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Articles 1 - 15 of 15

Full-Text Articles in Biomedical Engineering and Bioengineering

Biomarker Detection At Risk Forecasting Level Using Metal-Enhanced Fluorescence Combined With Surface Acoustic Wave, Jun Liu Nov 2016

Biomarker Detection At Risk Forecasting Level Using Metal-Enhanced Fluorescence Combined With Surface Acoustic Wave, Jun Liu

Graduate Theses and Dissertations

In this paper, metal-enhanced fluorescence (MEF) technique is used to lower the detection limit of carcinoembryonic antigen (CEA) which is able to be utilized in forecasting the risk of having certain kinds of cancers, especially colon and rectal cancer. By incubating silver nanocubes (Ag NCs) on the surface of the chips, the detection limit goes down to below 1ng/mL of CEA. Also, when combining MEF with surface acoustic wave (SAW) devices, the incubation time between antigen and antibody will decrease significantly with the fluorescence signal keeping similar or higher level.


Subcellular And In-Vivo Nano-Endoscopy, Surya Venkatasekhar Cheemalapati, John Winskas, Hao Wang, Karthik Konnaiyan, Arseny Zhdanov, Alison Roth, Swamy Rakesh Adapa, Andrew Deonarine, Rays H. Y. Jiang, Anna Pyayt Oct 2016

Subcellular And In-Vivo Nano-Endoscopy, Surya Venkatasekhar Cheemalapati, John Winskas, Hao Wang, Karthik Konnaiyan, Arseny Zhdanov, Alison Roth, Swamy Rakesh Adapa, Andrew Deonarine, Rays H. Y. Jiang, Anna Pyayt

Chemical and Biomedical Engineering Faculty Publications

Analysis of individual cells at the subcellular level is important for understanding diseases and accelerating drug discovery. Nanoscale endoscopes allow minimally invasive probing of individual cell interiors. Several such instruments have been presented previously, but they are either too complex to fabricate or require sophisticated external detectors because of low signal collection efficiency. Here we present a nanoendoscope that can locally excite fluorescence in labelled cell organelles and collect the emitted signal for spectral analysis. Finite Difference Time Domain (FDTD) simulations have shown that with an optimized nanoendoscope taper profile, the light emission and collection was localized within ~100 nm ...


Nano-Photonic Waveguides For Chemical And Biomedical Sensing, Surya Venkatasekhar Cheemalapati May 2016

Nano-Photonic Waveguides For Chemical And Biomedical Sensing, Surya Venkatasekhar Cheemalapati

Graduate Theses and Dissertations

In this dissertation, advances in the fields of Photonics, and Plasmonics, and specifically, single cell analysis and waveguide sensing will be addressed. The first part of the dissertation is on Finite Difference Time Domain (FDTD) optimization and experimental demonstration of a nano-scale instrument that allows sensing at the cellular and subcellular levels. A new design of plasmonic coupler into a nanoscale waveguide is proposed and optimized using FDTD simulations. Following this, a subcellular nanoendoscope that can locally excite fluorescence in labelled cell organelles and collect the emitted fluorescent light for detailed spectrum analysis is fabricated and tested. The nanoendoscope has ...


Age-Related Hearing Loss: Prevention Of Threshold Declines, Cell Loss And Apoptosis In Spiral Ganglion Neurons, Robert D. Frisina, Bo Ding, Xiaoxia Zhu, Joseph P. Walton Jan 2016

Age-Related Hearing Loss: Prevention Of Threshold Declines, Cell Loss And Apoptosis In Spiral Ganglion Neurons, Robert D. Frisina, Bo Ding, Xiaoxia Zhu, Joseph P. Walton

Chemical and Biomedical Engineering Faculty Publications

Age-related hearing loss (ARHL) -presbycusis - is the most prevalent neurodegenerative disease and number one communication disorder of our aged population; and affects hundreds of millions of people worldwide. Its prevalence is close to that of cardiovascular disease and arthritis, and can be a precursor to dementia. The auditory perceptual dysfunction is well understood, but knowledge of the biological bases of ARHL is still somewhat lacking. Surprisingly, there are no FDA-approved drugs for treatment. Based on our previous studies of human subjects, where we discovered relations between serum aldosterone levels and the severity of ARHL, we treated middle age mice with ...


Silicone Elastomer-Based Combinatorial Biomaterial Gradients For High Throughput Screening Of Cell-Substrate Interactions, Greeshma Mohan Jan 2015

Silicone Elastomer-Based Combinatorial Biomaterial Gradients For High Throughput Screening Of Cell-Substrate Interactions, Greeshma Mohan

Graduate Theses and Dissertations

Biomaterials have evolved over the years from the passive role of mere biocompatibility to an increasingly active role of presenting instructive cues to elicit precise responses at the molecular and cellular levels. Various characteristics common to synthetic biomaterials in vitro and extracellular matrices in vivo, such as immobilized functional or peptide groups, mechanical stiffness, bulk physical properties and topographical features, are key players that regulate cell response. The dynamics in the cell microenvironment and at the cell adhesive interface trigger a web of cell-material and cell-cell information exchanges that have a profound impact in directing the ultimate cell fate decision ...


Fabrication Of Tissue Precursors Induced By Shape-Changing Hydrogels, Olukemi O. Akintewe Jan 2015

Fabrication Of Tissue Precursors Induced By Shape-Changing Hydrogels, Olukemi O. Akintewe

Graduate Theses and Dissertations

Scaffold based tissue reconstruction inherently limits regenerative capacity due to inflammatory response and limited cell migration. In contrast, scaffold-free methods promise formation of functional tissues with both reduced adverse host reactions and enhanced integration. Cell-sheet engineering is a well-known bottom-up tissue engineering approach that allows the release of intact cell sheet from a temperature responsive polymer such as poly-N-isopropylacrylamide (pNIPAAm). pNIPAAm is an ideal template for culturing cell sheets because it undergoes a sharp volume-phase transition owing to the hydrophilic and hydrophobic interaction around its lower critical solution temperature (LCST) of 32°C, a temperature close to physiological temperature. Compared ...


Structured Materials For Catalytic And Sensing Applications, Selma Hokenek Jan 2013

Structured Materials For Catalytic And Sensing Applications, Selma Hokenek

Graduate Theses and Dissertations

The optical and chemical properties of the materials used in catalytic and sensing applications directly determine the characteristics of the resultant catalyst or sensor. It is well known that a catalyst needs to have high activity, selectivity, and stability to be viable in an industrial setting. The hydrogenation activity of palladium catalysts is known to be excellent, but the industrial applications are limited by the cost of obtaining catalyst in amounts large enough to make their use economical. As a result, alloying palladium with a cheaper, more widely available metal while maintaining the high catalytic activity seen in monometallic catalysts ...


Shape-Shifting Surfaces For Rapid Release And Direct Stamping Of Organized Micro-Tissues, Samuel James Dupont Jan 2012

Shape-Shifting Surfaces For Rapid Release And Direct Stamping Of Organized Micro-Tissues, Samuel James Dupont

Graduate Theses and Dissertations

The primary aim of the research in this study is to develop a robust and simple platform for the in vitro organization of cells on surfaces which facilitate rapid cell release and allows for the direct stamping of highly organized micro-tissues. Current approaches towards this goal have been very successful but are lengthy and subject cells to harsh conditions for extended periods of time raising questions regarding cell health and maintenance of physiological state. To address these concerns a platform was developed to allow for rapid cell release by utilizing a release mechanism different from previous work.

Micron-scale structures comprised ...


The Conversion Of Low-Grade Heat Into Power Using Supercritical Rankine Cycles, Huijuan Chen Nov 2010

The Conversion Of Low-Grade Heat Into Power Using Supercritical Rankine Cycles, Huijuan Chen

Graduate Theses and Dissertations

Low-grade heat sources, here defined as below 300 ºC, are abundantly available as industrial waste heat, solar thermal, and geothermal, to name a few. However, they are under-exploited for conversion to power because of the low efficiency of conversion. The utilization of low-grade heat is advantageous for many reasons. Technologies that allow the efficient conversion of low-grade heat into mechanical or electrical power are very important to develop.

This work investigates the potential of supercritical Rankine cycles in the conversion of low-grade heat into power. The performance of supercritical Rankine cycles is studied using ChemCAD linked with customized excel macros ...


Plasma Mediated Molecular Delivery, Richard J. Connolly Oct 2010

Plasma Mediated Molecular Delivery, Richard J. Connolly

Graduate Theses and Dissertations

Non-viral delivery of plasmid DNA has traditionally relied upon physical forces applied directly to target tissues. These physical methods typically involve contact between an applicator and the target tissue and often cause transient patient discomfort. To overcome the contact-dependent limitations of such delivery methodologies, an atmospheric direct current plasma source was developed to deposit ionized gas molecules onto localized treatment sites. The deposition of charged species onto a treatment site can lead to the establishment of an electric field with strengths similar to those used for traditional electroporation. In vitro experiments proved that this technology could transiently permeabilize cell membranes ...


The Virtual Hip: An Anatomically Accurate Finite Element Model Based On The Visible Human Dataset, Jonathan M. Ford Oct 2010

The Virtual Hip: An Anatomically Accurate Finite Element Model Based On The Visible Human Dataset, Jonathan M. Ford

Graduate Theses and Dissertations

The purpose of this study is to determine if element decimation of a 3-D anatomical model affects the results of Finite Element Analysis (FEA). FEA has been increasingly applied to the biological and medical sciences. In order for an anatomical model to successfully run in FEA, the 3-D model’s complex geometry must be simplified, resulting in a loss of anatomical detail. The process of decimation reduces the number of elements within the structure and creates a simpler approximation of the model. Using the National Library of Medicine’s Visible Human Male dataset, a virtual 3-D representation of several structures ...


Investigation Of Buildup Dose For Therapeutic Intensity Modulated Photon Beams In Radiation Therapy, Khosrow Javedan Jul 2010

Investigation Of Buildup Dose For Therapeutic Intensity Modulated Photon Beams In Radiation Therapy, Khosrow Javedan

Graduate Theses and Dissertations

Buildup dose of Mega Voltage (MV) photon beams can be a limiting factor in intensitymodulated radiation therapy (IMRT) treatments. Excessive doses can cause patient discomfort and treatment interruptions, while underdosing may lead to local failure.

Many factors which contribute to buildup dose, including the photon beam energy spectrum, scattered or contaminant radiation and their angular distribution, are not modeled well in commercial treatment planning systems. The accurate Monte Carlo method was employed in the studies to estimate the doses.

Buildup dose of 6MV photon beams was investigated for three fundamentally different IMRT modalities: between Helical TomoTherapy and traditional opposed tangential ...


Synthesis, Characterization, And Self-Assembly Of Gold Nanorods And Nanoprisms, Kristina L. Tran Jun 2010

Synthesis, Characterization, And Self-Assembly Of Gold Nanorods And Nanoprisms, Kristina L. Tran

Graduate Theses and Dissertations

The unique properties of gold nanoparticles make them excellent candidates for applications in electronics, sensing, imaging, and photothermal therapy. Though abundant literature exists for isotropic gold nanoparticles, work on nanoparticles of different shapes has been gaining interest recently. Anisotropic gold nanoparticles, such as nanorods and nanoprisms, have tunable optical properties in the visible and near-infrared regions. Through synthesis and surface modification, the production of various shapes of these gold nanoparticles can be controlled to meet different applications.

Two different types of gold nanorods were used in this thesis. The first type was stabilized with cetyltrimethylammonium bromide (CTAB) and had aspect ...


Effects Of Monoclonal Anti-Abeta Antibodies On The Amyloid Beta Peptide Fibrillogenesis And Their Involvement In The Clearance Of Alzheimer's Disease Plaques, Jeffy Pilar Jimenez May 2010

Effects Of Monoclonal Anti-Abeta Antibodies On The Amyloid Beta Peptide Fibrillogenesis And Their Involvement In The Clearance Of Alzheimer's Disease Plaques, Jeffy Pilar Jimenez

Graduate Theses and Dissertations

Alzheimer’s disease (AD) is the most common cause of senile dementia worldwide. AD is a neurodegenerative disorder characterized by the loss of memory and language skill, collapse of the cognitive function, and distortion of social behavior. As of today, the onset mechanisms of AD and cure are unknown; however, three hallmarks are commonly encountered: extra and intracellular accumulation of amyloid beta (A!) peptide plaques, formation of intracellular neurofibrillary tangles, and inevitable neuronal death. Hypothetically, a possible scenario provoking or involved in the onset of AD is a cascade effect that starts with an imbalance in the production and clearance ...


Pegylation Of Niosomes, John A. Elliott Nov 2009

Pegylation Of Niosomes, John A. Elliott

Graduate Theses and Dissertations

The research presented in this dissertation describes the creation and characterization of a novel antibody-vesicle conjugate modified with polyethylene glycol (PEG) that possesses enhanced binding to and uptake by inflammation-activated endothelial cells with improved storage stability and longer shelf-life and potential reduction in immunogenic potential compared to previous designs.

Targeted drug delivery provides an effective means of delivering therapeutic concentrations of a drug to the site or organ of action. The drug is delivered using a niosome, a vesicle with an aqueous core and a bilayer membrane composed of non-ionic surfactants and cholesterol. Antibodies that recognize specific cell antigens are ...