Biomaterials Commons^™

Evaluation Of Alternative Solvents For Electrospinning Occluded Scaffolds To Model Intracranial Atherosclerotic Disease In Blood Vessel Mimics, Olivia D. Rankin

Master's Theses

Intracranial atherosclerotic disease (ICAD) is characterized by a buildup of fatty plaque within the walls of arteries supplying the brain, resulting in vessel narrowing, restricted blood flow, and increased risk of ischemic stroke. While various treatments exist for ICAD, most are accompanied by high recurrent stroke rates and other adverse events, highlighting the need for further investigation and models for pre-clinical testing. Tissue engineered Blood Vessel Mimics (BVMs), consisting of a polymer scaffold sodded with human vascular cells, serve as physiologically relevant in vitro models for vascular device testing. This thesis focused on the application of alternative solvents to a …

Pet Mobility Project, John Shelby, Lily-Rose Jolie Bacon, Andrea Yasmine Reyes

Biomedical Engineering

The Pet Mobility Project, sponsored by Terri Smith and Jasper Jackson, is an initiative aimed at providing a custom mobility aid to a pet in the San Luis Obispo community. Amber Rappozo’s young German Shepherd, LeDoux, was selected as the project’s recipient. LeDoux suffers from hindleg weakness and, as a result, has limited mobility. This document provides a comprehensive overview of the Pet Mobility Project, detailing the motivation, background, and design approach behind the development of a LeDoux’s custom mobility aid.

A Wearable-Based Approach To Spinal Posture Tracking And Assessment, Sydney Marie Sherman, Noah Jeffery

Biomedical Engineering: Graduate Reports and Projects

This paper describes the design, manufacturing, and testing of a novel spinal posture tracking wearable device with embedded sensors. Currently on the market, most of the spinal posture tracking devices only focus on one segment of the spine and therefore do not track the entirety of human posture. The objective for this project was to create a wearable device in the form of a “smart shirt” that offers insights into posture trends throughout the day by tracking the entire spine. To begin the project, multiple designs were developed for the sensor array and wearable materials. These concepts were compared against …

Novel Electrospinning Techniques For Fabricating Scaffolds To Model Intracranial Atherosclerotic Disease In Tissue Engineered Blood Vessel Mimics, Isaac "Squeaky" Buentipo

Master's Theses

Novel Electrospinning Techniques for Fabricating Scaffolds to Model Intracranial

Atherosclerotic Disease in Tissue Engineered Blood Vessel Mimics

Isaac “Squeaky” Buentipo

Dr. Kristen Cardinal’s Tissue Engineering Lab at California Polytechnic State University specializes in fabricating customized vascular models, known as Blood Vessel Mimics (BVMs), for medical device testing. BVMs are simplified in vitro vascular models designed to bridge the gap between bench testing and in vivo evaluation of intravascular medical devices. BVMs are produced by combining a polymer scaffold with human vascular cells. Through novel scaffold fabrication techniques, such as silicone injection molding, silicone dip casting and electrospinning, the capabilities of …

Manufacturing Silicone In-House For The Creation Of Customized Neurovascular Blood Vessel Mimics, Jacob Wilbert Perisho

Master's Theses

The Tissue Engineering Lab at California Polytechnic State University San Luis Obispo focuses on creating tissue-engineered Blood Vessel Mimics (BVMs) designed for the preclinical testing of neurovascular devices. These BVMs are composed of silicone models, representing anatomically accurate neurovasculatures, that are sodded with vascular cell types and then cultivated in bioreactors (which maintain physiologic conditions). These silicone models are currently sourced externally from industry partners, so the primary goal of this thesis was to develop the means and methods for the Tissue Engineering Lab to manufacture silicone models in-house.

The first aim of this thesis was to develop and explore …

Evaluation Of Polyvinyl Alcohol (Pva) For Electrospinning Utility In The Blood Vessel Mimic (Bvm) Lab, Logan Vandenbroucke

Master's Theses

Electrospinning has provided the opportunity to create extracellular matrix (ECM) mimicking scaffolds for the development of tissue-engineered constructs. Within Professor Kristen Cardinal’s Blood Vessel Mimic (BVM) Lab, at Cal Poly, there exists a constant demand for innovation and the expansion of polymer types and electrospinning capabilities for its BVM model. Along these lines, the BVM Lab has recently acquired two new electrospinning systems: the Spinbox, a commercially graded electrospinning system, and the Learn-By-Doing system, which was part of a recently completed thesis conducted by Jason Provol. Additionally, recently published literature has demonstrated polyvinyl alcohol (PVA) as a viable option for …

Eagle Medical Tray Denesting & Debris Removal Process, Nicholas Allen Ungefug, Noah Chavez, Susana Shu-Lin Okhuysen, Michael Augustine Pennington

Industrial and Manufacturing Engineering

Eagle Medical Incorporated is a contract medical device packaging and sterilization company. The company purchases thermoformed medical packaging trays, which maintain the sterility of medical devices, from various manufacturers. To ensure packaging quality and to prevent cleanroom contamination, Eagle Medical inspects and sterilizes each blister tray that they order. This process is an essential non-value-added activity that creates a bottleneck. Cleanroom employees must stop packaging medical devices and attend to the processing of blister trays and packaging solutions. The blister trays arrive at Eagle’s facility in nested stacks. Vibration and movement during shipping further compresses the stacks, which makes separation …

Insole Fall Prevention Device, Nick M. Hughes, Andrew M. Slaboda

Biomedical Engineering

Falls among the aging population occur every single day, with 1 in every 5 resulting in some injury and 300,000 hospitalized every year with a hip fracture [1]. The most popular and effective way to mitigate these falls is through physical therapist intervention. However, with the increased popularity in telerehab, many patients at risk for falls cannot accurately convey their gait tendencies to their physical therapists from the comfort of their home or while not in direct contact with the PT. A device like an insole, implanted with force sensors, which measures different parts of a patient’s foot, could convey …

Optimization Of A Novel Nipam-Based Thermoresponsive Copolymer For Intramuscular Injection As A Myoblast Delivery Vehicle To Combat Peripheral Artery Occlusive Disease, Quentin R. Klueter

Master's Theses

There is a need for a minimally invasive delivery method to enable cell therapies to combat peripheral artery occlusive disease (PAOD) in end stage patients. Myoblasts show promise as a cell mediated therapy but warrant an improved delivery method to increase cell retention in the region of interest because of their adherent nature, relative to previously used BM-MNC’s that are non-adherent. Contemporary issues with achieving successful cell therapies of vasculature can be mainly characterized by the lack of clinical translation from promising animal studies and absence of cell delivery scaffolding. Naturally, polymers have been widely experimented with as grafts to …

Evaluation Of Blood Vessel Mimic Scaffold Biocompatibility, Nicole M. Abraham

Master's Theses

The Tissue Engineering Research Lab at California Polytechnic State University, San Luis Obispo focuses on creating tissue-engineered blood vessel mimics (BVMs) for use in preclinical testing of vascular devices. These BVMs are composed of electrospun scaffolds made of an assortment of polymers that are seeded with different cell types. This integration of polymers with cells leads to the need for biocompatibility testing of the polymer scaffolds. Many of the lab’s newest scaffolds have not been fully characterized for biologic interactions. Therefore, the first aim of this thesis developed methods for in vitro cytotoxicity testing of polymers used in the fabrication …

The Impact Of Myoblast Transplantation On Collateral Capillary Arteriogenesis And Macrophage Phenotype, Christine Hue Do

Biomedical Engineering

Gangrene, pain, loss of limb function, amputation, and death are only few of the grievous consequences associated with peripheral arterial disease (PAD), a vascular disease caused by an obstruction that narrows the blood vessels. Since some patients have collateral vessels that can re-route blood to its downstream destination, much focus has been spotlighted upon discovering the mechanism of this process, termed arteriogenesis, as well as cell therapies to increase arterial diameter of collateral vessels. Since some patients do not have native pre-existing collateral vessels, another method to re-route blood is through arterialized collateral capillaries (ACC), which is the conversion of …

Computational Bone Mechanics Modeling With Frequency Dependent Rheological Properties And Crosslinking, Timothy G. Moreno

Master's Theses

Bone is a largely bipartite viscoelastic composite. Its mechanical behavior is determined by strain rate and the relative proportions of its principal constituent elements, hydroxyapatite and collagen, but is also largely dictated by their geometry and topology. Collagen fibrils include many segments of tropocollagen in staggered, parallel sequences. The physical staggering of this tropocollagen allows for gaps known as hole-zones, which serve as nucleation points for apatite mineral. The distance between adjacent repeat units of tropocollagen is known as D-Spacing and can be measured by Atomic Force Microscopy (AFM). This D-Spacing can vary in length slightly within a bundle, but …

Optimal Parameter Values For Accurate And Repeatable Nanoindentation Of Human Trabecular Bone, Stephen Matthew Kmak

Master's Theses

Nanoindentation techniques have not been standardized for use on bone tissues, making comparison of bone material properties obtained via nanoindentation across studies difficult and unreliable. This study determined a set of optimal parameter values for thermal drift correction time, dwell time, and loading rate that can be used to obtain accurate and repeatable material properties from human femoral trabecular bone through experimentation and statistical analysis. All testing was conducted using a single nanoindenter on a single trabeculae, with the assumption that material properties within the individual trabeculae were internally consistent. Parameters not of interest during this study, such as ambient …

Solostand, Hau Nhat Doan, Sydney Gray, Celina Dioso

Biomedical Engineering

The purpose of this scope of work is to highlight the progress and development of SoloStand sponsored by Derek Herrera, chief technical officer and founder of SpinalSingularity. SoloStand is an attachment to a wheelchair that will benefit paraplegics that use wheelchairs. A portable and customizable attachment to a wheelchair will allow the user to do everyday tasks without transferring into a separate standing wheelchair and travel more easily. This document outlines everything that has been done in fulfillment of our senior project requirements.

Compositional Optimization Of Amyloid-Graphene Oxide Nanohybrids For Biomaterials, Claire L. Drewery

Materials Engineering

Amyloid nanofibrils are natural materials capable of self-assembling into precise structures with tunable functionalities, while exhibiting excellent mechanical properties. In combination with highly conductive graphene oxide (GO), the 1-D amyloid nanofibrils and 2-D nanosheets of GO can produce a robust and bio-functional nanohybrid, hypothesized to exhibit multi-domain functional properties useful for enzyme sensing, water purification, drug delivery, and tissue scaffolding applications. Here, we examine the properties of an amyloid-graphene oxide nanohybrid film made with amyloids derived from hen egg white lysozymes in an attempt to explore the diverse toolbox of amyloid derivatives and establish ideal fabrication methods and formulations of …

Nano Fab Lab 63, Brian K. Deemer, Josh Clemons, Nick Brodine, Delaney Fitzsimmons

Mechanical Engineering

Lawrence Livermore National Laboratories (LLNL) has several steps in the production process for ceramic nanofiber tubes that they would like to improve - electrospinning, cutting, rolling, sealing and heat treating. We undertook the challenge to deliver LLNL with a semi-automated process that efficiently integrates the steps of cutting, rolling, and sealing to save time and improve control over end dimensions. In this document, we discuss the technical background of the manufacturing steps currently followed to create nanofiber tubes, identify which steps are incorporated in our prototype and explain how they will interface with one another, define the design requirements, present …

Evaluation Of Human Umbilical Vein Endothelial Cells In Blood Vessel Mimics Through Changes In Gene Expression And Caspase Activity, Conor Charles Hedigan

Master's Theses

Blood vessel mimics (BVMs) are simple tissue engineered blood vessel constructs intended for preclinical testing of vascular devices. This thesis developed and implemented methods to characterize two of these components. The first aim of this thesis investigated the effect of cell culture duration and flow conditions on endothelial cell gene expression, especially regarding endothelial-to-mesenchymal transition (EndMT). A trend of decreased endothelial marker gene expression and increased mesenchymal marker gene expression would indicate EndMT. qPCR analysis revealed that increased cell culture duration did not result in EndMT, and in fact increased endothelial marker expression as cell culture duration increased. Disturbed flow …

Analysis Of The Low-Cycle Fatigue Behavior Of Silicone Rubber For Biomedical Balloons, Chase Cooper

Materials Engineering

The development of a medical drug delivery device that allows for the deployment drugs into the adventitial tissue of blood vessels requires the inflation of a silicone elastomer. The inflated silicone must be able to consistently endure multiple loading cycles without failing so that the device can operate reliably. There are multiple methods of processing the silicone for the device and the goal of this study is to examine the effect of the various processing methods on the characteristics of the silicone. The Dynamic Mechanical Analysis Machine (DMA) is used to model the conditions of the device’s application by performing …

Identifying And Reducing Variability, Improving Scaffold Morphology, And Investigating Alternative Materials For The Blood Vessel Mimic Lab Electrospinning Process, Evan M. Dowey

Master's Theses

The work of the Cal Poly Tissue Engineering Lab is primarily focused on the fabrication, characterization, and improvement of “Blood Vessel Mimics” (BVMs), tissue engineered constructs used to evaluate cellular response to vascular medical devices. Currently, cells are grown onto fibrous, porous tubes made using an in-house electrospinning process from PLGA, a biocompatible co-polymer. The adhesion and proliferation of cells in a BVM is reliant on the micro-scale structure of the PLGA scaffold, and as such it is of great importance for the electrospinning process to consistently produce scaffolds of similar morphologies. Additionally, it has been shown that cell proliferation …

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 …

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.

Molecular Dynamics Investigation Of The Arabinan-Cellulose Interface For Cellulose Nanocomposite Applications, Luke Thornley

Materials Engineering

Atom level computer simulations of the arabinan and cellulose interface were performed to better understand the mechanisms that give arabinan-cellulose composites (ArCCs) their strength with the goal to improve man-made ArCCs. The molecular dynamics (MD) software LAMMPS was used in conjunction with the ReaxFF/c force field to model the bond between cellulose and arabinan. A cellulose nanocrystal with dimensions 51 x 32 x 8 Å was minimized with various weight percent of water, 0%, 3%, 5%, 8%, 10%, and 12%. After the system was equilibrated for at least 100,000 femtoseconds, an arabinan molecule composed of 8 arabinose rings was added …

Renal Artery Stent Fatigue Test, Braden Cooper, Munir Eltal, Jennifer Hawthorne, Ashley Schaefer

Mechanical Engineering

In today’s world of medical innovation, regulations and requirements set by organizations such as the Food and Drug Administration (FDA), the International Organization for Standardization (ISO), and ASTM International (American Society for Testing and Materials) can inhibit rapid innovation by demanding rigorous testing of new designs. For arterial stents, the standard is that each design must be tested to simulate 10 years of life in an environment congruent to an in vivo environment. Endologix in Irvine, California develops and manufactures minimally invasive treatments for aortic diseases, with a focus on stent grafts for the treatment of abdominal aortic aneurysms (AAA). …

Self-Contained Breathing Apparatus For Firefighter With A Permanent Stoma, Jason Delgadillo, Aaron Wheeler, Zachary Wishbow

Biomedical Engineering

The purpose of this project was to create a unique SCBA (self-contained breathing apparatus) for a firefighter named Chris Gauer. This prototype consists of a SCBA headgear connected to a polycarbonate-formed stoma mask with a medical-grade sanitary silicone hose.

A Rubric For Electrochemical Testing Of Metallic Biomaterials, Frederick G. De La Fuente

Master's Theses

Corrosion is a major factor for the failure of metallic medical implants. Testing a metal’s suseptability to corrosion prior to implantation is key to a successful implantation. Electrochemical processes were used in this study to evaluate the characteristics of corrosion of both AISI 316 stainless steel and titanium alloy Ti6Al4V, welded and non-welded. Linear, potentiodynamic, and cyclic polarization curves were produced by the PARC 2273 potentiostat showing the corrosion tendencies of the metals in four unique solutions 3.5% NaCl, 0.35% NaCl, phosphate buffered saline solution (PBS), and Butterfield phosphate buffered solution (BPS). The concentration of chloride ions in solutions affected …

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 …

Characterizing The Reproducibility Of The Properties Of Electrospun Poly(D, L-Lactide-Co-Glycolide) Scaffolds For Tissue-Engineered Blood Vessel Mimics, Toni M. Pipes

Master's Theses

“Blood vessel mimics” (BVMs) are tissue-engineered constructs that serve as in vitro preclinical testing models for intravascular devices. The Cal Poly Tissue Engineering lab specifically uses BVMs to test the cellular response to stent implantation. PLGA scaffolds are electrospun in-house using the current “Standard Protocol” and used as the framework for these constructs. The performance of BVMs greatly depends on material and mechanical properties of the scaffolds. It is desirable to create BVMs with reproducible properties so that they can be consistent models that ultimately generate more reliable results for intravascular device testing. Reproducibility stems from the consistency of the …

Clear Circuit Contact Lens, Paul Hecker Ii, Phillip Azar, Alexander Do, Benny Ng, Errol Leon

Electrical Engineering

The clear active contact lens project aims to address safety and hazard awareness with an unexplored field of eye wear technology. With advancements in nanotechnology and the advent of circuits on contact lens, this project is one of the first research and development into this new field, following University of Washington and Google. The team focuses on the safety and biocompatibility of the contact lens for a comfortable ease of use. The designs push the limits of thin film printed technology with its pursuit of fine designs of 250μm antennas. The project streamlines the manufacturing process for a combination substrate …

Material Differences In Equine Cortical And Trabecular Bone, Ryan B. Allen

Master's Theses

A greater understanding of bone materials would be beneficial in creating more accurate computer models and in the making of biomedical products involving bone. This study set out to determine whether cortical and trabecular bone are two separate materials, or whether they are the same material with a variance in porosity. To answer this question, samples were taken from different sections of the equine metacarpus, underwent densitometry analysis and were statistically analyzed. The majority of results suggest that the material is the same between varying densities of bone and thus the same between cortical and trabecular bone. These particular results …

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. …