a community. This research is directed at constructing an easily reproducible procedure that could increase the sensitivity of detecting and separating bacteria from the current limits of about 100 cells to 10-20 cells per sample with a ultimate goal of a single cell detection. Here, we report a micro-fluidic system to magnetically capture pathogenic bacteria in water followed by rapid impedance detection using Escherichia coli K-12 as a model bacterium. Paramagnetic beads …

Comparing Decellularized Muscle Tissue With An Engineered Muscle Biomaterial, Katelin Cherry

Biomedical Engineering Undergraduate Honors Theses

Decellularized tissues composed of extracellular matrix are commonly used for tissue transplantations but this method has many limitations. An alternative approach is to create an extracellular matrix by seeding degradable foams with cells, culturing these foams to allow extracellular matrix to be secreted from the cells, then washing away the degradable foam to collect the material that is produced. This study was interested in comparing decellularized skeletal muscle tissue to an engineered biomaterial that was seeded with skeletal muscle myoblast cells. Collagen content of decellularized tissue and engineered biomaterial were quantified using a hydroxyproline assay to compare the two samples. …

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 …

Aluminium-Free Glass Polyalkenoate Cements: Ion Release And In Vitro Antibacterial Efficacy, A. W. Wren, J. P. Hansen, S. Hayakawa, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements (GPCs) have exhibited potential as bone cements. This study investigates the effect of substituting TiO₂ for SiO₂ in the glass phase and the subsequent effect on cement rheology, mechanical properties, ion release and antibacterial properties. Glass characterization revealed a reduction in glass transition temperature (T_g) from 685 to 669 C with the addition of 6 mol % TiO₂ (AT-2). Magic angle spinning nuclear magnetic resonance (MAS-NMR) revealed a shift from -81 ppm to -76pmm when comparing a Control glass to AT-2, indicating de-polymerization of the Si network. The incorporation of TiO_{2 …}

Study Of Immobilizing Cadmium Selenide Quantum Dots In Selected Polymers For Application In Peroxyoxalate Chemiluminescence Flow Injection Analysis, Christopher S. Moore

Electronic Theses and Dissertations

Two batches of CdSe QDs with different sizes were synthesized for immobilizing in polyisoprene (PI), polymethylmethacrylate (PMMA), and low-density polyethylene (LDPE). The combinations of QDs and polymer substrates were evaluated for their analytical fit-for-use in applicable immunoassays. Hydrogen peroxide standards were injected into the flow injection analyzer (FIA) constructed to simulate enzyme-generated hydrogen peroxide reacting with bis-(2,4,6-trichlorophenyl) oxalate.

Linear correlations between hydrogen peroxide and chemilumenscent intensities yielded regression values greater than 0.9750 for hydrogen peroxide concentrations between 1.0 x 10^-4 M and 1.0 x 10^-1 M. The developed technique’s LOD was approximately 10 ppm. Variability of the prepared …