Nanoindentation Techniques For The Evaluation Of Silicon Nitride Thin Films,
2016
California Polytechnic State University, San Luis Obispo
Nanoindentation Techniques For The Evaluation Of Silicon Nitride Thin Films, Weston T. Mangin
Master's Theses
Silicon nitride thin films are of interest in the biomedical engineering field due to their biocompatibility and favorable tribological properties. Evaluation and understanding of the properties of these films under diverse loading and failure conditions is a necessary prerequisite to their use in biomedical devices. Three wafers of silicon nitride-coated silicon were obtained from Lawrence Livermore National Laboratory and used to create 96 samples. Samples were subjected to nanoindentation testing to evaluate the mechanical properties of the film. Samples were subjected to nanoimpact testing to compare the damage resistance of the film to separate nanoimpact types. Samples were subjected to …
Biopolymer Electrospun Nanofiber Mats To Inactivate And Remove Bacteria,
2016
University of Massachusetts Amherst
Biopolymer Electrospun Nanofiber Mats To Inactivate And Remove Bacteria, Katrina Ann Rieger
Doctoral Dissertations
The persistence of antibiotic resistance in bacterial pathogens remains a primary concern for immunocompromised and critically-ill hospital patients. Hospital associated infections can be deadly and reduce the successes of medical advancements, such as, cancer therapies and medical implants. Thus, it is imperative to develop materials that can (i) deliver new antibiotics with accuracy, as well as (ii) uptake pathogenic microbes. In this work, we will demonstrate that electrospun nanofiber mats offer a promising platform for both of these objectives because of their high surface-to-volume ratio, interconnected high porosity, gas permeability, and ability to contour to virtually any surface. To provide …
Extracellular Matrix Control Of Breast Cancer Metastasis And Dormancy,
2016
University of Massachusetts Amherst
Extracellular Matrix Control Of Breast Cancer Metastasis And Dormancy, Lauren Barney
Doctoral Dissertations
To metastasize, a cell must travel through circulation to a secondary tissue, and this process causes 90% of all cancer deaths. Although inefficient, metastasis is not random, and only capable seeds in hospitable soils are capable of outgrowing into detectable metastases. The overall hypothesis in this work is that the secondary tissue microenvironment, particularly the extracellular matrix (ECM), mediates metastasis. We posit that the ability of metastatic cells to survive dormancy, exit quiescence, and colonize a tissue depends upon the ability of the soil to sustain survival, and subsequently trigger outgrowth. We created a simple biomaterial platform with systematic control …
Use Of A Modified Greenscreen Tool To Conduct A Screening-Level Comparative Hazard Assessment Of Conventional Silver And Two Forms Of Nanosilver.,
2016
George Washington University
Use Of A Modified Greenscreen Tool To Conduct A Screening-Level Comparative Hazard Assessment Of Conventional Silver And Two Forms Of Nanosilver., Jennifer Sass, Lauren Heine, Nina Hwang
Environmental and Occupational Health Faculty Publications
BACKGROUND: Increased concern for potential health and environmental impacts of chemicals, including nanomaterials, in consumer products is driving demand for greater transparency regarding potential risks. Chemical hazard assessment is a powerful tool to inform product design, development and procurement and has been integrated into alternative assessment frameworks. The extent to which assessment methods originally designed for conventionally-sized materials can be used for nanomaterials, which have size-dependent physical and chemical properties, have not been well established. We contracted with a certified GreenScreen profiler to conduct three GreenScreen hazard assessments, for conventional silver and two forms of nanosilver. The contractor summarized publicly …
Lipid Coated Microbubbles And Low Intensity Pulsed Ultrasound Enhance Chondrogenesis Of Human Mesenchymal Stem Cells In 3d Printed Scaffolds,
2016
George Washington University
Lipid Coated Microbubbles And Low Intensity Pulsed Ultrasound Enhance Chondrogenesis Of Human Mesenchymal Stem Cells In 3d Printed Scaffolds, Mitra Aliabouzar, Lijie Grace Zhang, Kausik Sarkar
Medicine Faculty Publications
Lipid-coated microbubbles are used to enhance ultrasound imaging and drug delivery. Here we apply these microbubbles along with low intensity pulsed ultrasound (LIPUS) for the first time to enhance proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in a 3D printed poly-(ethylene glycol)-diacrylate (PEG-DA) hydrogel scaffold. The hMSC proliferation increased up to 40% after 5 days of culture in the presence of 0.5% (v/v) microbubbles and LIPUS in contrast to 18% with LIPUS alone. We systematically varied the acoustic excitation parameters—excitation intensity, frequency and duty cycle—to find 30 mW/cm2, 1.5 MHz and 20% duty cycle to be optimal …
Surface Engineering Of Titanium Alloy To Stimulate The Bone Regeneration,
2016
Tianjin University
Surface Engineering Of Titanium Alloy To Stimulate The Bone Regeneration, Yubin Meng, Zhenduo Cui, Zhaoyang Li, Xue Li, Jin Zhao, Xubo Yuan, Xianjin Yang
The 8th International Conference on Physical and Numerical Simulation of Materials Processing
No abstract provided.
Fluorescent Materials Design At Nanoscale For Biomedical Photonics In Near Infrared Window,
2016
Tokyo University of Science
Fluorescent Materials Design At Nanoscale For Biomedical Photonics In Near Infrared Window, Kohei Soga, Masao Kamimura
The 8th International Conference on Physical and Numerical Simulation of Materials Processing
No abstract provided.
Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein,
2016
Michigan Technological University
Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee
Department of Biomedical Engineering Publications
Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface …
Long-Term Biocompatibility, Imaging Appearance And Tissue Effects Associated With Delivery Of A Novel Radiopaque Embolization Bead For Image-Guided Therapy,
2016
George Washington University
Long-Term Biocompatibility, Imaging Appearance And Tissue Effects Associated With Delivery Of A Novel Radiopaque Embolization Bead For Image-Guided Therapy, Karun Sharma, Zainab Bascal, Hugh Kilpatrick, Koorosh Ashrafi, Sean L. Willis, Matthew R. Dreher, Andrew L. Lewis
Pediatrics Faculty Publications
The objective of this study was to undertake a comprehensive long-term biocompatibility and imaging assessment of a new intrinsically radiopaque bead (LC Bead LUMI™) for use in transarterial embolization. The sterilized device and its extracts were subjected to the raft of ISO10993 biocompatibility tests that demonstrated safety with respect to cytotoxicity, mutagenicity, blood contact, irritation, sensitization, systemic toxicity and tissue reaction. Intra-arterial administration was performed in a swine model of hepatic arterial embolization in which 0.22–1 mL of sedimented bead volume was administered to the targeted lobe(s) of the liver. The beads could be visualized during the embolization procedure with …
Controlled Delivery Of Angiogenic And Arteriogenic Growth Factors From Biodegradable Poly(Ester Amide) Electrospun Fibers For Therapeutic Angiogenesis,
2016
The University of Western Ontario
Controlled Delivery Of Angiogenic And Arteriogenic Growth Factors From Biodegradable Poly(Ester Amide) Electrospun Fibers For Therapeutic Angiogenesis, Somiraa S. Said
Electronic Thesis and Dissertation Repository
Therapeutic angiogenesis relies on the delivery of exogenous growth factors to stimulate neovessel formation. However, systemic administration of angiogenic factors results in rapid clearance from the site of interest due to their short biological half-life. In this work, we are reporting controlled delivery of a ‘cocktail’ of growth factors, an angiogenic factor −fibroblast growth factor-2 (FGF2), and an arteriogenic factor −fibroblast growth factor-9 (FGF9), from biodegradable poly(ester amide) (PEA) electrospun fibers towards targeting neovascular formation and maturation. FGF2 and FGF9 were dual loaded into PEA fibers using a mixed blend and emulsion electrospinning technique. Matrigel tube formation and Boyden chamber …
Cartilage Engineering: Optimization Of Media For Chondrogenic Differentiation In Vitro,
2016
Purdue University
Cartilage Engineering: Optimization Of Media For Chondrogenic Differentiation In Vitro, Evan Surma, Sherry L. Harbin, Hongji Zhang, Stacy Halum
The Summer Undergraduate Research Fellowship (SURF) Symposium
Lower back pain from intervertebral disc injury affects around 84% of the population at some point in their life, which at its worst may cause total immobilization. This pain can only be temporarily relieved by spinal fusion or intervertebral disc replacement; however, both of these cause loss of natural motion in patients by removing damaged fibrocartilage discs. While these techniques help mitigate pain briefly, no permanent solution exists currently to both relieve pain and preserve natural motion. My work may be a solution by eventually providing patient-specific implants that resemble native tissue in the regeneration process that could be absorbed …
Alginate Hydrogels As Three-Dimensional Scaffolds For In Vitro Culture Models Of Growth Plate Cartilage Development And Porcine Embryo Elongation,
2016
University of Nebraska - Lincoln
Alginate Hydrogels As Three-Dimensional Scaffolds For In Vitro Culture Models Of Growth Plate Cartilage Development And Porcine Embryo Elongation, Taylor D. Laughlin
Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research
The establishment of in vitro culture models utilizes tissue engineering principles to design functional mimics of in vivo environments in vitro. Advantages for the use of in vitro culture models include ethical alleviation of animal models for therapeutic testing, cost efficiency, and a greater ability to study specific mechanisms via a systematic, ground-up approach to development. In this thesis, alginate hydrogels are utilized in the development of in vitro culture models of porcine embryo elongation and growth plate cartilage development. First, the effect of scaffold and modifications to the scaffold were explored in both projects. In order to modulate …
Bioengineered Platforms To Study Carcinoma Cell Response To Drug Treatment,
2016
University of Massachusetts Amherst
Bioengineered Platforms To Study Carcinoma Cell Response To Drug Treatment, Thuy V. Nguyen
Doctoral Dissertations
The tumor extracellular matrix (ECM) plays an important role in facilitating tumor growth and mediating tumor cells' resistance to drugs. However, during drug development, potential chemotherapeutics are screened in plastic plates, which lack relevant ECM physicochemical cues. In order to improve drug development process, this dissertation includes the development of relevant 2D and 3D biomaterial systems that can be used to study carcinoma cell response to drug treatment. A novel poly(ethylene glycol)-phosphorylcholine (PEG-PC) high-throughput biomaterial platform was developed to study how the ECM mechanochemical properties affect cancer cells' response to drug. The PEG-PC biomaterial is optically transparent, has a mechanical …
Structure And Dynamics Of Charged Colloidal Disks In Colloid-Polymer Mixtures,
2016
University of Massachusetts Amherst
Structure And Dynamics Of Charged Colloidal Disks In Colloid-Polymer Mixtures, Suhasini Kishore
Doctoral Dissertations
Complex fluid mixtures of colloids and polymers are extensively used in several conventional and emerging technological applications. Particles self-assemble under different conditions to form colloidal glasses and gels and it often leads to the development of unusual viscoelastic features. In the case of aspherical particles, shape anisotropy and physical aging effects add to the existing complexities so the implementation of a strategic formulation method to improve performance and stability remains a critical challenge. This thesis presents a comprehensive analysis of particle interactions in mixtures of charged disk-shaped colloids and weakly-adsorbing polymers like poly(ethylene oxide) (PEO). Here, we discuss the behavior …
Prosthetic Leg Kit For Deployment In Developing Countries,
2016
California Polytechnic State University, San Luis Obispo
Prosthetic Leg Kit For Deployment In Developing Countries, Brian Murphy, Dominique Porcincula, Derek Morgan, Kendall Ruggles, Christian Aguayo
Biomedical Engineering
The World Health Organization estimates that over 30 million people require some sort of prosthetic technology. However, traditional prosthetic fitting practices take a lot of time and cost a lot of money, making them inaccessible to millions of people around the world. StandUP Worldwide is an interdisciplinary project team devoted to creating low-cost prosthetic technologies for use around the world, especially in resource poor areas. They are currently developing a low cost, below-the-knee prosthetic kit that can be easily deployed in a resource-poor area. The following presents their solution for a below-the-knee prosthetic socket, foot, and leg.
Inter-Droplet Membranes For Mechanical Sensing Applications,
2016
University of Tennessee - Knoxville
Inter-Droplet Membranes For Mechanical Sensing Applications, Nima Tamaddoni Jahromi
Doctoral Dissertations
This dissertation combines self-assembly phenomena of amphiphilic molecules with soft materials to create and characterize mechanoelectrical transducers and sensors whose sensing elements are thin-film bioinspired membranes comprised of phospholipids or amphiphilic polymers. We show that the structures of these amphiphilic molecules tune the mechanical and electrical properties of these membranes. We show that these properties affect the mechanoelectrical sensing characteristic and range of operation of these membrane transducers. In the experiments, we construct and characterize a membrane-based hair cell embodiment that enables the membrane to be responsive to mechanical perturbations of the hair. The resulting oscillations of membranes formed between …
Interaction Of Fibrinogen With Fibronectin: Purification And Characterization Of A Room Temperature-Stable Fibrinogen-Fibronectin Complex From Normal Human Plasma,
2016
University of Nebraska-Lincoln
Interaction Of Fibrinogen With Fibronectin: Purification And Characterization Of A Room Temperature-Stable Fibrinogen-Fibronectin Complex From Normal Human Plasma, Ayman E. Ismail
Department of Chemical and Biomolecular Engineering: Theses and Student Research
A fibrinogen-fibronectin complex (γγ’pdFI-pdFN) was purified from normal human plasma using a sequence of cryoprecipitation, ammonium sulfate fractionation, and DEAE Sepharose chromatography. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing condition showed both a 1:1 stoichiometric ratio of fibrinogen (FI) to fibronectin (FN) as well as a stoichiometric ratio of 1:1 of γg to gγ’. The γγ’pdFI-pdFN complex was non-covalent in nature as it was disrupted by affinity adsorption to Gelatin Sepharose where pdFN bound strongly and the disrupted γγ’pdFI fell through the chromatographic column. Surprisingly, the purified γγ’pdFI-pdFN complex was more broadly thermally stable than plasma FI (pdFI) …
Investigating The Mechanical Behaviors Of Organic/Inorganic Composite Bone Scaffolds,
2016
University of Arkansas, Fayetteville
Investigating The Mechanical Behaviors Of Organic/Inorganic Composite Bone Scaffolds, Parker Davidson
Biomedical Engineering Undergraduate Honors Theses
The regeneration of bone over a large area cannot occur without a structure for the bone cells to bind and divide. The use of an organic/inorganic composite bone scaffold appears to be a promising alternative to the current clinical standard of bone grafting. Bone grafting is very limited, in that the size and shape of the area are hard to replicate and the use of donor tissue can trigger an immunologic response resulting in rejection of the bone tissue. This study experimented with composite bone scaffolds which can be made to fit the shape of the area in which bone …
Customization Of Titanate Nanofiber Bioscaffolds,
2016
University of Arkansas, Fayetteville
Customization Of Titanate Nanofiber Bioscaffolds, Jared Hopkins
Biomedical Engineering Undergraduate Honors Theses
In the field of orthopedic devices implant loosening is a major issue resulting in the majority of device failures. These failures result in the need for costly secondary procedures. To reduce device loosening an improved method of tissue anchoring is required. A previously studied titanate nanofiber bioscaffold has been shown to be safely implantable and to contribute to the differentiation of mesenchymal stem cells to osteocytes. Through the customization of both physical and chemical characteristics this titanate nanofiber bioscaffold was fabricated as a potential means to enhance tissue anchoring for use with orthopedic devices. This customization was enabled by acoustic …
Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds,
2016
University of Arkansas
Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds, Jakob Hockman
Biomedical Engineering Undergraduate Honors Theses
Metallic single-walled carbon nanotubes (m-SWNTs) were separated from pristine SWNTs using affinity chromatography for use in electrically conductive tissue engineering scaffolds. Approximately one third of SWNTs have metallic properties. Separations were achieved using a protocol modified from Liu & coworkers (2011) in order to improve the method for cell culture environments. Samples enriched in m-SWNTs were isolated and characterized. However, challenges still remain for the complete separation of m-SWNTs from their semiconducting counterpart (s-SWNTs) using this protocol. Approaches to improve separation and reduce the difficulties associated with processing the nanotubes were suggested. One of the ultimate destinations of these nanotubes …
