Engineering Commons^™

Insect Antennae As Bioinspirational Superstrong Fiber-Based Microfluidics, Griffin J. Donley

All Theses

Nature is frequently turned to for inspiration for the creation of new materials. Insect antennae are hollow, blood-filled fibers with complex shape, and are cantilevered at the head. The antenna is muscle-free, but the insect can controllably flex, twist, and maneuver it laterally. To explain this behavior, a comparative study of structural and tensile properties of the antennae of Periplaneta americana (American cockroach), Manduca sexta (Carolina hawkmoth), and Vanessa cardui (painted lady butterfly) was performed. These antennae demonstrate a range of distinguishable tensile properties, responding either as brittle fibers (Manduca sexta) or strain-adaptive fibers that stiffen when stretched (Vanessa cardui …

Tissue Equivalent Gellan Gum Gel Materials For Clinical Mri And Radiation Dosimetry, Pawel Brzozowski

Electronic Thesis and Dissertation Repository

Hydrogels contain high amount of water allowing their use as surrogates to human tissues with specific properties that can be tuned by additives. Gellan gum is a gel-forming material of interest and is a replacement for other common gelling agent with limited use as a tissue phantom. Therefore, this thesis examines the application of gellan gum gels as a novel magnetic resonance imaging (MRI) phantom with a design of experiments model to obtain tunable properties. The analysis was extended to include mechanical and electrical properties with a separate design of experiment. Gels doped with synthesized superparamagnetic iron oxide nanoparticles (SPIONs) …

Covalently Crosslinked Organic/Inorganic Hybrid Biomaterials For Bone Tissue Engineering Applications, Dibakar Mondal

Electronic Thesis and Dissertation Repository

Scaffolds are key components for bone tissue engineering and regeneration. They guide new bone formation by mimicking bone extracellular matrix for cell recruitment and proliferation. Ideally, scaffolds for bone tissue engineering need to be osteoconductive, osteoinductive, porous, degradable and mechanically competent. As a single material can not provide all these requirements, composites of several biomaterials are viable solutions to combine various properties. However, conventional composites fail to fulfil these requirements due to their distinct phases at the microscopic level. Organic/inorganic (O/I) class II hybrid biomaterials, where the organic and inorganic phases are chemically crosslinked on a molecular scale, hence the …

Characterization Of Fibrin Matrix Incorporated Electrospun Polycaprolactone Scaffold, Cho Yi Wong

Theses and Dissertations

Specific objective: Guided tissue regeneration (GTR) aims to regenerate the lost attachment apparatus caused by periodontal disease through the use of a barrier membrane. For the GTR procedures to be successful, barrier membranes are required to be present at the surgical site for an extended period of time (weeks to months). Synthetic membranes have the advantage of prolonged presence in a wound site; however, they do not actively contribute to wound healing. Biologic membranes are recognized by the host tissue and participate in wound healing but have the disadvantage of early resorption. Therefore, the goal of this study is …

Layered, Flexible Drug Delivery Films For The Prevention Of Fibrotic Scar Tissue Formation, Cheryl L. Rabek

Theses and Dissertations--Biomedical Engineering

Open wounds account for about 50% of military injuries and 10% of non‐fatal traffic injuries. Scar tissue formation in these wounds may be reduced or prevented if treated with a combination of molecules whose release is tuned to the healing phases. The goal of this research was to develop flexible, layered drug delivery films for sequential, localized release of anti‐inflammatory, anti‐oxidant, and anti‐fibrotic molecules to soft tissue.

Films were composed of cellulose acetate phthalate (CAP) and Pluronic F‐127 (Pluronic). To impart flexibility, plasticizers, triethyl citrate (TEC) or tributyl citrate (TBC), were added. Mechanical analysis was performed on films as prepared …

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. …

Sol-Gel Derived Biodegradable And Bioactive Organic-Inorganic Hybrid Biomaterials For Bone Tissue Engineering, Bedilu A. Allo

Electronic Thesis and Dissertation Repository

Treatments of bone injuries and defects have been largely centered on replacing the lost bone with tissues of allogeneic or xenogeneic sources as well as synthetic bone substitutes, which in all lead to limited degree of structural and functional recovery. As a result, tissue engineering has emerged as a viable technology to regenerate the structures and therefore recover the functions of bone tissue rather than replacement alone. Hence, the current strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate and function.

In this …

Poly(Vinyl Alcohol) Nanocomposite Hydrogels For Intervertebral Disc Prostheses, Elaine Wong

Electronic Thesis and Dissertation Repository

Spinal fusion is currently the gold standard for surgical intervention of intervertebral disc (IVD) diseases leading to neck and back pain failing conservative treatments. However, fusion removes motion between the vertebrae and can result in adjacent level degeneration. Total disc replacement (TDR) is an emerging treatment alternative that preserves motion, but materials found in clinically available devices bear little resemblance to the properties of the native IVD. Poly(vinyl alcohol) (PVA) hydrogels are biocompatible, have mechanical behaviour similar to natural tissues, and properties that can be tuned by varying polymer concentration and physical crosslinking through freeze-thaw cycling. Furthermore, their properties can …