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Microbubble Generation By Piezotransducer For Biological Studies, W. Zhu, M. Alkhazal, M. Cho, S. Xiao

Bioelectrics Publications

Bubbles induced by blast waves or shocks are speculated to be the major cause of damages in biological cells in mild traumatic brain injuries. Microbubble collapse was found to induce noticeable cell detachment from the cell substrate, changes in focal adhesion and biomechanics. To better understand the bubble mechanism, we would like to construct a system, which allows us to clearly differentiate the impact of bubbles from that of shocks. Such a generator needs to be low profile in order to place under a microscope. A piezoelectric transducer system was designed to meet the need. The system uses either a …

Brown Adipogenesis Of Mouse Embryonic Stem Cells In Alginate Microstrands, Andrea Mannarino Unser

Legacy Theses & Dissertations (2009 - 2024)

The ability of brown adipocytes (fat cells) to dissipate energy as heat shows great promise for the treatment of obesity and other metabolic disorders. Employing pluripotent stem cells, with an emphasis on directed differentiation, may overcome many issues currently associated with primary fat cell cultures. However, brown adipocytes are difficult to transplant in vivo due to the instability of fat, in terms of necrosis and neovascularization, once injected. Thus, 3D cell culture systems that have the potential to mimic adipogenic microenvironments are needed, not only to advance brown fat implantation, but also to better understand the role of brown adipocytes …

3d-Bioengineering Of The Conventional Outflow Tract For High Throughput Drug Or Gene Transfer Screening For Glaucoma Treatment, Cula Nolise Dautriche

Legacy Theses & Dissertations (2009 - 2024)

Among ocular pathologies, glaucoma remains the second leading cause of blindness. The molecular mechanisms that lead to glaucoma have been attributed to damage of the conventional outflow tract. Conventional outflow tissues, a composite of the trabecular meshwork and the Schlemm's canal, regulate and maintain homeostatic responses of aqueous humor outflow. In glaucoma, drainage of aqueous humor into the Schlemm's canal is hindered, leading to an increase in intraocular pressure (IOP). That increase in IOP is directly correlated with retinal ganglion cell death, eliminating the relay of visual information to the thalamus and visual cortex, leading to blindness. Although disturbance in …

Programmable Dna Delivery To Cells Using Bioreducible Layer-By-Layer (Lbl) Polyelectrolyte Thin Films, Maria Muniz

Wayne State University Theses

Bioreducible, layer-by-layer (LbL) polyelectrolyte films show great promise for use in biomedical implant and gene-delivery applications. These nanometer-scale thin films can easily be coated onto a variety of implantable surfaces or devices. To achieve proof of concept, HEK-293, NIH/3T3, RAW, and MC3T3 cells were transfected using plasmid DNA with the green fluorescent protein reporter gene (GFP-DNA). In order to optimize transfection, a number of polyelectrolytes and biological components were systematically incorporated into the two similar basic LbL structures. Based on our previous degradation assays, it is shown that cellular interactions in vitro can break down the layers of the thin …

A Novel Function For Fancj Helicase In Microsatellite Stabilization During Replication Stress, Joanna Barthelemy

Browse all Theses and Dissertations

Noncanonical DNA structure-forming sequences, such as hairpin structures, stall replication forks in vivo, expand or contract during DNA replication, and colocalize with chromosome fragile sites. Since the frequency of hairpin formation is higher than the frequency of expansion or contraction, the cell may possess mechanisms to resolve hairpin structures prior to replication fork stalling. One possible activity for hairpin resolution is the FANCJ DNA helicase, known to unwind noncanoncial DNA structures in vitro. Indeed, mutations or loss of any of the nineteen FANC genes, including FANCJ, leads to genome instability and the cancer-prone syndrome Fanconi anemia (FA). To test whether …

Chemotaxis Of Central Nervous System-Derived Tumor Cells Within Controlled Microenvironments, Jennifer Rico Varela

Dissertations and Theses

Medulloblastoma (MB) is a malignant pediatric brain tumor known for its aggressive metastatic potential. Despite the well-documented migration of MB cells to other parts of the brain and spinal column, MB chemotaxis is poorly understood. Herein, we examined the in vitro migratory and cellular responses of MB-derived cells to external signaling of Epidermal Growth Factor (EGF), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF-BB), and the stromal cell-derived factors 1-alpha (SDF-1). Experiments utilized transwell assays and immunocytochemistry to identify receptor activation in MB migration, and used a microfluidic platform to examine directionality, trajectory, and gradient- dependence of motile cells. Data …

Probabilistic Uncertainty Quantification And Experiment Design For Nonlinear Models: Applications In Systems Biology, Vu Cao Duy Thien Dinh

Open Access Dissertations

Despite the ever-increasing interest in understanding biology at the system level, there are several factors that hinder studies and analyses of biological systems. First, unlike systems from other applied fields whose parameters can be effectively identified, biological systems are usually unidentifiable, even in the ideal case when all possible system outputs are known with high accuracy. Second, the presence of multivariate bifurcations often leads the system to behaviors that are completely different in nature. In such cases, system outputs (as function of parameters/inputs) are usually discontinuous or have sharp transitions across domains with different behaviors. Finally, models from systems biology …

Particle Swarm Optimization Using Multiple Neighborhood Connectivity And Winner Take All Activation Applied To Biophysical Models Of Inferior Colliculus Neurons, Brandon S. Coventry

Open Access Theses

Age-related hearing loss is a prevalent neurological disorder, affecting as many as 63% of adults over the age of 70. The inability to hear and understand speech is a cause of much distress in aged individuals and is becoming a major public health concern as age-related hearing loss has also been correlated with other neurological disorders such as Alzheimer's dementia. The Inferior Colliculus (IC) is a major integrative auditory center, receiving excitatory and inhibitory inputs from several brainstem nuclei. This complex balance of excitation and inhibition gives rise to complex neural responses, which are measured in terms of firing rate …

Reverse Protein Engineering Of Firefly Luciferase, Kahler Bugtong, Skyler Herczeg, Abraham Munoz, Alexandra Obata

Bioengineering Senior Theses

Firefly luciferase is a bioluminescent protein commonly used as a bioluminescent tag in biological studies and applications. However, because the protein is fairly large in size, it is sometimes larger than the molecules it is intended to measure and is therefore not a sufficient tag in smaller applications. The active site of firely luciferase is also not well understood, making it difficult to engineer the protein without affecting its bioluminescent activity. In this paper, we discuss the experimental methods of Reverse Protein Engineering: a bioengineering technology that reduces the size of a protein while retaining its original function. This involves …

Submicron-Resolution Photoacoustic Microscopy Of Endogenous Light-Absorbing Biomolecules, Chi Zhang

All Theses and Dissertations (ETDs)

Photoacoustic imaging in biomedicine has the unique advantage of probing endogenous light absorbers at various length scales with a 100% relative sensitivity. Among the several modalities of photoacoustic imaging, optical-resolution photoacoustic microscopy (OR-PAM) can achieve high spatial resolution, on the order of optical wavelength, at <1 mm depth in biological tissue (the optical ballistic regime). OR-PAM has been applied successfully to structural and functional imaging of blood vasculature and red blood cells in vivo. Any molecules which absorb sufficient light at certain wavelengths can potentially be imaged by PAM. Compared with pure optical imaging, which typically targets fluorescent markers, label-free PAM avoids the major concerns that the fluorescent labeling probes may disturb the function of biomolecules and may have an insufficient density. This dissertation aims to advance label-free OR-PAM to the subcellular scale.

The first part of this dissertation describes the technological advancement of PAM yielding high spatial resolution in 3D. The lateral resolution was improved by using optical objectives with high numerical apertures for optical focusing. The axial resolution was improved by using broadband ultrasonic transducers for ultrasound detection. We achieved 220 nm lateral resolution in transmission …

Computational Investigation On The Structural Properties Of Neurofilaments And Their Sidearms, Lakshmi Jayanthi

Wayne State University Dissertations

Neurofilaments (NFs) are class IV intermediate filaments, abundantly found in the large myelinated axons. They are the key determinants of axonal diameter and consequently the nerve conduction properties. On the other hand, abnormal NF accumulation has been the hallmark of debilitating neurodegenerative disorders. NF compaction is also one of the pathological manifestations of traumatic axonal Injury. However, the exact relation between the disorganized NFs and the etiology of the neurodegenerative disorders is yet to be fully understood. NFs are assembled from three subunits: Low (NFL), Medium (NFM) and Heavy (NFH). These subunits are characterized by a common alpha helical rod …

Layered Long Term Co-Culture Of Hepatocytes And Endothelial Cells On A Transwell Membrane: Toward Engineering The Liver Sinusoid, Young Bok (Abraham) Kang, Siddhartha Rawat, Joseph Cirillo, Michael Bouchard, Hongseok (Moses) Noh

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

This paper presents a novel liver model that mimics the liver sinusoid where most liver activities occur. A key aspect of our current liver model is a layered co-culture of primary rat hepatocytes (PRHs) and primary rat liver sinusoidal endothelial cells (LSECs) or bovine aortic endothelial cells (BAECs) on a transwell membrane. When a layered co-culture was attempted with a thin matrigel layer placed between hepatocytes and endothelial cells to mimic the Space of Disse, the cells did not form completely separated monolayers. However, when hepatocytes and endothelial cells were cultured on the opposite sides of a transwell membrane, PRHs …

Automated Methods To Determine Electrospun Fiber Alignment And Diameter Using The Radon Transform, Nicholas J. Schaub, Sean J. Kirkpatrick, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Recent evidence demonstrates the ability to change cell function by altering the physical properties of electro spun scaffolds, but many studies still do not characterize electro spun fiber alignment and diameter. To aid in the reporting of these crucial properties, we demonstrate two methods of quantifying electro spun fiber alignment with one method capable of determining electro spun fiber diameter. The first method assesses fiber alignment in a scanning electron microscopy image using the Radon Transform (RT) to calculate the entropy of the fibers in the image. The RT entropy method was more sensitive than a commonly used Fast Fourier …

Techno-Economic And Fluid Dynamics Analysis For Growing Microalgae With The Intent Of Producing Biofuel Using A System Model, Leah R. Raffaeli

Electronic Theses and Dissertations

Techno-economic and systems studies on microalgal growth scenarios to date are abbreviated and missing a number of important variables. By including these variables in a detailed model integrating biology, chemistry, engineering, and financial aspects, a more defined systems analysis is possible. Through optimizing the model productivity based on the resulting net profit, the system analysis results in a more accurate assessment of environmental and economic sustainability of specific algal growth scenarios. Photobioreactor algal growth scenario optimization in the system model has resulted in realistic engineering design requirements based on algal growth requirements and fluid dynamics analysis. Results show feasibility for …

A Novel Microfluidic Enrichment Technique For Carbonylated Proteins, Bryant C. Hollins

Doctoral Dissertations

Proteins are the building blocks of cells in living organisms, and are composed of amino acids. The expression of proteins is regulated by the processes of transcription and translation. Proteins undergo post-translational modifications in order to dictate their role physiologically within a cell.

Not all post-translational modifications are beneficial for the protein or the cell. One type of post-translational modification, called carbonylation, irreversibly places a carbonyl group onto an amino acid residue, most commonly proline, lysine, arginine, and threonine. This modification can have severe consequences physiologically, including loss of solubility, loss of function, and protein aggregation.

Carbonylated proteins have commonly …

Subnanosecond Exposure Systems For Biological Studies, Jongbong Nah

Electrical & Computer Engineering Theses & Dissertations

The research of bioelectrics has expanded to subnanosecond pulse region and entered a new domain of biophysics of cell interaction with ultra-short and intense electric fields. As subnanosecond pulses may be delivered by antennas to the human body and is very attractive to the medical community, the study of subnanosecond pulse effects calls for exposure systems for both cells and tissues. Two systems were designed in the scope of this thesis, used for cells and tissues respectively. The exposure system designed for cell exposure is a cuvette consisting of two parallel aluminum gaps. This cuvette is placed in a coaxial …

Soft Microenvironments Promote The Early Neurogenic Differentiation But Not Self-Renewal Of Human Pluripotent Stem Cells, Albert Keung, Prashanth Asuri, Sanjay Kumar, David Schaffer

Bioengineering

Human pluripotent stem cells (hPSCs) are of great interest in biology and medicine due to their ability to self-renew and differentiate into any adult or fetal cell type. Important efforts have identified biochemical factors, signaling pathways, and transcriptional networks that regulate hPSC biology. However, recent work investigating the effect of biophysical cues on mammalian cells and adult stem cells suggests that the mechanical properties of the microenvironment, such as stiffness, may also regulate hPSC behavior. While several studies have explored this mechanoregulation in mouse embryonic stem cells (mESCs), it has been challenging to extrapolate these findings and thereby explore their …

Hydrodynamic Focused Passive Separation Under Continuous Flow In A Microfluidic Chip, Jad Kanbar

Master's Theses

A continuous flow, passive separation device was designed using an equivalent circuit to create variable flow rates for hydrodynamic focusing to drain channels and collection outlets. By varying the diameter of the sample inlet connection into the reservoir, the particle position was influenced significantly, which enabled desired separations. Additionally it was noted that the relative, horizontal position of the inlet also had a significant influence on particle position within the device. A dimensionless number, the Characteristic Sample Inlet, was developed to relate geometric properties of the inlet reservoir to downstream particle distribution. It was found that a 2:1 ratio between …

Nanopillar Based Electrochemical Biosensor For Monitoring Microfluidic Based Cell Culture, Rajan Gangadharan

All Dissertations

In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events.
With this motivation we developed a highly sensitive, selective and stable microfluidic …

Nonosecond Pulsed Electric Field Induced Changes In Dielectric Properties Of Biological Cells, Jie Zhuang

Electrical & Computer Engineering Theses & Dissertations

Nanosecond pulsed electric field induced biological effects have been a focus of research interests since the new millennium. Promising biomedical applications, e.g. tumor treatment and wound healing, are emerging based on this principle. Although the exact mechanisms behind the nanosecond pulse-cell interactions are not completely understood yet, it is generally believed that charging along the cell membranes (including intracellular membranes) and formation of membrane pores trigger subsequent biological responses, and the number and quality of pores are responsible for the cell fate. The immediate charging response of a biological cell to a nanosecond pulsed electric field exposure relies on the …

Synergistic Effect Of Subnanosecond Pulsed Electric Fields And Temperature On The Viability Of Biological Cells, James Thomas Camp

Electrical & Computer Engineering Theses & Dissertations

Pulsed electric fields have been used to induce a biological response in cells, and at sufficient energy, can cause cell death. By reducing the pulse duration from presently used nanosecond to subnanosecond ranges, the electric field can be delivered to biological tissue non-invasively by the use of an antenna instead of electrodes, such as needles. Studies have previously been completed in which the aim was to determine the energy density (electric field strength, number of pulses) required to induce cell death with 800 ps pulses. Based on this data, it was concluded that for pulse durations of 200 ps, with …

Biomechanics, Brooke A. Slavens, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Biomechanics is a vast discipline within the field of Biomedical Engineering. It explores the underlying mechanics of how biological and physiological systems move. It encompasses important clinical applications to address questions related to medicine using engineering mechanics principles. Biomechanics includes interdisciplinary concepts from engineers, physicians, therapists, biologists, physicists, and mathematicians. Through their collaborative efforts, biomechanics research is ever changing and expanding, explaining new mechanisms and principles for dynamic human systems. Biomechanics is used to describe how the human body moves, walks, and breathes, in addition to how it responds to injury and rehabilitation. Advanced biomechanical modeling methods, such as inverse …

Effect Of Extracellular Matrix (Ecm) Protein Micropatterns On The Behavior Of Human Neuroblastoma Cells, Ishwari Poudel

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Recent advances in patterning techniques and emerging surface microtechnologies have allowed cell micropatterning to control spatial location of the cells on a surface as well as cell shape, attachment area, and number of contacting neighbor cells. These parameters play important roles in cell cellular behaviors. Cell micropatterning has thus become one of the most important strategies for biomedical applications, such as, tissue engineering, diagnostic immunoassays, lab-on-chip devices, bio-sensing, etc., and cell biology studies as well. For neuronal cells, there have been attempts to distribute neuronal cells on specific patterns to control cell-to-cell interaction. However, there have been very limited understanding …

Manipulating Cellular Growth Responses To Patterning, Apoptotic, And Environmental Cues, James N. Mcnamara

Doctoral Dissertations

In this work, various methods of controlling cell growth are examined. Cell-cell interaction, apoptotic cues, three dimensional scaffolds, and non-adherent environments are evaluated for their ability to affect the differentiation, morphology, and growth rate of different cell types. Previous work has shown that cell growth and cell morphology can be influenced by patterns of polymers coated on surfaces in two dimensions, designated here as the x and y dimensions of a standard Cartesian coordinate system. Tissue engineering and regenerative medicine studies have shown limited success in modifying growth in the third, z dimension. This work considers not only the x, …

Modeling And Its Numerical Method For Micro-Scaled Diffusion -Reaction Systems In The Neuromuscular Junction, Abdul Khaliq

Doctoral Dissertations

The main subject of this research is the neuromuscular junction (NMJ). The NMJ is a biological structure composed of the interface between a neuron and a muscle cell. Currently, there is not a fully three dimensional model of diffusion-reaction processes occurring in the NMJ. Developing a useful predictive model of this structure will assist in the therapeutic efforts to restore and rehabilitate NMJ function to humans and in developing strategies to prevent damage to the NMJ. This research work developed 1D mass transport and full 3D reaction diffusion models. A new finite difference scheme is presented for solving 1D mass …

Design, Fabrication, And Implementation Of A Single-Cell Capture Chamber For A Microfluidic Impedance Sensor, Joshua-Jed Doria Fadriquela

Master's Theses

A microfluidic device was created for single-cell capture and analysis using polydimethylsiloxane (PDMS) channels and a glass substrate to develop a microfluidic single-cell impedance sensor for cell diagnostics. The device was fabricated using photolithography to create a master mold which in turn will use soft lithography to create the PDMS components for constant device production. The commercial software, COMSOLTM Multiphysics, was used to quantify the fluid dynamics in shallow micro-channels.

The device will be able to capture a cell and sequester it long enough to enable measurement of the impedance spectra that can characterize cell. The proposed device will be …

Site-Specific Deoxyribonucleic Acid Modifications For Use With Chemical Cages, John P. Casey Jr

Honors Capstones

No abstract provided.

Development Of An In-Vitro Tissue Engineered Blood Vessel Mimic Using Human Large Vessel Cell Sources, Dimitri E. Delagrammaticas

Master's Theses

Tissue engineering is an emerging field that offers novel and unmatched potential medical therapies and treatments. While the vast aim of tissue engineering endeavors is to provide clinically implantable constructs, secondary applications have been developed to utilize tissue-engineered constructs for in-vitro evaluation of devices and therapies. Specifically, in-vitro blood vessel mimics (BVM) have been developed to create a bench-top blood vessel model using human cells that can be used to test and evaluate vascular disease treatments and intravascular devices. Previous BVM work has used fat derived human microvascular endothelial cells (EC) sodded on an ePTFE scaffold. To create a more …

Biotechnology For Immune Cell Detection And Evaluation : Devices Specifically Designed To Capture, Detect Or To Evaluate Alterations In Leukocyte Structure And Function, Thomas Joseph Zieziulewicz

Legacy Theses & Dissertations (2009 - 2024)

The advent of Nano-biotechnology has opened a whole new area of biological study that has allowed us to pattern, manipulate, separate, evaluate and detect biological structures and functions that were previously not possible. This dissertation will describe different types of micro-fabricated devices that were designed to quantify and/or evaluate the functional activities of cells of the immune system. The micro-fabricated devices were developed in collaboration with our colleagues at Princeton University as part of our Cellular Micro-dynamics Program of the Nanobiotechnology Center (NBTC) at Cornell University.

Gene Synthesis, Cloning, Expression, Purification And Biophysical Characterization Of The C2 Domain Of Human Tensin, Kiran Sukumar Gajula

Doctoral Dissertations

Tensin is a large "docking" protein found in the adhesive junctions of animal cells and recruited early in the development of cell-substrate contacts. There it binds to the cytoplasmic domain of integrin β1 and caps the barbed ends of filamentous actin. This forms a rational basis for its implication in a direct role in the mechanics of membrane-cytoskeleton interactions. Tensin provides a physical link between the actin cytoskeleton, integrins, and other proteins at the cell-substrate contacts. Its overall biochemical properties are a function of its domain composition and architecture, i.e., the domains that are present and their relative positions in …