Biomedical Engineering and Bioengineering Commons^™

St. Jude Medical: Pulmonary Edema Monitoring In Pacemakers And Icds, David Wei-Péng Chang

Master's Theses

Pulmonary edema occurs when fluid leaks from the pulmonary capillary network into the lung interstitium and alveoli. When the heart is not able to pump blood to the body efficiently, fluid can back up into the veins that take blood through the lungs to the left atrium. This then builds up the pressure in the blood vessels and fluid is pushed into the alveoli in the lungs. The fluid reduces normal oxygen movement through the lungs and can cause impaired gas exchange and respiratory failure. There are many causes of congestive heart failure that may lead to pulmonary edema such …

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 …

Functional 3-D Cellulose & Nitrocellulose Paper-Based, Multiplex Diagnostic Platforms Without Coupling Agents, Mackenzie Elizabeth Tageson

Master's Theses

The purpose of this thesis was to demonstrate device functionality of 3-D paper-based, multiplex platforms, µPADs, without the use of coupling agents between layers. Previously, these platforms were fabricated with double-sided tape and cellulose powder to try to augment proper fluid routing, but difficulties with this method occurred. An acrylic housing unit with strategically placed pressure tabs was designed to aid horizontal and vertical fluid routing through the platform, thus eliminating the inconsistencies associated with coupling agents. Channel characterization studies, a COMSOL^TM simulation, and development time studies were performed to aid device design and demonstrate device functionality.

The implementation …

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 …

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. …

Mechanoadaptation Of Feed Artery Smooth Muscle Cells In The Stem Of The Collateral Circulation, Allison Peck

Biomedical Engineering

Many patients suffering from peripheral arterial occlusive disease (PAOD) experience intermittent claudication, pain during locomotion. Previous studies suggest that this symptom could be explained in part by impaired vasodilation in collateral arteries. In this study, femoral ligation was performed on a murine animal model, stimulating collateral outward remodeling. The mechanism by which a collateral increases its luminal diameter in response to the increase in blood flow following occlusion warrents further investigation due to impaired vasodilation following collateral remodeling. Specifically, resting diameter is elevated in the stem region of the collateral circuit, but this increase in vessel size cannot be explained …

An Analysis Of Eliminating Electroosmotic Flow In A Microfluidic Pdms Chip, Cecile D. Redington

Master's Theses

The goal of this project is to eliminate electroosmotic flow (EOF) in a microfluidic chip. EOF is a naturally occurring phenomenon at the fluid-surface interface in microfluidic chips when an electric field is applied across the fluid. When isoelectric focusing (IEF) is carried out to separate proteins based on their surface charge, the analytes must remain in the separation chamber, and not migrate to adjacent features in the microfluidic chip, which happens with EOF.

For this project, a microfluidic chip was designed and commissioned to be photolithographically transferred onto a Si wafer. A PDMS component was then casted on the …

Vascular Reactivity Of Immature Arterialized Capillaries, Sara Hellstrom

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) is a globally prevalent cardiovascular disease in which atherosclerotic plaques narrow arterial lumen diameters and restrict blood flow to down stream tissues. The impact of these occlusions can be mitigated by collateral vessels that connect parallel arterial branches and act as natural bypasses to maintain perfusion. Some patients with PAOD may not have robust collateral networks to accommodate ischemic tissues in the event of an occlusion and, therefore, may be more susceptible to hypoxia and tissue necrosis. In animal models that lack collateral arterioles, capillaries can arterialize and form functional collaterals; however, in the early …

The Effects Of Variation In Collagen D-Spacing On Compact Bone Viscoelasticity: A Finite Element Analysis, Miguel A. Mendoza

Master's Theses

The D-spacing that is characteristic of collagen and its structural arrangement was previously thought to be a constant value. Much research is revealing that it is actually a distribution of values in biological tissues. Recent ovine experimentation has also shown that the D-spacing distribution is significantly altered following estrogen depletion. While ewes contain some major biological differences between their human counterparts, they are an economical and robust large animal model for postmenopausal osteoporosis. So, the exploration of the possible implications that D-spacing has on the mechanical properties of the whole bone utilizing animal models and computational methods is warranted. Six …

A Lateral Flow Smart Phone Image Analysis Diagnostic, Christina Holly Tyrrell

Master's Theses

A low cost compact diagnostic has many implications in today’s society. Smart phone technology has exponentially grown and with it the imaging capabilities associated with smart phones. The goals of this research are i) to determine the feasibility of combining in the field smart phone images with color dependent assay results, ii) to develop a MatLab® image analysis code to analyze these results, and iii) compare limits of detection between the un-aided eye and MatLab® image analysis software.

Orange G dye is used to create a stock solution and subsequent titers for analysis. Autocad is used to design an assay …

Finite Element Analysis And Validation Of Hip Joints With The Main Types Of Femoroacetabular Impingement, Kevin Lucas Mitchell

Master's Theses

Current research suggests that femoroacetabular impingement can be a cause of osteoarthritis. Femoroacetabular impingement is a condition that can affect both the femur and the pelvis of an individual. Femoroacetabular impingement can cause damage to the hip joint and its surrounding tissues. The articular cartilage and the labrum are both affected by this condition. A cam impingement is where a bony protrusion develops at the femoral head/neck junction. A pincer impingement is where a bony protrusion develops at the acetabular rim. Often, patients are seen with a combination of both impingements. The main goal of this study was to computationally …

Surgical Tooling Designed For The Direct Anterior Approach To Total Hip Arthroplasty, Jon-Peter Meckel

Master's Theses

Surgical Tooling Designed for the Direct Anterior Approach to Total Hip Arthroplasty Jon-Peter Meckel

Total hip arthroplasty (THA) is becoming more and more common in the US as people continue to live longer and more active lives. The main reason that a THA is required is due to the “wear and tear” affliction of osteoarthritis, which in the year 2000 had at least 3% of the population over 30 showing symptoms. A revitalized approach to THA is the direct anterior approach, or Smith-Petersen approach, which limits the amount of musculature affected by the surgery and creates a very stable joint …

Beach Wheelchair Project, Rory Aronson, Joshua Marcum, Samuel Coyne, Alex Hayes, Alexa Colburn, Max Hessel, Benedikt Strauss, Marvin Rimmele, Marco Pietsch

Mechanical Engineering

The Beach Wheelchair, Sandcrawler, is a machine intended to help give people with disabilities the full beach experience. The non-profit organization Bridge II Sports sponsored this project, and tasked us with developing the design and fabricating a prototype. This chair has several features including a linkage mechanism that raises and lowers a chair relative to an external frame, hand crank drive with Gates Carbondrive belt and sprockets, buoyant Wheeleez balloon tires, and much more.

Evaluation Of Thermophile Algae In Horizontal Photo-Bioreactor, Olivier Schmied

BioResource and Agricultural Engineering

No abstract provided.

Evaluation Of Corrosion Properties Of Proprietary Metal Alloy Stents For In-Vivo Use, Michael David Bremner

Materials Engineering

To assess corrosion rates of metal alloy bio-absorbable stents an experimental set-up was designed to mimic the coronary artery environment. The artery was modeled using 4mm diameter Tecoflex tubing and the metal alloy stents were inserted into the tubing using a catheter. As is the case in cardiac surgery, the catheter with the stent and a microballoon were maneuvered to the desired position. The microballoon was then slowly inflated to expand the stent and compress it against the tubing walls. The catheter and microballoon were then withdrawn. A circulating pump system was set up to cycle fetal bovine serum (FBS) …

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, …

The Fabrication & Characterization Of An Electrokinetic Microfluidic Pump From Su-8, A Negative Epoxy-Based Photoresist, Nash Anderson

Master's Theses

Microfluidics refers to manipulation, precise control, and behavior of fluids at the micro and nanoliter scales. It has entered the realm of science as a way to precisely measure or mix small amounts of fluid to perform highly controlled reactions. Glass and polydimethylsiloxane (PDMS) are common materials used to create microfluidic devices; however, glass is difficult to process and PDMS is relatively hydrophobic. In this study, SU-8, an epoxy based (negative) photoresist was used to create various electrokinetic microfluidic chips. SU-8 is commonly used in microelectromechanical design. Spin coating of various SU-8 formulations allows for 1 μm to 100 μm …

Edwards Lifesciences - Skirt To Frame Attachment Manufacturing Aid, Samuel Joda, Cesar Grimaldo, Patrick Hutchinson

Mechanical Engineering

No abstract provided.

Stent Graft Blush, Vanessa Barrett, Thomas Matzinger, Mike Morelli

Mechanical Engineering

In order to better understand Type IV endoleaks (“blush”), the Cal Poly Senior Project team GraftTest has developed a blush evaluation system able to mimic several of the aorta’s environmental parameters. Capable of both pressure and flow rate control, this bench top system accommodates Medtronic’s wide range of abdominal and thoracic aortic stent grafts. Having researched endoleaks, stent grafts, and numerous other factors affecting stent graft blush, a system was developed with the aim of assessing and comparing the performance of Medtronic’s stent grafts with regard to blush. Furthermore, this system has been designed to provide reliable and repeatable results …

Microcapsule Containing Lactic Acid Bacteria For Treatment Of Peptic Ulcers, Brandon Jerome Hinkel

Master's Theses

Probiotics are marketed throughout the world to promote the health of the consumer by improving the microorganisms that normally occur in the intestinal tract (Tannock, 1997). It has also been suggested that probiotics can prevent pathogen infections by adhering to the intestinal mucosa (Lee, Lim, Teng, Ouwehand, Tuomola, & Salminen, 2000). While probiotics can be delivered to the infected areas in multiple fashions, microencapsulation is a newer form of delivering probiotics straight to the infected area. A whey protein microcapsule is thought to protect the probiotics from stomach acid and delivers the treatment to the affected area. To ensure this …

Evaluation Of The Anterior Talofibular And Calcaneofibular Ligament In Relation To Supination Ankle Sprains, Peter Tran

Biomedical Engineering

Ankle injuries have always posed an issue to a number of athletes. Sports that involve running and jumping accumulate about 25% of injuries correlating to ankle sprains. In most ankle sprains the inversion (supination) of the ankle cause damage to lateral ligaments. The two most common lateral ligaments to experience damage are the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments. The methods of taping and ankle braces have allowed athletes to prevent recurring sprains from occurring. However, sprains can still occur even when one or both methods are applied. The purpose of each method is to restrict the range of …

Guidance System, Kayaking For The Visually Impaired, D. Ryan Kirtland, Ryan Phife, William Gardner, Amy Johnson

Biomedical Engineering

Quality Life Plus is working with Team River Runner to develop an assistive guidance system for veterans who want to remain active by kayaking, after sustaining an injury that impairs vision. This system allows these veterans to complete a slalom speed race independent of a personal guide in the water. The system incorporates 3 stations that each contain a speaker connected to a microcontroller system covered by a Pelican Case on a custom made buoy. During the slalom race, a kayaker will travel from shore towards buoy #1 as it omits sound from the speaker. As the kayaker moves around …

Shelf Life Study Of Electrospun Plga Copolymers, Sean Youra, Nick Hudson

Biomedical Engineering

Poly(lactic-co-glycolic acid) (PLGA) is one of the most commonly used copolymers for electrospinning in tissue engineering applications. However, most research has not focused on the copolymer itself in regards to how long it can be used effectively and if varying the concentrations of polylactic acid (PLA) and polyglycolic acid (PGA) affect the resulting properties. Electrospinning is the method we use to create the three-dimensional constructs, or “scaffolds”, for the blood vessel mimic (BVM) in the tissue engineering lab. The aim of our project was to investigate if the morphology and mechanical properties of the scaffolds changed over time when they …

Effect Of Oral Lipids On Blood Glucose, Tyler R. Knisley

Biomedical Engineering

Diabetes mellitus is a disease in which insulin hormone is ineffective or no longer produced. Multiple pathophysiologies can cause either insulin dependent diabetes mellitus (IDDM) or insulin independent diabetes mellitus (IIDM), which can lead to chronic hyperglycemia and an array of short and long term health risks. Prior research has shown that IDDM patients have dyslipidemia, and experiments infusing lipids directly into the blood result in heightened insulin resistance. The hypothesis that dyslipidemia increases insulin resistance was tested by performing oral glucose tolerance tests across three treatment conditions. Participants were nondiabetic college-aged students. Data from a control group was gathered …

Analysis Of Acetabular Cup Orientation Effects On Stress Shielding In Total Hip Replacements Using Finite Element Methods, Brogan Mcguire, Jennifer Gemkow, Brad Gausewitz, Alex Georges

Biomedical Engineering

Improper positioning of the acetabular cup has been shown to contribute to issues such as high wear rates and dislocations in total hip replacements. The differences in contact mechanics due to varying orientation of the acetabular cup may also significantly affect strain distribution in the femur. This study examined these effects of acetabular orientation changes and their contribution to stress shielding using finite element analysis. A solid model of a cementless total hip implant was obtained using 3D point scanning and implanted virtually into a femur solid model. The implanted femur model was imported into ABAQUS and loaded with a …

A Mouse Model Of Aortic Endothelial Denudation And Neointimal Formation, Ashkon C. Nehzati

Biomedical Engineering

More than 385,000 people die from coronary heart disease (CHD) annually and treatment costs $108.9 billion each year including the cost of health care services, medications, and lost productivity. CHD decreases heart function by limiting oxygen and nutrient transport carried through the coronary arteries. A complete block to the coronary arteries causes a myocardial infarction in response to an elimination of blood supply to cardiomyocytes. Partial occlusion results in insufficient blood supply to cardiomyocytes, producing myocardial ischemia and angina, which are usually treated with intravascular stents deployed percutaneously, before myocardial infarction occurs. Stents are the most common ways to expand …

The Effect Of A Triphasic Pulse On Scs To Icd Crosstalk, Ryan James Wensley

Master's Theses

It is a known problem that a Spinal Cord Stimulator (SCS) can interact with an Implantable Cardioverter Defibrillator (ICD) when both devices are implanted in the same patient. Interactions between the SCS and ICD can cause inappropriate therapy which can be harmful to the patient. While ICD devices have a distinct narrowband sensing bandwidth, the pulse configurations that current SCS devices deliver were not designed with this frequency region in mind. In this thesis, I recommend a new pulse configuration for SCS devices that will minimize the interaction between the two devices. I produce a theoretical equation for each pulse …

Design And Development Of A Stair Ascension Assistive Device For Transfemoral Amputees, Casey Michael Barbarino

Master's Theses

Transfemoral amputees around the world experience increased difficulty in climbing stairs due to lack of muscle, balance, and other factors. The loss of a lower limb greatly diminishes the amount of natural force generation provided that is necessary to propel oneself up stairs. This study investigated possible solutions to the problem of stair ascension for transfemoral amputees by the means of designing and developing an externally attachable device to a prosthesis. The number of amputations from military service has greatly increased since 2008, which shows there is a clear need for assistive devices (Wenke, Krueger, & Ficke, 2012). With the …

Matrix Remodeling Accompanies In Vitro Articular Cartilage Spherical Shaping, Nathan Thomas Balcom

Master's Theses

Introduction: Articular cartilage (AC) is a low friction load bearing material found in synovial joints. The natural repair of damaged tissue is difficult and often requires surgical intervention. With large defects it becomes necessary to match the original tissue geometry. We hypothesized that localized collagen (COL) and/or proteoglycan (PG) remodeling occurs during AC spherical reshaping. The objective of this study was to determine the presence, magnitude and depth dependence of COL and PG remodeling that accompanies AC reshaping. Methods: Full thickness AC blocks (7x7 mm² surface area) were harvested from the ridges of the patellofemoral groove of immature (1-3 …

Computational Modeling To Evaluate Helical Electrode Designs For Use In Vagus Nerve Stimulation, Anthony W. Cowley

Master's Theses

An estimated 0.5% of world’s population has been diagnosed with epilepsy. Of these patients 20-30% will be unable to achieve seizure control with anti-epileptic drugs. Vagus nerve stimulation (VNS) may be an appropriate treatment option for some patients with pharmaceutically refractory, partial-onset seizures.

VNS therapy uses a helical electrode to interface between the implantable pulse generator and the vagus nerve. While there have been several studies related to the mechanical and electrical safety of such electrodes, little work has been done toward understanding the effectiveness of the helical electrode in nerve stimulation. A better understanding of the voltage field and …