Biomaterials Commons^™

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 …

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 …

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 …

Equilibrium Testing Of Rat Tail Tendon: An Analysis Of The Viscoelastic Properties Of Collagen Under Different Strain Points, Joshua C. Witt

Graduate Theses - Biology & Biomedical Engineering

Instantaneous tensile testing and stress-relaxation testing are forms of mechanical testing used to determine the elastic and viscoelastic properties of biological tissue. Equilibrium testing is a form of testing that combines both of these testing approaches at different strain points to determine the elastic properties of a material and also assess their viscoelastic properties in the same test. This testing method is commonly used on highly viscoelastic materials such as cartilage but has never been fully described in dense collagenous materials such as tendon or ligament. This analysis utilizes different strain points selected to capture the classic non-linear behavior of …

Surface-Initiated Polymerizations For The Rapid Sorting Of Rare Cancer Cells, Jacob L. Lilly

Theses and Dissertations--Chemical and Materials Engineering

Cancer metastasis directly accounts for an estimated 90% of all cancer related deaths and is correlated with the presence of malignant cells in systemic circulation. This observed relationship has prompted efforts to develop a fluid biopsy, with the goal of detecting these rare cells in patient peripheral blood as surrogate markers for metastatic disease as a partial replacement or supplement to tissue biopsies. Numerous platforms have been designed, yet these have generally failed to support a reliable fluid biopsy due to poor performance parameters such as low throughput, low purity of enriched antigen positive cells, and insufficiently low detection thresholds …

Inhibition Of Bacterial Growth And Prevention Of Bacterial Adhesion With Localized Nitric Oxide Delivery, Julia Osborne

Dissertations, Master's Theses and Master's Reports

Bacterial infections continue to be a problem at the site of an indwelling medical device, and over the years, various bacterial strains have become more resistant to current antibiotic treatments. Bacterial infection at an indwelling medical device can be dangerous and affect the performance of the medical device which can ultimately lead to the failure of the device due to bacterial resistance to treatment.

Nitric Oxide (NO) has been shown to possess antibacterial properties to prevent and inhibit bacterial growth. NO releasing coatings on indwelling medical devices could provide a reduction in bacterial infections that occur at the device site …

Design And Development Of Two Component Hydrogel Ejector For Three-Dimensional Cell Growth, Thomas Dunkle, Jessica Deschamps, Connie Dam

Honors Scholar Theses

Hydrogels are useful in wound healing, drug delivery, and tissue engineering applications, but the available methods of injecting them quickly and noninvasively are limited. The medical industry does not yet have access to an all-purpose device that can quickly synthesize hydrogels of different shapes and sizes. Many synthesis procedures that have been developed result in the formation of amorphous hydrogels. While generally useful, amorphous hydrogels exhibit limited capability in tissue engineering applications, especially due to their viscous properties. This endeavor aims to modulate the appropriate gelation parameters, optimize the injection process, and create a prototype that allows for the extrusion …

Engineering Approaches For Suppressing Deleterious Host Responses To Medical Implants, Connor Mccarthy

Dissertations, Master's Theses and Master's Reports

Small diameter (< 6 mm) vascular grafts suffer from serious deleterious effects not encountered with their larger diameter relatives, leading to premature graft failure through restenosis. Platelet activation, inflammation, and smooth muscle cell proliferation are leading contributors to thrombosis and neointimal hyperplasia, both contributors to the progression of restenosis. It may be possible to suppress negative biological responses to vascular implants through the modification of surface properties and incorporation of drug release into blood contacting materials. In this work, bioengineering approaches are presented to improve the biocompatibility of small diameter vascular grafts.

We demonstrate a novel engineering approach for incorporating natural, decollagenized elastin matrices into PEU 1074A reinforced vascular grafts through spray-coating and electrospinning processes in a manner that retains elastin’s excellent blood contacting properties. A vascular construct with excellent mechanical and surgical handling properties demonstrating the suppression of neointimal hyperplasia is presented after 21 days in vivo.

Nitric oxide (NO) has been investigated over the past several decades due to its platelet, inflammation, and smooth muscle cell suppressing effects; and if appropriately delivered, could positively mediate the contributors to restenosis. Here, we characterize a novel macrocyclic NO …

Peracetic Acid: A Practical Agent For Sterilizing Heat-Labile Polymeric Tissue-Engineering Scaffolds, William R. Trahan

Theses and Dissertations

Advanced biomaterials and sophisticated processing technologies aim to fabricate tissue-engineering scaffolds that can predictably interact within a biological environment at a cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed prior to clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone (PCL), a low melting polymer, and …

Low Molecular Weight Glucosamine/L-Lactide Copolymers As Potential Carriers For The Development Of A Sustained Rifampicin Release System: Mycobacterium Smegmatis As A Tuberculosis Model, Jorge Ragusa

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Tuberculosis, a highly contagious disease, ranks as the second leading cause of death from an infectious disease, and remains a major global health problem. In 2013, 9 million new cases were diagnosed and 1.5 million people died worldwide from tuberculosis. This dissertation aims at developing a new, ultrafine particle-based efficient antibiotic delivery system for the treatment of tuberculosis. The carrier material to make the rifampicin (RIF)-loaded particles is a low molecular weight star-shaped polymer produced from glucosamine (molecular core building unit) and L-lactide (GluN-LLA). Stable particles with a very high 50% drug loading capacity were made via electrohydrodynamic atomization. Prolonged …

A Collagen‐Glycosaminoglycan‐Fibrin Scaffold For Heart Valve Tissue Engineering Applications, Claire Brougham, Stefan Jockenhoevel, Thomas Flanagan, Fergal O'Brien

Conference Papers

The field of heart valve biology and tissue engineering a heart valve continue to expand. The presentatio ns at this meeting reflect the advances made in both areas due to the multi-disciplinary approach taken by many laboratories.

Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes

Master's Theses

The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual examination of suspicious regions …

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

Results …

Bioerodible Calcium Sulfate Bone Grafting Substitutes With Tailored Drug Delivery Capabilities, Bryan R. Orellana

Theses and Dissertations--Biomedical Engineering

Bone regeneration or augmentation is often required prior to or concomitant with implant placement. With the limitations of many existing technologies, a biologically compatible synthetic bone grafting substitute that is osteogenic, bioerodible, and provides spacing-making functionality while acting as a drug delivery vehicle for bioactive molecules could provide an alternative to ‘gold standard’ techniques.

In the first part of this work, calcium sulfate (CS) space-making synthetic bone grafts with uniformly embedded poly(β-amino ester) (PBAE) biodegradable hydrogel particles was developed to allow controlled release of bioactive agents. The embedded gel particles’ influence on the physical and chemical characteristics of CS was …

Evaluation Of Tissue-Engineered Tendon Enthesis Polymer Constructs, Joshua A. Bundy Bs, Mary Beth Wade Phd, Hitomi Nakao Md, Phillip Mcclellan Phd, Qing Yu Phd, Robin Jacquet-Childs Ms, William J. Landis Phd

Williams Honors College, Honors Research Projects

Both scientists and clinicians have proposed tissue engineering as the future of medicine. The possibilities for tissue engineering, that is, fabrication of tissues and organs in the laboratory and their translation to patients, appear to be endless, and many believe that this new approach in medicine will result in abolishing many common ailments, injuries, and congenital defects. Injuries to a tendon enthesis, the normal tissue connection between tendon and bone, are of particular concern to clinicians because of their frequency and failure to repair as a result of surgery. While these injuries may not be life threatening, they can certainly …

Fluorescence Characterization Of Quantum Dots For Use As Biomarkers, Logan M. Grimes

Materials Engineering

Fluorescence profiles of quantum dots (QDs) were characterized to select the ideal QDs for encapsulation in phospholipids for use as biomarkers to selectively adhere to cancer cells. QDs were synthesized and extracted 0, 30, 60, and 90 seconds after precursor compounds were mixed. These extractions were isolated by extraction time. Portions from each vial were coated in a zinc sulfide shelling procedure, leaving at least half of the QD solution unshelled. These samples were characterized over four days to monitor fluctuations in fluorescence. This was done utilizing an Ocean Optics spectrometer in conjunction with Spectra Suite software. The central wavelength, …

Closed Loop Control Of A Cylindrical Tube Type Ionic Polymer Metal Composite (Ipmc), Benjamin Mead

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this research is to provide a framework for the integration of tube type, cylindrical Ionic Polymer Metal-Composite (IPMC) into conventional devices. IPMCs are one of the most widely used types of electro-active polymer actuator, due to their low electric driving potential and large deformation range. For this research a tube type IPMC was investigated. This IPMC has a circular cross section with four separate electrodes on its surface and a hole through the middle. The four electrodes allow for biaxial bending and accurate control of the tip location. One of the main advantages of using this type …

Growth And Expression Of Halorhodopsin For Application In A Protein-Based Artificial Retina, Megan Ryan Gillespie

Honors Scholar Theses

Halorhodopsin (HR), a light-activated chloride ion pump, demonstrates potential for use as the scaffolding in an artificial retina. Retinal implants are needed to restore vision to people afflicted with ophthalmic diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). A protein-based chloride ion-patch would be utilized by the eye to create an influx of chloride ions, similar to ion concentrations in healthy retinas during the conversion of light stimuli to electrochemical signals. This protein-based retinal prosthesis will directly stimulate the bipolar cells of the retina, replacing the function of damaged photoreceptor cells. Other alternative treatments for AMD and …

A Preliminary Study On The Potential Of Manuka Honey And Platelet-Rich Plasma In Wound Healing, Scott A. Sell, Patricia S. Wolfe, Andrew J. Spence, Isaac A. Rodriguez, Jennifer M. Mccoll, Rebecca L. Petrella, Koyal Garg, Jeffery J. Ericksen, Gary L. Bowlin

Ellmer School of Nursing Faculty Publications

Aim. The purpose of this study was to determine the in vitro response of cells critical to the wound healing process in culture media supplemented with a lyophilized preparation rich in growth factors (PRGF) and Manuka honey. Materials and Methods. This study utilized cell culture media supplemented with PRGF, as well as whole Manuka honey and the medical-grade Medihoney (MH), a Manuka honey product. The response of human fibroblasts (hDF), macrophages, and endothelial cells (hPMEC) was evaluated, with respect to cell proliferation, chemotaxis, collagen matrix production, and angiogenic potential, when subjected to culture with media containing PRGF, MH, Manuka honey, …

Targeted Multistage Delivery Of Nanoparticles To The Bone Marrow, Aman Mann

Dissertations and Theses (Open Access)

Bone marrow is a target organ site involved in multiple diseases including myeloproliferative disorders and hematologic malignancies and metastases from breast and prostate. Most of these diseases are characterized with poor quality of life, and the treatment options are only palliative due to lack of delivery mechanisms for systemically injected drugs which results in dose limitation to protect the healthy hematopoietic cells. Therefore, there is a critical need to develop effective therapeutic strategies that allow for selective delivery of therapeutic payload to the bone marrow. Nanotechnology-based drug delivery systems provide the opportunity to deliver drugs to the target tissue while …

Synthesis Of An Endothelial Cell Mimicking Surface Containing Thrombomodulin And Endothelial Protein C Receptor, Karl E. Kador

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Synthetic materials for use in blood contacting applications have been studied for many years with limited success. One of the main areas of need for these materials is the design of synthetic vascular grafts for use in the hundreds of thousands of patients who have coronary artery bypass grafting, many without suitable veins for autologous grafts. The design of these grafts is constrained by two common modes of failure, the formation of intimal hyperplasia (IH) and thrombosis. IH formation has been previously linked to a mismatching of the mechanical properties of the graft and has been overcome by creating grafts …

Destruction Of Α -Synuclein Based Amyloid Fibrils By A Low Temperature Plasma Jet, Erdinc Karakas, Agatha Munyanyi, Lesley Greene, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the plasma pencil, a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.

Desulfovibrio Desulfuricans G20 Tetraheme Cytochrome Structure At 1.5 A˚ And Cytochrome Interaction With Metal Complexes, Mrunalini Pattarkine, J J. Tanner, C A. Bottoms, Y H. Lee, Judy D. Wall

Faculty Works

The structure of the type I tetraheme cytochrome c3 from Desulfovibrio desulfuricans G20 was determined to 1.5 A˚ by X-ray crystallography. In addition to the oxidized form, the structure of the molybdate-bound form of the protein was determined from oxidized crystals soaked in sodium molybdate. Only small structural shifts were obtained with metal binding, consistent with the remarkable structural stability of this protein. In vitro experiments with pure cytochrome showed that molybdate could oxidize the reduced cytochrome, although not as rapidly as U(VI) present as uranyl acetate. Alterations in the overall conformation and thermostability of the metal-oxidized protein were investigated …

Studies On The Formation Of Dna-Cationic Lipid Composite Films And Dna Hybridization In The Composites, Murali Sastry, Vidya Ramakrishnan, Mrunalini Pattarkine, Krishna N. Ganesh

Faculty Works

The formation of composite films of double-stranded DNA and cationic lipid molecules (octadecylamine, ODA) and the hybridization of complementary single-stranded DNA molecules in such composite films are demonstrated. The immobilization of DNA is accomplished by simple immersion of a thermally evaporated ODA film in the DNA solution at close to physiological pH. The entrapment of the DNA molecules in the cationic lipid film is dominated by attractive electrostatic interaction between the negatively charged phosphate backbone of the DNA molecules and the protonated amine molecules in the thermally evaporated film and has been quantified using quartz crystal microgravimetry (QCM). Fluorescence studies …

Energy Loss And Stiffness Properties Of Dynamic Elastic Response Prosthetic Feet, Mark Geil

Faculty Articles

No abstract provided.

Cationic Surfactant Mediated Hybridization And Hydrophobization Of Dna Molecules At The Liquid/Liquid Interface And Their Phase Transfer, Murali Sastry, Ashavani Kumar, Mrunalini Pattarkine, Vidya Ramakrishnan, Krishna N. Ganesh

Faculty Works

Hybridization of complementary oligonucleotides mediated by a cationic surfactant at the water/hexane interface leads to hydrophobic, double-helical DNA which may be readily phase transferred to the organic phase and cast into thin films on solid substrates.

Hybridization Of Dna By Sequential Immobilization Of Oligonucleotides At The Air-Water Interface, Murali Sastry, Vidya Ramakrishnan, Mrunalini Pattarkine, Anand Gole, K. N. Ganesh

Faculty Works

The hybridization of DNA by sequential electrostatic and hydrogen-bonding immobilization of single-stranded complementary oligonucleotides at the air-water interface with cationic Langmuir monolayers is demonstrated. The complexation of the single-stranded DNA molecules with octadecylamine (ODA) Langmuir monolayers was followed in time by monitoring the pressure-area isotherms. A large (and slow) expansion of the ODA monolayer was observed during each stage of complexation in the following sequence: primary single-stranded DNA followed by complementary single-stranded DNA followed by the intercalator, ethidium bromide. Langmuir-Blodgett (LB) films of the ODA-DNA complex were formed on different substrates and characterized using quartz-crystal microgravimetry (QCM), Fourier transform infrared …

Anion Induced Blue To Purple Transition In Bacteriorhodopsin, Mrunalini Pattarkine, Anil K. Singh

Faculty Works

Purple membrane (PM, λ" role="presentation">λmax" role="presentation">max 570 nm) of H. halobium on treatment with sulphuric acid changes its colour to blue (λ" role="presentation">λmax" role="presentation">max 608 nm). The purple chromophore can be regenerated from the blue chromophore by exogeneous addition of anions such as CI−" role="presentation">− and HPO42−" role="presentation">2−4. Chloride ion is found to be more effective than the dibasic phosphate ion in regenerating the purple chromophore. Nevertheless, one thing common to the anion regeneration is that both CI−" role="presentation">− and HPO42−" role="presentation">2−4 show marked pH effect. At pH 1.0 the efficiency of …