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Articles 1 - 15 of 15

Full-Text Articles in Biomedical Engineering and Bioengineering

Improvement Of Fluorescence-Based Microfluidic Dna Analyzers, Collin Tranter Apr 2017

Improvement Of Fluorescence-Based Microfluidic Dna Analyzers, Collin Tranter

Doctoral Dissertations

A tremendous effort continues in the development of micro-total-analysis-systems; in support of this, many chemical passivation methods have been developed to enhance the biocompatibility of such microfluidic systems. However, the suitability of these passivation techniques to many fluorescence-based assays still remains inconsistent. This part of this work is focused on the performance of a third generation intercalating DNA dye when used within microfluidic devices treated with a select variety of passivating coatings. The results of these tests indicate that passivation coatings which are intended to shed DNA based on electrostatic repulsion will in fact imbibe the fluorescent DNA intercalating dye ...


Nano Clay-Enhanced Calcium Phosphate Cements And Hydrogels For Biomedical Applications, Udayabhanu Jammalamadaka Jul 2016

Nano Clay-Enhanced Calcium Phosphate Cements And Hydrogels For Biomedical Applications, Udayabhanu Jammalamadaka

Doctoral Dissertations

Biomaterials are used as templates for drug delivery, scaffolds in tissue engineering, grafts in surgeries, and support for tissue regeneration. Novel biomaterial composites are needed to meet multifaceted requirements of compatibility, ease of fabrication and controlled drug delivery. Currently used biomaterials in orthopedics surgeries suffer limitations in toxicity and preventing infections. Polymethyl methacrylate (PMMA) used as bone cement suffers from limitations of thermal necrosis and monomer toxicity calls for development of better cementing biomaterials. A biodegradable/bioresorbable cement with good mechanical properties is needed to address this short coming. Metal implants used in fixing fractures or total joint replacement needs ...


Mutlifunctional Platforms For Gene And Drug Delivery For Cancer Therapy, Jeffery J. Ambrose Jr. Apr 2016

Mutlifunctional Platforms For Gene And Drug Delivery For Cancer Therapy, Jeffery J. Ambrose Jr.

Doctoral Dissertations

The National Cancer Institute and the American Cancer Society estimate that 1.6 million new cancer incidences and over half a million cancer related deaths occur annually [1][2]. Cancer the second most common cause of death in the United States [1], [2]. Although the causes of cancer can vary depending on cell type, all or almost all instances of cancer arise from a mutation or from an abnormal activation of the cellular genes that control cell growth and mitosis [3].

Treatment of a given cancer type depends on the subtype, stage and progression of the cancer. Varieties of cancer ...


Engineering Microenvironments To Modulate Calcium Information Processing In Neuronal Cells, Kinsey Cotton Kelly Jan 2013

Engineering Microenvironments To Modulate Calcium Information Processing In Neuronal Cells, Kinsey Cotton Kelly

Doctoral Dissertations

Tissue engineered microenvironments were constructed to test the effects glial cells have on calcium information processing, and to mimic conditions in vivo for tumor invasion and residual cancer after resection of tumor. Submaximal, nM, glutamate (GLU) stimuli were applied to the engineered environments, and the resulting calcium dynamic behavior of neuronal cells was measured to help predict and interpret chaotic systems in the experimental realm. Calcium is a key signaling ion which signals through the N-methyl-D-aspartate (NMDA) glutamate receptor on the neuronal membrane. GLU binding to the NMDA receptor (NMDAR) causes a large and dynamic increase in neuronal intracellular calcium ...


The Contribution Of Oxidative Stress In The Protein Damage And Dna Lesion In Alzheimer's Disease Neuropathology, Cheng Zhang Oct 2012

The Contribution Of Oxidative Stress In The Protein Damage And Dna Lesion In Alzheimer's Disease Neuropathology, Cheng Zhang

Doctoral Dissertations

Glutathione (GSH) plays an essential role in the intracellular antioxidant defense against the oxidant radicals, especially the ·OH radical. To understand the early and progressive cellular changes in Alzheimer's disease (AD) development, we investigated reduced glutathione/oxidized glutathione (GSH/GSSG) status in a double mutated AD transgenic mouse model (B6.Cg-Tg), which carries Swedish amyloid precursor protein mutation (APPswe) and exon 9 deletion of the PSEN1 gene. Likewise, S-glutathionylation (Pr-SSG) is a specific post-translational modification (PTM) of cysteine residues by the addition of glutathione. S-glutathionylated proteins induced by oxidative stress play an essential role in understanding the ...


Real-Time Analysis Of Brain Tumor Cell Dynamics: Novel Thermoelectric Detection Of L-Glutamate And Cell Metabolism Using Microfluidics, Siva Mahesh Tangutooru Oct 2012

Real-Time Analysis Of Brain Tumor Cell Dynamics: Novel Thermoelectric Detection Of L-Glutamate And Cell Metabolism Using Microfluidics, Siva Mahesh Tangutooru

Doctoral Dissertations

This study describes the design, fabrication and applications of a novel thermoelectric microfluidic bio-sensor. The bio-sensor is used for real time detection of the L-glutamate (L-glu) dynamics and metabolism for brain tumor cells immobilized in a microfluidic device. The microfluidic device is fabricated using a polymer/glass laminating technique (Xurography). An antimony-bismuth thin-film thermopile (primary sensing element) is integrated to the microfluidic device. The brain tumor cells are immobilized over the thermopile covering measuring and reference junctions of the thermopile using a poly-l-lysine coating layer. L-glutamate oxidase (L-GLOD) is immobilized over the measuring junctions of the thermopile prior to the ...


A Hybrid Brain-Computer Interface Based On Motor Intention And Visual Working Memory, Ching-Chang Kuo Oct 2012

A Hybrid Brain-Computer Interface Based On Motor Intention And Visual Working Memory, Ching-Chang Kuo

Doctoral Dissertations

Non-invasive electroencephalography (EEG) based brain-computer interface (BCI) is able to provide alternative means for people with disabilities to communicate with and control over external assistive devices. A hybrid BCI is designed and developed for following two types of system (control and monitor).

Our first goal is to create a signal decoding strategy that allows people with limited motor control to have more command over potential prosthetic devices. Eight healthy subjects were recruited to perform visual cues directed reaching tasks. Eye and motion artifacts were identified and removed to ensure that the subjects' visual fixation to the target locations would have ...


Micro, Nano Encapsulation Methods For Sustained Release Drug Formulations And Biomimetic Applications, Shantanu Balkundi Jul 2009

Micro, Nano Encapsulation Methods For Sustained Release Drug Formulations And Biomimetic Applications, Shantanu Balkundi

Doctoral Dissertations

The Layer-by-Layer (LbL) assembly technique was used to obtain a new type of protein/polyphenol microcapsule based on naturally occurring polyphenol (-)-epigallocatechin gallate (EGCG) and gelatin, type A. The dependence of permeability on the molecular weight of permeating substances was studied and compared with commonly used polyallylamine/polystyrene sulfonate capsules. A quartz crystal microbalance was used to monitor the regularities of EGCG adsorption in alternation with type A and B Gelatins and electrophoretic mobility measurements were used that indicated that the nature of assembly was dependent on Gelatin properties. It was shown that EGCG retains its antioxidant activity in the ...


Nanoengineered Templates For Controlled Delivery Of Bioactive Compounds, Nalinkanth Ghone Veerabadran Jul 2008

Nanoengineered Templates For Controlled Delivery Of Bioactive Compounds, Nalinkanth Ghone Veerabadran

Doctoral Dissertations

The significance of any drugs, therapeutic proteins, or any bioactive compounds, is based not only on their effects on diseases but also on how specifically, how readily, how controllable and how prolonged their effects on the disease without having any side effects. Thus the techniques involved in the drug encapsulation and its controlled release for a longer duration of time form one of the important processes of drug reformulation. In recent years nanoparticles have created overwhelming attention for delivering drugs by nanoencapsulation. The smaller size of nanoparticles has longer circulation time and higher cellular uptake when compared with larger size ...


Gene Synthesis, Cloning, Expression, Purification And Biophysical Characterization Of The C2 Domain Of Human Tensin, Kiran Sukumar Gajula Oct 2007

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 ...


Drug Loading And Release From Polypeptide Multilayer Nanofilms, Yang Zhong Jan 2007

Drug Loading And Release From Polypeptide Multilayer Nanofilms, Yang Zhong

Doctoral Dissertations

Polypeptides, linear macromolecules, are formed from amino acid residues by linkage of peptide bonds. Proteins are polypeptides too, with more complex conformations contributing to specific functionalities. Disulfide bonds are very important to maintain the structure and functions of proteins, which will form between two cysteine (Cys) residues under oxidizing circumstance.

Cys containing polypeptides are designed and synthesized by F-moc (9-Fluorenylmethyloxycarbonyl) chemistry. The number and position of Cys residues can be controlled by amino acid sequences design and following peptide synthesis, which is important to gain insights on the nature of polyelectrolyte multilayer film assembly and stability.

Both commercial and designed ...


Molecular Modeling Of Proteins And Peptides Related To Cell Attachment In Vivo And In Vitro, Wanhua Zhao Jul 2006

Molecular Modeling Of Proteins And Peptides Related To Cell Attachment In Vivo And In Vitro, Wanhua Zhao

Doctoral Dissertations

Polypeptides constitute half of the dry mass of the cell, they form the bulk of the extracellular matrix (ECM), and they are a common element of extra- and intracellular signaling pathways. There is increasing interest in the development of computational methods in polypeptide and protein engineering on all length scales. This research concerns the development of computational methods for study of polypeptide interactions related to cell attachment in vivo and in vitro.

Polypeptides are inherently biocompatible, and an astronomical range of unique sequences can be designed and realized in massive quantities by modern methods of synthesis and purification. These macromolecules ...


Development Of Self-Assembled Monolayer-Based Cell Culture Platform Towards Fabrication Of A Three-Dimensional Bioreactor, Rajendra Kandoor Aithal Apr 2006

Development Of Self-Assembled Monolayer-Based Cell Culture Platform Towards Fabrication Of A Three-Dimensional Bioreactor, Rajendra Kandoor Aithal

Doctoral Dissertations

The extracellular matrix (ECM) plays an important role in regulating a number of cellular properties and functions like cell differentiation, cell synthesis and degradation, cell viability and proliferation, cell function, and cell aging. Surface modification of planar substrates with self-assembled monolayers (SAMs) is a promising technique to achieve stable ECMs.

In this work, substrates such as silicon (Si), gallium arsenide (GaAs) and indium tin oxide (ITO) substrates were modified with SAMS containing amino (-NH2), methyl (-CH3), thiol (-SH) and carboxylic (-COOH) end groups and characterized using contact angle measurements, surface infrared (IR) spectroscopy and atomic force microscopy (AFM). Different cell ...


A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu Jul 2004

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single ...


Fabrication, Characterization, And Chemical Sensing Of Silicon Dioxide Microcantilevers, Yanjun Tang Apr 2004

Fabrication, Characterization, And Chemical Sensing Of Silicon Dioxide Microcantilevers, Yanjun Tang

Doctoral Dissertations

The objective of this work is to design and fabricate an advanced silicon dioxide microcantilever sensor and to investigate chemical and biological sensing by microtechnology.

Microcantilever sensor technology has many advantages including fast response time, lower cost of fabrication, the possibility of sensor arrays with small overall dimensions, the ability to explore microenvironments, and improved portability for field applications. For all of these advantages, microcantilever chemical and biological sensors have drawn more and more attention.

So far, all other microcantilevers were designed and fabricated for AFM applications. We developed a novel SiO2 microcantilever especially for chemical and biological sensor applications ...