Biological Engineering Commons^™

Development Of An Angiogenic Tissue-On-A-Chip Microenvironment, Eric Stuehr

Master's Theses

Preclinical testing is necessary to investigate the safety and efficacy of novel therapeutics before moving to clinical trials, yet approximately 90% of these therapies fail once tested in humans. This has led to increased interest in developing robust preclinical models that accurately mimic the complex human in vivo physiology. Microfluidic devices that can introduce dynamic conditions to 3D cell/organoid cultures, also known as tissue-on-a-chip, have emerged as physiologically relevant in vitro preclinical models that can achieve high throughput screening of therapeutics. The research presented here aimed to develop an angiogenic environment within a novel microfluidic device to stimulate formation of …

Hypoxic Incubation Chamber, Simone Lisette Helfrich, Makenzie Nicole Jones

Biomedical Engineering: Graduate Reports and Projects

This paper describes the design, manufacturing, and testing of a novel controllable hypoxic incubator with fully functional oxygen gas control and temperature control in a humid environment. On the current market, a majority of the few hypoxic incubators use pre-mixed gas that does not offer precise control over gas concentration. The objective for this project was to create a chamber that allows the user to set the O2 concentration to varying set points of % O2 while maintaining the chamber at a constant body temperature, CO2 level, humidity, and sterility. To start the project, multiple concepts were developed for the …

Functionality Of The Gracilis Collateral Is Impaired Following Arteriogenesis And Cell Transplantation, Ada A. Tadeo

Biomedical Engineering

Peripheral Arterial Disease involves narrowed arteries, reducing blood flow to limbs. Increasing blood flow to those extremities is possible by redirecting the blood to flow through natural bypasses (i.e. collateral arteries), which can enlarge via arteriogenesis to maintain blood supply once the prominent arteries have become occluded. This study aims to investigate how arteriogenesis affects collateral function, if myoblast transplantation can stimulate collateral growth, and how that in turn may affect collateral function. Femoral artery ligation was performed to mimic the blockage that occurs in patients with ischemic diseases on lean mice and mice with diet induced obesity (DIO). A …

Bone And Cartilage Compression Simulator, Karoline M. Wucherer, Benjamin A. Parmentier, Thomasina E. Hinkle

Biomedical Engineering

A device was developed that delivers mechanical loads to bone and soft tissue samples under physiological conditions to aid in the research of tissue engineering bone and cartilage. To begin the design process, a Network Diagram and Gantt Chart were produced to create a general timeline for the project to follow. This allowed us to measure our progress and determine what effects (if any) delays could have on our project.

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 …

Adaptive Laboratory Evolution Of Scenedesmus Obliquus For Increased Carbohydrate Content And Biomass Productivity, Nahel Ali

Master's Theses

The economics of microalgal bioproduct commercialization would benefit from increased accumulation of energy storage compounds, such as carbohydrates and lipids, and increased biomass productivity. This thesis explores two adaptive laboratory evolution strategies for improving Scenedesmus obliquus: single UV-mutagenesis and low light cultivation at a high dilution rate to produce cultigens with greater carbohydrate content and iterative UV-mutagenesis and selection under outdoor conditions in a raceway pond at a high dilution rate to increase biomass productivity.

Two cultigens were generated with the goal of increased carbohydrate content: K5 and K7. Both were mutagenized for 5 seconds and cultivated in 50-mL …

Development Of A Robust Methodology To Obtain And Assess Myogenic Precursor Cells For Their Use In Regenerative Therapies, Ricardo Lasa

Master's Theses

Peripheral arterial occlusive disease (PAOD) is characterized by buildup of atherosclerotic plaque in peripheral arteries that leads to an occlusion that can interrupt the supply of blood to the peripheral tissue, causing downstream tissue ischemia/hypoxia. PAOD is estimated to affect over 200 million patients worldwide. Current surgical revascularization treatments can be effective in about half of the patient population, leading to a significant number of patients with no treatment options beyond pharmacological intervention and lifestyle modification. The decrease in blood flow downstream of the occlusion leads to increased blood pressure gradient in the microvasculature, specifically in vessels that connect arterial …

Gesea Biosciences - Core Shell Pellet Manufacturing Device, Claire Edelman, Maria Medrano, Rachel Longoria

Biomedical Engineering

No abstract provided.

Methods To Increase Algae Biomass Productivity In Raceway Pond Monocultures, Ryan S. Anderson

Master's Theses

The economics of algae biofuels and bioproducts would be improved by increased biomass productivity. Two studies on this potential are described in this thesis – one on a locally isolated filamentous yellow-green alga and the other on a planktonic strain genetically improved via selective enrichment.

Polycultures have been viewed as productive, stable, and, in some cases, harvestable by natural bioflocculation. Local native strains might have higher productivity than culture collection strains because they are already adapted to local outdoor conditions. In this study, the filamentous yellow-green alga Tribonema minus was isolated from a local volunteer polyculture. Its productivity as a …

Blood Glucose Predictor, Jessica Patterson

Electrical Engineering

For my senior project, I perform data analysis using statistical methods to determine body metrics that correlate with blood glucose levels. Working with Dr. Tina Smilkstein, I take repeat measurements from 6 different volunteers to establish trends in bodily metric data. The data taken includes weight, body fat, pulse rate, VO2, blood glucose, blood pressure, hours slept, and quality of sleep. Using these values, I use the program MiniTab to view results.

A few examples of correlations with blood glucose found in this project are:

• Systolic blood pressure for females had a regression line of 124.0 -0.3366*Blood Pressure. This indicates …

Mechanisms Of Reduced Vascular Tone Following Arteriogenesis Induced By Femoral Artery Ligation, Christopher Hatch

Biomedical Engineering

The presence of a developed, native collateral network can decrease the severity of ischemic injury proceeding arterial occlusion. The collateral network must under arteriogenesis to enlarge and increase blood flow to the ischemic region. Although there has been tremendous effort attempting to understand the mechanisms of arteriogenesis, no therapies have been successful in improving patient outcome. To better understand the mechanisms involved in arteriogenesis, the effect of nitric oxide production, myogenic tone, and a-adrenergic receptors were evaluated as these have been identified as playing an important role in vascular injury. Arteriogenesis was induced by ligating the femoral artery between the …

Fluid Delivery System For A Cell Culture On A Microfluidic Chip, Austin J. Roeder, Colleen A. Richards, Emily A. Matteson

Biomedical Engineering

This project report provides a description of the progress made in the development of a fluid delivery system for a microfluidic cell culture on a chip. The system is intended to be used in a humidified incubator in a university laboratory and the fluid delivery system is required to exist and operate within that incubator for extended periods of time. Therefore, the system will be gravity-driven and contain no electronic components. The key specification of the system is to provide fluid flow at a constant velocity.

After manufacturing and testing the device, all specifications were met except for the fluid …

Microfluidic Electrical Impedance Spectroscopy, John J. Foley

Master's Theses

The goal of this study is to design and manufacture a microfluidic device capable of measuring changes in impedance valuesof microfluidic cell cultures. Tocharacterize this, an interdigitated array of electrodes was patterned over glass, where it was then bonded to a series of fluidic networks created in PDMS via soft lithography. The device measured ethanol impedance initially to show that values remain consistent over time. Impedance values of water and 1% wt. saltwater were compared to show that the device is able to detect changes in impedance, with up to a 60% reduction in electrical impedance in saltwater. Cells were …

Comparative Analysis Of Physiological Measurements And Environmental Metrics On Predicting Heat Stress Related Events, Mckenzie Lee Barlow

Master's Theses

Exposure to high heat and humidity can lead to serious health risks, including heat exhaustion and heat stroke. Wet Bulb Globe Temperature (WBGT) and heat index have historically been used to predict heat stress events, but individualized factors are not included in the measurement. It has been shown that there is a relationship between cardiovascular measurements and heat stress, which could be used to measure heat stress risk on an individual level. Research has been done to find relationships between cardiovascular metrics in a workplace environment, however the study did not include the use of a controlled environment as a …

Computer-Aided Diagnoses (Cad) System: An Artificial Neural Network Approach To Mri Analysis And Diagnosis Of Alzheimer's Disease (Ad), Berizohar Padilla Cerezo

Master's Theses

Alzheimer’s disease (AD) is a chronic and progressive, irreversible syndrome that deteriorates the cognitive functions. Official death certificates of 2013 reported 84,767 deaths from Alzheimer’s disease, making it the 6th leading cause of death in the United States. The rate of AD is estimated to double by 2050. The neurodegeneration of AD occurs decades before symptoms of dementia are evident. Therefore, having an efficient methodology for the early and proper diagnosis can lead to more effective treatments.

Neuroimaging techniques such as magnetic resonance imaging (MRI) can detect changes in the brain of living subjects. Moreover, medical imaging techniques are the …

Influence Of Fibroblasts On Functional Arteriogenesis In A Murine Chronic Hindlimb Ischemia Model, Ashli A. Santos

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) occurs when there is a narrowing or blockage – usually a buildup of plaque - within the arteries that reduces blood flow to tissues which can chronic ischemia. As with most diseases, early detection and proactive treatment are important to maximize prognosis. Exercise effectively treats PAOD, but due to ischemic pain in the limbs, or intermittent claudication (IC), exercise can become painful and difficult. Due to the buildup of plaque, occlusions create an ischemic environment that changes the pressure distribution in collateral networks and increases the shear stress in transverse collaterals. Those two responses signal …

Development And Characterization Of Tissue Engineered Blood Vessel Mimics Under "Diabetic" Conditions, Shelby Gabrielle Kunz

Master's Theses

The development of tissue engineered blood vessel mimics for the testing of intravascular devices in vitro has been established in the Cal Poly tissue engineering lab. Due to the prevalence of cardiovascular disease in diabetic patients and minimal accessible studies regarding the interactions between diabetes and intravascular devices used to treat vascular disease, there is a need for the development of diabetic models that more accurately represents diabetic processes occurring in the blood vessels, primarily endothelial dysfunction. This thesis aimed to create a diabetic blood vessel mimic by implementing a high glucose environment for culturing human endothelial cells from healthy …

Functional Vasodilation And Vascular Reactivity In Arteriolar Collaterals In The Spinotrapezius Of Males And Females, Britta C. Nelson

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) occurs when there is narrowing or blockage of the peripheral arteries that carry blood to the extremities, most commonly the legs. The most common symptom of PAOD is intermittent claudication, or ischemic pain during exercise. Women with PAOD experience a greater extremity functional impairment than men. Since impaired vasodilation might cause the ischemic pain from PAOD, we should evaluate vasodilation post ligation in males and females in collateral vessels, which connect two arterial segments to maintain blood flow to an otherwise hypoxic area. First, we need to examine collateral vasodilation in unoperated male and female …

Midfield Rf Signal Detector, Dawei Zhang

Electrical Engineering

This project is part of a Master’s thesis which looks at alternative ways to measure blood glucose. The Master’s thesis uses mid-field signals in order to match impedance and therefore lose less power as they travel through flesh. The goal of this senior project is to build a receiver for those signals and give accurate RSSI (received signal strength indicator) measurements. Mid-fields were originally explored by Stanford professor Dr. Ada Poon [3] who used the signaling technique to recharge the batteries of deeply implanted devices. Devices implanted near the surface of the skin were able to have their batteries recharged …

Vascular Reactivity In Newly-Formed And Mature Arterialized Collateral Capillaries, Sara K. Hellstrom

Master's Theses

Peripheral arterial occlusive disease (PAOD) is a globally-prevalent cardiovascular disease in which atherosclerotic plaques narrow arterial lumen diameters and restrict blood flow to downstream 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. In animal models that lack collateral arterioles, capillaries that connect terminal arteriolar segments can arterialize and form functional collaterals following an ischemic event; however, in the early stages of development, vasodilation is impaired. We explored the mechanism of impaired vasodilation in arterialized collateral capillaries (ACCs) and pre-existing collaterals (PECs) by evaluating …

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 …

Smooth Muscle Cell Organization In The Stem Region Of The Gracilis Collateral Circulation, Amanda Krall

Biomedical Engineering

Many patients who suffer from the ischemic Peripheral Arterial Occlusive Disease (PAOD) experience intermittent claudication, which can be attributed to impaired vasodilation. Collateral vessels are the primary site of resistance to blood flow downstream; therefore maximizing vasodilation in collaterals is crucial for efficient circulation. Collaterals function as natural bypasses around the occluded arteries and the increase in flow into these vessels causes them to outwardly remodel into conduit vessels. However, functional vasodilation in the stem region of collateral vessels is impaired at day 7 following femoral ligation, which can be attributed to smooth muscle cell malfunction. However, the increase in …

Life Support: Long Term Storage Of Solid Waste In An Enclosed Membrane System, Emmy O. Trieu, Michael Flynn, Rocco Mancinelli

STAR Program Research Presentations

In deep space missions, maintaining life support is of the utmost priority. In such a closed system, human waste must be stored and treated. Simulated feces (ersatz) will be inoculated with microbes representing normal fecal flora, mixed with urine brine and shredded refuse of products typically used in space missions. Composting methods often use alternating layers of waste with scraps of carboniferous materials (finely shredded refuse). By preparing membrane bags with a homogenized ersatz and carboniferous refuse mixture and membrane bags with alternating layers of ersatz and carboniferous refuse, it may be possible to monitor anaerobic thermophillic digestion of the …

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.

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 …

Development Of A Protocol To Measure Gene Expression In The Mouse Tibia, Daniel Hoover

Biomedical Engineering

Numerous molecular factors active in bone tissue direct fracture repair and remodeling which can be altered by disease conditions such as Peripheral Arterial Disease (PAD) and Osteoporosis. Methods of molecular biology are commonly applied to investigate the expression and role of these molecular factors. This project presents a robust three-step protocol for examining gene expression in the mouse tibia. The protocol begins with isolating RNA from a flash frozen tibia sample. The isolated RNA is reverse transcribed into cDNA. Finally, PCR is performed to indentify expressed genes. Establishing this protocol will allow further research into the mechanisms of bone remodeling …

Enhanced Hydrocarbon Biodegradation Using Bioaugmentation With Biowish™-Aqua Fog, Michael Robert Lehrer

Master's Theses

This study was done to determine the effectiveness of a commercially available bioaugmentation product, BiOWiSH^TM-Aqua FOG, for remediating petroleum-contaminated sandy soil. Biodegradation enhancement by BiOWiSH^TM-Aqua FOG was evaluated in laboratory microcosms by directly measuring total petroleum hydrocarbon (TPH) and indirectly using respirometry. Attempts were made to enrich hydrocarbon-degrading bacteria in BiOWiSH^TM-Aqua FOG, and the resulting enrichment cultures were screened using respirometry as well. Potential hydrocarbon-degrading bacteria in BiOWiSH^TM-Aqua FOG were isolated. Experiments were performed at bench-scale using microcosm bottles containing sand contaminated with either motor oil or No. 2 diesel fuel. The …

The Characterization Of Biofilm Attachment To Metal Interfaces: Effects Of Substratum Properties, Marcel D. Mendes

Master's Theses

Bacteria are among the most abundant microorganisms on earth, and can be found in essentially every environment. When a clean surface is exposed to media containing planktonic bacteria, the bacterial cells will attach to the surface and aggregate to form what is known as a biofilm. Biofilms have been shown to negatively affect many industries including medical, industrial, and food science applications. While biofilms have been well characterized from a microbiology perspective, there has been much less research from a materials science standpoint. It is hypothesized that the material properties of the substratum (such as the micro-structure) have a significant …

Protective Effects Of Milk Phospholipids Against Uv Photodamage In Human Skin Equivalents, Zyra Achay

Master's Theses

The ultraviolet (UV) spectrum has been known to cause damage to skin in varying degrees. UVB radiation (290-320 nm) in particular, has been proven to be highly mutagenic and carcinogenic in many animal experiments compared to either UVA or UVC. The alarming rate of increase in skin cancer incidence has prompted many investigators to pursue other alternatives to sunscreens including changes in lifestyle habits and dietary consumption in order to boost our efforts in tackling this widespread disease. Previous studies employing confocal reflectance, MTT assay and histology suggest that milk phospholipids may possess protective properties against UVB-mediated damage but the …

Forward Osmosis Bag: Ground Testing The Prospect Of Using Alternative Water Sources For Drinking Water, Michaela Marie Brant, Ariella Yendler, Mona Hammoudeh, Michael T. Flynn

STAR Program Research Presentations

On the STS-135 Space Shuttle mission, to be launched July 8, 2011, a forward osmosis bag (FOB) study will be conducted. At NASA Ames this summer, the ground truth testing is being conducted for results comparisons. The FOB technology is derived from a commercial product, the X-Pack water filter. Forward osmosis operates by utilizing an established concentration gradient across a semi-permeable membrane to move water molecules from one side of the membrane to the other. This concept is exploited to harvest drinking water from grey water sources such as urine, sea water, or vehicle water. In this experiment, potassium chloride …