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Articles 7711 - 7740 of 11471

Full-Text Articles in Engineering

Scratch Damage Evolution On Metals In Total Joint Replacements, Caleb Eljach Dec 2013

Scratch Damage Evolution On Metals In Total Joint Replacements, Caleb Eljach

All Theses

The goal of total joint replacement (TJR) is to replace nonfunctioning joint components and relieve pain, improve quality of life, and to improve joint function. Although TJR is a successful procedure, more than 54,000 knee revisions occur each year due to factors, such as wear, loosening, infection, fracture, instability, and patient related factors (Ranawat, 2010). TJRs consist of components typically composed of polyethylene and a metallic counterface (Navarro, 2008). The sliding contact that occurs between the metal and polyethylene components has been well studied and is shown to produce both surface damage and wear of the implant components (Barbour, 1997; …

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Functional Stroke Recovery Through Tissue Engineered Niche Neural Constructs, Natasha Topoluk Dec 2013

Functional Stroke Recovery Through Tissue Engineered Niche Neural Constructs, Natasha Topoluk

All Theses

According to the Centers for Disease Control and Prevention, stroke is statistically responsible for 1 in every 19 deaths of American citizens.5 Stroke is the leading cause of permanent disability due to the fact that it compromises both cellular and tissue components of the brain, leading to the formation of a physical void within the tissue. Current research approaches address the cellular component by injecting stem cells into this void; however, extremely low cell engraftment, high injected cell death, and overall no matrix regeneration are observed. Additionally, these stem cells do not remain committed to a neural lineage. We propose …

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The Effects Of Different Size Gold Nanoparticles On Mechanical Properties Of Vascular Smooth Muscle Cells Under Mechanical Stretching, Tri Kieu Dec 2013

The Effects Of Different Size Gold Nanoparticles On Mechanical Properties Of Vascular Smooth Muscle Cells Under Mechanical Stretching, Tri Kieu

All Theses

The field of nanotechnology research has seen a large growth in the past few decades due to the great potential of novel nano-size material for useful applications such as drug delivery and medical imaging. Also, they are a promising platform for the detection of terrible diseases such as cancer and atherosclerosis. Although these materials hold great promise, there is very limited understanding about the biological effects of these nanoparticles on normal healthy cells, such as vascular smooth muscle cells (VSMCs). The VSMCs are unique cells due to the two distinct phenotype characteristics it can express: a contractile and a synthetic …

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Vascular Nanomedicine: Site Specific Delivery Of Elastin Stabilizing Therapeutics To Damaged Arteries, Aditi Sinha Dec 2013

Vascular Nanomedicine: Site Specific Delivery Of Elastin Stabilizing Therapeutics To Damaged Arteries, Aditi Sinha

All Dissertations

Elastin, a structural protein in the extra-cellular matrix, plays a critical role in the normal functioning of blood vessels. Apart from performing its primary function of providing resilience to arteries, it also plays major role in regulating cell-cell and cell-matrix interactions, response to injury, and morphogenesis. Medial arterial calcification (MAC) and abdominal aortic aneurysm (AAA) are two diseases where the structural and functional integrity of elastin is severely compromised. Although the clinical presentation of MAC and AAA differ, they have one common underlying causative mechanism--pathological degradation of elastin. Hence prevention of elastin degradation in the early stages of MAC and …

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Biological Scaffolds For Peripheral Vascular Surgery, George Fercana Dec 2013

Biological Scaffolds For Peripheral Vascular Surgery, George Fercana

All Dissertations

The gold standards for small diameter peripheral vascular graft replacement are autologous arteries or veins; however, one-third of patients lack such vessels due to previous vessel harvesting or advanced vascular disease. A promising approach for patients in this category is tissue engineering with off-the-shelf biological vascular grafts. Three small diameter acellular scaffolds were developed and evaluated as vascular grafts. Porcine renal arteries (2-3 mm diameter, 20 mm length) were decellularized by immersion and stabilized with penta-galloyl glucose (PGG) with and without subsequent heparinization via carbodiimide chemistry. Bovine mammary (4-6 mm ID, 250 mm length) and femoral arteries (6-8 mm ID, …

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Action Potential Simulation Of The Hirudo Medicinalis's Retzius Cell In Matlab, Zechari Ryan Tempesta Dec 2013

Action Potential Simulation Of The Hirudo Medicinalis's Retzius Cell In Matlab, Zechari Ryan Tempesta

Master's Theses

Modification of Hodgkin and Huxley’s experimentally derived set of nonlinear differential equations was implemented to accurately simulate the action potential of the Hirudo Medicinalis’s Retzius cell in MATLAB under analogous conditions to those found in the Retzius cell environment. The voltage-gated sodium and potassium channel responses to changes in membrane potential, as experimentally determined by Hodgkin and Huxley, were manipulated to suit simulation parameters established by electrophysiological Retzius cell recordings. Application of this methodology permitted additional accurate simulation of the Hirudo Medicinalis’s P cell under analogous conditions to those found in the P cell environment. Further refinement of this technique …

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Formulation Development Of A Polymer-Drug Matrix With A Controlled Release Profile For The Treatment Of Glaucoma, Eric W. Tsoi Dec 2013

Formulation Development Of A Polymer-Drug Matrix With A Controlled Release Profile For The Treatment Of Glaucoma, Eric W. Tsoi

Master's Theses

Glaucoma is the leading cause of blindness in the United States accounting for 9-12% of all cases of blindness. Currently, the front line treatment for glaucoma are prostaglandins that may have to be taken up to several times a day. Even with proper treatment, roughly 11% of the patients using the treatment are non-compliant and lose their vision. In this project, ForSight Laboratories has developed a pharmaceutical drug delivering implant with the capability of sustaining long-term release of a prostaglandin as a new way to treat the condition. This project reports the product development of a polymer drug matrix with …

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Mechanical Properties Of Bone Due To Sost Expression: Nanoindentation Assessment Of Murine Femurs, Amir Rafie Dec 2013

Mechanical Properties Of Bone Due To Sost Expression: Nanoindentation Assessment Of Murine Femurs, Amir Rafie

Master's Theses

In the human genome, the SOST gene codes for a protein sclerostin. Sclerostin is an osteocyte-expressed negative regulator of bone formation. When the SOST gene is not coded, bone formation is reduced in individuals during skeletal maturation. This study utilizes nanoindentation methods to test for the mechanical properties of bones that both express and do not express the SOST gene. 100 transgenic murine femurs were obtained from Lawrence Livermore Labs in the form of 6 and 8 month SOST transgenic mice, 6 and 12 month SOST knockout mice, and wild type control littermates for each of the 4 age groups. …

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Near-Infrared Surface-Enhanced Fluorescence Using Silver Nanoparticles In Solution, Michael D. Furtaw Dec 2013

Near-Infrared Surface-Enhanced Fluorescence Using Silver Nanoparticles In Solution, Michael D. Furtaw

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fluorescence spectroscopy is a widely used detection technology in many research and clinical assays. Further improvement to assay sensitivity may enable earlier diagnosis of disease, novel biomarker discovery, and ultimately, improved outcomes of clinical care along with reduction in costs. Near-infrared, surface-enhanced fluorescence (NIR-SEF) is a promising approach to improve assay sensitivity via simultaneous increase in signal with a reduction in background. This dissertation describes research conducted with the overall goal to determine the extent to which fluorescence in solution may be enhanced by altering specific variables involved in the formation of plasmonactive nanostructures of dye-labeled protein and silver nanoparticles …

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Identification Of Novel Genes Regulating Elastic Fiber Formation Through Expression Profiling Analysis Of Elastogenic Models, Erin Sproul Dec 2013

Identification Of Novel Genes Regulating Elastic Fiber Formation Through Expression Profiling Analysis Of Elastogenic Models, Erin Sproul

All Dissertations

Background: Particularly important to the mechanical performance of native arterial blood vessels is elastin, an extracellular matrix (ECM) protein deposited by VSMCs in the form of elastic fibers, arranged in concentric lamellae in the media of the vessel wall. In addition to serving as major structural elements of arterial walls, providing extensibility and elastic recoil, elastic fibers also influence vascular cell behaviors. For these reasons tissue engineers are attempting to exploit elastic fiber biology to enhance vascular graft design and patency. Therefore, developing a greater understanding of the molecular mechanisms of elastogenesis may offer opportunities to control elastogenesis in tissue …

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Engineering Beta-Cell Spheroids For Type 1 Diabetes Treatment, Xiaoyan Liu Dec 2013

Engineering Beta-Cell Spheroids For Type 1 Diabetes Treatment, Xiaoyan Liu

All Dissertations

Diabetes mellitus, the third most common disease in the world, is a chronic metabolic disorder caused by a failure of insulin production and/or an inability to respond to insulin. Specifically, type 1 diabetes is a disorder characterized by targeted autoimmune-directed destruction of a patient's beta-cell population within the pancreatic islets of Langerhans. The current primary treatment for type 1 diabetes is daily multiple insulin injections. However, this treatment cannot provide sustained physiological release, and the insulin amount is not finely tuned to glycemia. Pancreatic transplants or islet transplants would be the preferred treatment method but the lack of donor tissue …

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Characterization And Feasibility Of A Portable Oxygen Concentrator For Use With A Mass Casualty Ventilator, Paul Robert Williams Dec 2013

Characterization And Feasibility Of A Portable Oxygen Concentrator For Use With A Mass Casualty Ventilator, Paul Robert Williams

Boise State University Theses and Dissertations

The American Association for Respiratory Care has reported a need to stockpile 5,000-10,000 mass casualty ventilators with supplemental oxygen in preparation for pandemic emergencies (1). The American Medical Association specifies oxygen concentrators supply oxygen at 5 liters per minute at ≥90% purity (2). However, these design specifications may not be the most efficient use of system resources in portable oxygen concentrators using pressure swing adsorption. A testbed was developed to investigate the system performance of an oxygen concentrator while altering the system inlet and outlet pressures and flow rates. This investigation demonstrates that a more efficient portable oxygen concentrator, which …

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Dopaminergic Modulation Of Memory And Affective Processing In Parkinson Depression, Lee X. Blonder, John T. Slevin, Richard J. Kryscio, Catherine A. Martin, Anders H. Andersen, Charles D Smith, Frederick A. Schmitt Nov 2013

Dopaminergic Modulation Of Memory And Affective Processing In Parkinson Depression, Lee X. Blonder, John T. Slevin, Richard J. Kryscio, Catherine A. Martin, Anders H. Andersen, Charles D Smith, Frederick A. Schmitt

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Depression is common in Parkinson's disease and is associated with cognitive impairment. Dopaminergic medications are effective in treating the motor symptoms of Parkinson's disease; however, little is known regarding the effects of dopaminergic pharmacotherapy on cognitive function in depressed Parkinson patients. This study examines the neuropsychological effects of dopaminergic pharmacotherapy in Parkinsonian depression. We compared cognitive function in depressed and non-depressed Parkinson patients at two time-points: following overnight withdrawal and after the usual morning regimen of dopaminergic medications. A total of 28 non-demented, right-handed patients with mild to moderate idiopathic Parkinson's disease participated. Ten of these patients were depressed according …

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Diffuse Correlation Spectroscopy (Dcs) For Assessment Of Tissue Blood Flow In Skeletal Muscle: Recent Progress, Yu Shang, Katelyn Gurley, Guoqiang Yu Nov 2013

Diffuse Correlation Spectroscopy (Dcs) For Assessment Of Tissue Blood Flow In Skeletal Muscle: Recent Progress, Yu Shang, Katelyn Gurley, Guoqiang Yu

Biomedical Engineering Faculty Publications

Near-infrared diffuse correlation spectroscopy (DCS) is an emerging technology for monitoring blood flow in various tissues. This article reviews the recent progress of DCS for the assessment of skeletal muscle blood flow, including the developments in technology allowing use during dynamic exercise and muscular electrical stimulation, the utilization for diagnosis of muscle vascular diseases, and the applications for evaluating treatment effects. The limitations of current DCS studies and future perspective are finally discussed.

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Skeletal Muscle Contraction Simulation: A Comparison In Modeling, Jonathan M. Ford Nov 2013

Skeletal Muscle Contraction Simulation: A Comparison In Modeling, Jonathan M. Ford

USF Tampa Graduate Theses and Dissertations

Computer generated three-dimensional (3-D) models are being used at increasing rates in the fields of entertainment, education, research, and engineering. One of the aspects of interest includes the behavior and function of the musculoskeletal system. One such tool used by engineers is the finite element method (FEM) to simulate the physics behind muscle mechanics. There are several ways to represent 3-D muscle geometry, namely a bulk, a central line of action and a spline model. The purpose of this study is to exmine how these three representations affect the overall outcome of muscle movement. This is examined in a series …

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Spectral Analysis Of Nonstationary Heart Rate Of Neonates Receiving Therapeutic Hypothermia Treatment, Tareq Al-Shargabi Nov 2013

Spectral Analysis Of Nonstationary Heart Rate Of Neonates Receiving Therapeutic Hypothermia Treatment, Tareq Al-Shargabi

Theses and Dissertations

We studied Heart Rate Variability (HRV) evolution during therapeutic hypothermia in newborns with hypoxic ischemic encephalopathy (HIE) using spectral analysis. We hypothesized that HRV measures are predictive of neurological outcome in babies with HIE. Non-stationarity in the data causes inaccurate quantification of the spectral power. A modification was proposed to power spectral analysis approach to mitigate the effect of non-stationarity. The modified and the standard approaches were applied to cardiac beat-to-beat intervals of newborns receiving hypothermia treatment. The performance of the approaches in distinguishing the RRi dynamics of two groups of newborns was assessed using area under the receiver operating …

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Visuo-Proprioceptive Interactions During Adaptation Of The Human Reach, Timothy Judkins, Robert A. Scheidt Nov 2013

Visuo-Proprioceptive Interactions During Adaptation Of The Human Reach, Timothy Judkins, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We examined whether visual and proprioceptive estimates of transient (mid-reach) target capture errors contribute to motor adaptation according to the probabilistic rules of information integration used for perception. Healthy adult humans grasped and moved a robotic handle between targets in the horizontal plane while the robot generated spring-like loads that varied unpredictably from trial-to-trial. For some trials, a visual cursor faithfully tracked hand motion. In others, the handle's position was locked and subjects viewed motion of a point-mass cursor driven by hand forces. In yet other trials, cursor feedback was dissociated from hand motion or altogether eliminated. We used time- …

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Simulation Of Vertical Axis Wind Turbines With Variable Pitch Foils, L. Damon Woods, John F. Gardner, Kurt S. Myers Nov 2013

Simulation Of Vertical Axis Wind Turbines With Variable Pitch Foils, L. Damon Woods, John F. Gardner, Kurt S. Myers

Mechanical and Biomedical Engineering Faculty Publications and Presentations

A dynamic computer model of a turbine was developed in MATLAB in order to study the behavior of vertical axis wind turbines (VAWTs) with variable pitch (articulating) foils. The simulation results corroborated the findings of several empirical studies on VAWTs. The model was used to analyze theories of pitch articulation and to inform the discussion on turbine design. Simulations of various models showed that pitch articulation allowed Darrieus-style vertical axis wind turbines to start from rest. Once in motion, the rotor was found to accelerate rapidly to very high rotational velocities. The simulations revealed a plateau region of high efficiency …

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Brain-Related Chronic Pain Disorder Treatment Method And Apparatus, Jeffrey Hargrove, Robert M. Ford, Buckley D. Beranek Nov 2013

Brain-Related Chronic Pain Disorder Treatment Method And Apparatus, Jeffrey Hargrove, Robert M. Ford, Buckley D. Beranek

Mechanical Engineering Patents

A method for treating brain-related chronic pain disorders in human subjects includes assessing the brain function of a subject suffering from chronic pain, diagnosing a chronic pain-related abnormal brain condition, and mitigating the abnormal brain activity by applying an electrical stimulation signal to tissues corresponding to at least one area of abnormal brain activity.

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Relating Ph And Ion Release From Ga2o3-Na 2o-Cao-Zno-Sio2 Bioactive Glasses, T. J. Keenan, A. W. Wren, A. Coughlan, Mark R. Towler, M. M. Hall Nov 2013

Relating Ph And Ion Release From Ga2o3-Na 2o-Cao-Zno-Sio2 Bioactive Glasses, T. J. Keenan, A. W. Wren, A. Coughlan, Mark R. Towler, M. M. Hall

Chemical and Biochemical Engineering Faculty Research & Creative Works

Three glasses were designed for this study, including one Ga-free glass (Control), and two Ga-containing glasses (TGa-1, TGa-2). In the Ga-containing glasses, Ga2O3 is included at the expense of ZnO. This study focuses on the relation between pH and ion concentration present in solution in which these bioactive glasses have been submerged for periods of 1, 7, and 14 days. © 2013 IEEE.

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Gallium Containing Glass Polyalkenoate Bone Cements: Ion Release And E. Coli Inhibition, L. Placek, A. W. Wren, A. Coughlan, Mark R. Towler Nov 2013

Gallium Containing Glass Polyalkenoate Bone Cements: Ion Release And E. Coli Inhibition, L. Placek, A. W. Wren, A. Coughlan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Glass Polyalkenoate Cement (GPC) series (LCon., LGa-1 and LGa-2) containing gallium (Ga) and a 50 wt% addition of E11 polyacrylic acid (PAA), previously developed, was evaluated for ion release, specifically Si, Ca, Zn and Ga, and E. coli inhibition. The maximum inhibition was observed in the t = 0 samples and was 0.35 mm for LCon. and 0.65 mm for LGa-1 and LGa-2. © 2013 IEEE.

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Biocompatibility Of Cao-Na2o-Sio2/Tio2 Glass Ceramic Scaffolds For Orthopaedic Applications, A. W. Wren, A. Coughlan, K. E. Smale, S. T. Misture, B. P. Mahon, O. M. Clarkin, Mark R. Towler Nov 2013

Biocompatibility Of Cao-Na2o-Sio2/Tio2 Glass Ceramic Scaffolds For Orthopaedic Applications, A. W. Wren, A. Coughlan, K. E. Smale, S. T. Misture, B. P. Mahon, O. M. Clarkin, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

This work aims to determine the effect of substituting TiO2 for SiO2 in a 0.62SiO2-Na2O-0.24CaO based glass-ceramic scaffold. High temperature X-ray Diffraction (HT-XRD) was used to determine the sintering temperature (700oC). Both optical microscopy and x-ray micotomography was used to determine the average pore size (540-680ìm) of each scaffold. Cytocompatibility of each scaffold was conducted using murine mesenchymal stem cells. © 2013 IEEE.

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An Investigation Into The Structure And Properties Of Cao-Zno-Sio 2-Tio2-Na2o Bioactive Glass/Hydroxyapatite Composite, Chokchai Yatongchai, Mark R. Towler, Anthony W. Wren Nov 2013

An Investigation Into The Structure And Properties Of Cao-Zno-Sio 2-Tio2-Na2o Bioactive Glass/Hydroxyapatite Composite, Chokchai Yatongchai, Mark R. Towler, Anthony W. Wren

Chemical and Biochemical Engineering Faculty Research & Creative Works

Effect of the addition of CaO-ZnO-SiO2-TiO2-Na2O glass as a reinforcing phase on properties of hydroxyapatite/glass composites was investigated. The addition of the glass caused the decomposition of HA phase to tricalcium phosphate, inhibiting densification in the HA/glass composites. However, depending on the glass concentration, some of the glass can act as a sintering aid enhancing the densification in the composites. © 2013 IEEE.

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Physiological Fluid Specific Agglomeration Patterns Diminish Gold Nanorod Photothermal Characteristics, Kristen K. Comfort, Jared W. Speltz, Bradley M. Stacy, Larry R. Dosser, Saber M. Hussain Nov 2013

Physiological Fluid Specific Agglomeration Patterns Diminish Gold Nanorod Photothermal Characteristics, Kristen K. Comfort, Jared W. Speltz, Bradley M. Stacy, Larry R. Dosser, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

Investigations into the use of gold nanorods (Au-NRs) for biological applications are growing exponentially due to their distinctive physicochemical properties, which make them advantageous over other nanomaterials. Au-NRs are particularly renowned for their plasmonic characteristics, which generate a robust photothermal response when stimulated with light at a wavelength matching their surface plasmon resonance. Numerous reports have explored this nanophotonic phenomenon for temperature driven therapies; however, to date there is a significant knowledge gap pertaining to the kinetic heating profile of Au-NRs within a controlled physiological setting. In the present study, the impact of environmental composition on Au-NR behavior and degree …

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Development Of A Computational Approach To Assess Hip Fracture And Repair: Considerations Of Intersubject And Surgical Alignment Variability, Azhar Ali Nov 2013

Development Of A Computational Approach To Assess Hip Fracture And Repair: Considerations Of Intersubject And Surgical Alignment Variability, Azhar Ali

Electronic Theses and Dissertations

Hip fracture remains a major public health concern due to the significant number of occurrences and mortality rates. Intertrochanteric fractures are the most common type of fracture and are typically caused by a fall. Intramedullary osteosynthesis is a common surgical practice to repair intertrochanteric fractures, but revisions are often required. The work presented in this thesis aims to improve the realism and fidelity of computational models of hip fracture, which can be an effective alternative to costly and labor-intensive clinical in-vivo and experimental in-vitro testing. Intersubject variability is inherently present in anatomy and material relations. Statistical shape and intensity models …

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Biologically Enhanced Cathode Design For Improved Capacity And Cycle Life For Lithium-Oxygen Batteries, Dahyun Oh, Jifa Qi, Yi-Chun Lu, Yong Zhang, Yang Shao-Horn, Angela Belcher Nov 2013

Biologically Enhanced Cathode Design For Improved Capacity And Cycle Life For Lithium-Oxygen Batteries, Dahyun Oh, Jifa Qi, Yi-Chun Lu, Yong Zhang, Yang Shao-Horn, Angela Belcher

Faculty Publications

Lithium-oxygen batteries have a great potential to enhance the gravimetric energy density of fully packaged batteries by two to three times that of lithium ion cells. Recent studies have focused on finding stable electrolytes to address poor cycling capability and improve practical limitations of current lithium-oxygen batteries. In this study, the catalyst electrode, where discharge products are deposited and decomposed, was investigated as it has a critical role in the operation of rechargeable lithium-oxygen batteries. Here we report the electrode design principle to improve specific capacity and cycling performance of lithium-oxygen batteries by utilizing high-efficiency nanocatalysts assembled by M13 virus …

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Advances In Homology Directed Genetic Engineering Of Human Pluripotent And Adult Stem Cells, Kalpith Ramamoorthi, Donald Curtis, Prashanth Asuri Oct 2013

Advances In Homology Directed Genetic Engineering Of Human Pluripotent And Adult Stem Cells, Kalpith Ramamoorthi, Donald Curtis, Prashanth Asuri

Bioengineering

The ability to introduce precise genomic modifications in human cells has profound implications for both basic and applied research in stem cells, ranging from identification of genes regulating stem cell self-renewal and multilineage differentiation to therapeutic gene correction and creation of in vitro models of human diseases. However, the overall efficiency of this process is challenged by several factors including inefficient gene delivery into stem cells and low rates of homology directed site-specific targeting. Recent studies report the development of novel techniques to improve gene targeting efficiencies in human stem cells; these methods include molecular engineering of viral vectors o …

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Engineered Nanotopography On Electrospun Plla Microfibers Modifies Raw 264.7 Cell Response, Nicholas J. Schaub, Tara Britton, Rupak Rajachar, Ryan J. Gilbert Oct 2013

Engineered Nanotopography On Electrospun Plla Microfibers Modifies Raw 264.7 Cell Response, Nicholas J. Schaub, Tara Britton, Rupak Rajachar, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

In this study, we created a new method of electrospinning capable of controlling the surface structure of individual fibers (fiber nano topography). The nano topographical features were created by a phase separation in the fibers as they formed. To control the phase separation, a nonsolvent (a chemical insoluble with the polymer) was added to an electrospinning solution containing poly-l-lactic acid (PLLA) and chloroform. The nano topography of electro spun fibers in the PLLA/chloroform solution was smooth. However, adding a small weight (< 2% of total solution) of a single nonsolvent (water, ethanol, or dimethyl sulfoxide) generated nanoscale depressions on the surface of the fibers unique to the nonsolvent added. Additionally, nanoscale depressions on electro spun fibers were observed to change with dimethyl sulfoxide (DMSO) concentration in the PLLA/chloroform solution. A nonlinear relationship was found between the concentration of DMSO and the number and size of nano topographical features. The surface depressions did not alter the hydrophobicity of the scaffold or degradation of the scaffold over a two-day period. To determine if fiber nano topography altered cell behavior, macrophages (RAW 264.7 cells) were cultured on fibers with a smooth nano topography or fibers with nanoscale depressions. RAW 264.7 cells spread less on fibers with nanoscale depressions than fibers with a smooth topography (p < 0.05), but there were no differences between groups with regard to cell metabolism or the number of adherent cells. The results of this study demonstrate the necessity to consider the nano topography of individual fibers as these features may affect cellular behavior. More importantly, we demonstrate a versatile method of controlling electro spun fiber nano topography. © 2013 American Chemical Society.

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Mammalian Cells Preferentially Internalize Hydrogel Nanodiscs Over Nanorods And Use Shape-Specific Uptake Mechanisms, Rachit Agarwal, Vikramjit Singh, Patrick Jurney, Li Shi, S. Sreenivasan, Krishnendu Roy Oct 2013

Mammalian Cells Preferentially Internalize Hydrogel Nanodiscs Over Nanorods And Use Shape-Specific Uptake Mechanisms, Rachit Agarwal, Vikramjit Singh, Patrick Jurney, Li Shi, S. Sreenivasan, Krishnendu Roy

Faculty Publications

Size, surface charge, and material compositions are known to influence cell uptake of nanoparticles. However, the effect of particle geometry, i.e., the interplay between nanoscale shape and size, is less understood. Here we show that when shape is decoupled from volume, charge, and material composition, under typical in vitro conditions, mammalian epithelial and immune cells preferentially internalize disc-shaped, negatively charged hydrophilic nanoparticles of high aspect ratios compared with nanorods and lower aspect-ratio nanodiscs. Endothelial cells also prefer nanodiscs, however those of intermediate aspect ratio. Interestingly, unlike nanospheres, larger-sized hydrogel nanodiscs and nanorods are internalized more efficiently than their smallest counterparts. …

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Synthesis And Characterization Of Nucleic Acid-Functionalized Nanomaterials, Brianna S. Carroll, Jong Hyun Choi Oct 2013

Synthesis And Characterization Of Nucleic Acid-Functionalized Nanomaterials, Brianna S. Carroll, Jong Hyun Choi

The Summer Undergraduate Research Fellowship (SURF) Symposium

Motor proteins such as kinesin move along microtubules in order to transport cellular cargos throughout the cell by obtaining energy from RNA hydrolysis which allows the cell to complete the tasks needed to stay alive. In this work, we developed synthetic molecular motors using DNA enzymes (DNAzyme) and fluorescent nanomaterials which mimic the functions and structures of motor proteins. A DNAzyme-capped CdS nanoparticle and a RNA-functionalized single-walled carbon nanotube (SWCNT) were used as a walker and a track in the motor platform, respectively. As a walking mechanism, the DNAzyme cleaved the RNA substrates in the presence of metal cations. The …

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