Biomedical Engineering and Bioengineering Commons^™

Mammary Epithelial Cell Growth On A Three-Dimensional Scaffold In An Operating Bioreactor, Melissa Marie Davalle

Master's Theses

Mammary epithelial cells are highly efficient secreting cells. With genetic engineering, the uses of these cells could be endless. Research is being conducted on these cells to determine their full potential to the biotech industry.

This paper investigates whether bovine epithelial mammary cells can survive in glutaraldehyde-treated gelatin tubes in an operating bioreactor. Many bioreactors were developed and tested to suit the needs of the cells. Procedures were created and carried out to ensure sterility of the bioreactors. Bovine mammary epithelial cells were implanted in the bioreactors and samples of their growth were taken over time.

Investigation Of A Simulated Annealing Cooling Schedule Used To Optimize The Estimation Of The Fiber Diameter Distribution In A Peripheral Nerve Trunk, Arya Vigeh

Master's Theses

In previous studies it was determined that the fiber diameter distribution in a peripheral nerve could be estimated by a simulation technique known as group delay. These results could be further improved using a combinatorial optimization algorithm called simulated annealing. This paper explores the structure and behavior of simulated annealing for the application of optimizing the group delay estimated fiber diameter distribution. Specifically, a set of parameters known as the cooling schedule is investigated to determine its effectiveness in the optimization process.

Simulated annealing is a technique for finding the global minimum (or maximum) of a cost function which may …

Design And Development Of Two Test Fixtures To Test The Longitudinal And Transverse Tensile Properties Of Small Diameter Tubular Polymers, Carolyn Berry

Master's Theses

Hundreds of thousands of vascular bypass grafts are implanted in the United States every year, but there has yet to be an ideal graft material to substitute for one’s own autologous vessel. Many synthetic materials have been shown to be successful vessel replacements; however, none have been proven to exhibit the same mechanical properties as native vessels, one of the most important criteria in selecting a vascular graft material. Part of this issue is due to the fact that, currently, there is no “gold standard” for testing the longitudinal and transverse tensile properties of small diameter tubular materials. While there …

Polymeric Splint And Rapid-Setting Polyurethane, Lanny Griffin, Dane Robert Jones

Biomedical Engineering

A splint includes a first container capable of being wrapped about an item to be supported and a second container capable of containing a multiple part mixture during a mixing operation. The second container being capable of delivering the mixture into the first container, wherein the mixture hardens to form a support structure. A method for using the splint is also disclosed.

A Study Of Osteocyte Apoptosis By Region And Quadrant In Murine Cortical Bone, Jessica Kristen Chan

Master's Theses

ABSTRACT

A Study of Osteocyte Apoptosis by Region and Quadrant in Murine Cortical Bone

Jessica Kristen Chan

Osteocytes undergo apoptosis to spatially and temporally initiate bone remodeling.  This study investigates the distribution of apoptotic osteocytes within different quadrants and regions of cortical bone and compares the frequency of osteocyte apoptosis to regional factors associated with bone remodeling.  Specifically, the quantity of apoptosis was compared to levels of the bone morphagenic protein antagonists noggin and gremlin.  Samples of unloaded right tibial bone obtained from C57/Bl/6 mice underwent TUNEL staining for apoptotic osteocytes and were counterstained with methyl green to detect osteocyte …

Universal Engineering Programmer – An In-House Development Tool For Developing And Testing Implantable Medical Devices In St. Jude Medical, Khoa Tat Do

Master's Theses

During development and testing of the functionality of the pacemaker and defibrillator device, engineers in the St. Jude Medical Cardiac Rhythm Management Division use an in-house development tool called Universal Engineering Programmer (UEP) to ensure the device functions as expected, before it can be used to test on an animal or a human during the implantation process.  In addition, some applications of UEP are incorporated into the official releases of the device product.  UEP has been developed and used by engineers across departments in the St. Jude Medical Cardiac Rhythm Management Division (CRMD).  This thesis covers the flexible and reusable …

The Biomechanics Of Varied Proximal Locking Screw Configurations In A Synthetic Model Of Proximal Third Tibial Fracture Fixation, Philip R. Wolinsky, Douglas Dennis, Brett D. Crist, Shane Curtiss, Scott J. Hazelwood

Biomedical Engineering

Objective: To determine if 1) angularly stable devices created by compressing (‘‘locking’’) proximal locking screws to intramedullary nails using end caps or compression screws or 2) increasing the number of proximal screws from two to three increases the stiffness of intramedullary constructs that stabilize proximal third tibia fractures in a nonosteopenic bone model.

Methods: Four proximal locking screw configurations were examined in a synthetic composite tibia model with a 2-cm gap simulating a comminuted proximal third tibia fracture with no bony contact: 1) two proximal screws not compressed to the nail; 2) one of two proximal screws compressed to …

Laser Etched Pmma Microfluidic Chip Design And Manufacture With Applications In Capillary Zone Electrophoresis, Evan Allen Barbre

Master's Theses

This thesis encompasses a feasibility study of using low-cost materials to manufacture microfluidic chips that can perform the same functions as chips manufactured using traditional methods within an acceptable range of efficiency of chips created with more exotic methods and materials. The major parts of the project are the selection and characterization of the fabrication methods for creating the channels for fluid flow, the methods for sealing the channels to create a usable chip and the electrophoretic separations of carboxylated microspheres of different potentials. In this work we seek to answer the question if laser-etched PMMA microfluidic chips are comparable …

Sar Map Of Gel Phantom In A 64mhz Mri Birdcage By Fiber-Optic Thermometry And Fdtd Simulation, Chirag Mukesh Patel

Master's Theses

As implantable medical devices are being used more often to treat medical problems for which pharmaceuticals don’t suffice, it is important to understand their interactions with commonly used medical modalities. The interactions between medical implants and Magnetic Resonance Imaging machines have proven to be a risk for patients with implants.

Implanted medical devices with elongated metallic components can create harmful levels of local heating in a Magnetic Resonance Imaging (MRI) environment [1]. The heating of a biological medium under MRI is monitored via the Specific Absorption Rate (SAR). SAR, defined as power absorbed per unit mass (W/kg), can be calculated …

Investigation Of Pmma Cement Penetration In Prepared Femoral Heads With A Longitudinal Slot For Hip Resurfacing Arthroplasty, Scott Snyder

Biomedical Engineering

Hip resurfacing arthroplasty is becoming increasingly popular in younger, active patients due to its preservation of natural biomechanics. Failure of these implants can be very traumatic and potentially life threatening. The role of cement penetration in early implant failure is not yet known, and must be investigated. This study specifically investigates the effects of a 5mm by 5mm longitudinal channel on cement penetration into the femoral head. High-density open-cell reticulated vitreous carbon foam cylinders and Huntsman Pro-cast® 20 implants based on the Birmingham Hip Resurfacing implant were used. It was determined cement penetration was increased in the area immediately surrounding …

The Effect Of Cox-2 Specific Inhibition On Direct Fracture Healing In The Rabbit Tibia, David J. Hak, Kurt S. Schulz, Behrang Khoie, Scott J. Hazelwood

Biomedical Engineering

Objective: The purpose of this study was to evaluate the effect of Cox-2 administration on direct (primary) fracture healing.

Methods: A transverse tibial osteotomy was created in adult male rabbits and rigidly fixed in compression using a 2.7-mm dynamic compression plate. Animals were randomized to receive either rofecoxib (12.5 mg orally per day) or placebo. Animals were killed at 4 weeks and fracture healing assessed by mechanical testing.

Results: There were no significant differences between the control and Cox-2 treated animals in terms of mechanical strength at 4 weeks. There was a high complication rate of peri-implant fractures …

Arteriogenesis And Ischemia Impair Functional Vasodilation In Resistance Arteries, Trevor Cardinal, Joseph S. Zhu, Kyle R. Struthers, Thomas J. Kesler, Matthew D. Yocum

Biomedical Engineering

No abstract provided.

Characterization Of Bioreactor System For Tissue Engineered Blood Vessels, Kasim Shah

Biomedical Engineering

No abstract provided.

The Development And Validation Of A Finite Element Model Of A Canine Rib For Use With A Bone Remodeling Algorithm., Scott J. Sylliaasen

Master's Theses

Studies are currently being performed to determine the effects of bisphosphonate treatments on the structure and density of bone tissue. One of the pathways for gaining a better understanding of the effects of this and other treatments involves creating a computer simulation. Theory suggests that bone tissue structure and density are directly related to the manner in which the tissue is loaded. Remodeling is the process in which bone tissue is resorbed in areas of low stress distributions, and generated in areas of high stress distributions. Previous studies have utilized numerical methods and finite element methods to predict bone structure …

Assessment Of Morphology And Hemodynamics In Normal And Remodeled Microvasculature With Parameter Sensitivity Analysis, Shilpi Ghosh

Master's Theses

The goal of this study was to compare the morphological and hemodynamic characteristics of normal and remodeled vascular networks in the mouse gracilis muscle. To this end, previously developed models to assess flows and vascular branching were used to assess the normal and remodeled microcirculatory networks. The analysis revealed that the average individual vessel flow rates for vessels of similar caliber and total volumetric flow rates in the networks do not change for vessels of the same caliber after remodeling. Connectivity changes and average diameters primarily change in the larger arterioles after remodeling. A few correlations could be made between …

An Investigation Of Process Parameters To Optimize The Fiber Diameter Of Electrospun Vascular Scaffolds Through Experimental Design, Steffi Wong

Biomedical Engineering

No abstract provided.

Characterization And Analysis Techniques Of A Dynamic In Vitro Blood-Brain Barrier Model, Ryan Everett Woodhouse

Biomedical Engineering

The blood-brain barrier (BBB) is responsible for maintaining the sensitive environment required by the brain. Although the BBB is necessary for proper functioning of the brain, it acts as an obstacle for doctors attempting to treat neurological disease. For a drug to act upon the brain, it must first pass through the discriminating BBB. For this reason, much research has been performed in recent years in order to create an in vitro model of the BBB on which drugs targeted for the central nervous system may be tested. The main goal of this project is to create an in vitro …

Can Spr Be Used To Interrogate The Double Layer Of Nacl, Brandon Kawula

Biomedical Engineering

Solutions of reagent grade salt .1, .01, .001, .0001, .00001M were run through a SPR to see if SPR had enough resolution to detect the formation of the electric double layer. We found that NaCl did in fact return a detectable signal. The signal shape seems to depend on concentration. While more study may need to be done to get definite information it looks like SPR can interrogate the double layer.

Differential Regulation Of Immature Articular Cartilage Compressive Moduli And Poisson's Ratios By In Vitro Stimulation With Igf-1 And Tgf-Β1, Gregory M. Williams, Kristin J. Dills, Christian R. Flores, Michael E. Stender, Kevin M. Stewart, Lauren M. Nelson, Albert C. Chen, Koichi Masuda, Scott J. Hazelwood, Stephen M. Klisch, Robert L. Sah

Biomedical Engineering

Mechanisms of articular cartilage growth and maturation have been elucidated by studying composition-function dynamics during in vivo development and in vitro culture with stimuli such as insulin-like growth factor-1 (IGF-1) and transforming growth factor-beta 1 (TGF-β1). This study tested the hypothesis that IGF-1 and TGF-β1 regulate immature cartilage compressive moduli and Poisson’s ratios in a manner consistent with known effects on tensile properties. Bovine calf articular cartilage from superficial-articular (S) and middle-growth (M) regions were analyzed fresh or following culture in medium with IGF-1 or TGF-β1. Mechanical properties in confined (CC) and unconfined (UCC) compression, cartilage matrix composition, and explant …

Multi-Frequency Processing For Lumen Enhancement With Wideband Intravascular Ultrasound, Rory A. Carrillo

Master's Theses

The application of high frequency ultrasound is the key to higher resolution intravascular ultrasound (IVUS) images. The need to further improve the IVUS spatial resolution may drive the transducer center frequency even higher than the current 40 MHz range. However, increasing the center frequency may be challenging as it leads to stronger scattering echoes from blood. The high level of blood scattering echoes may obscure the arterial lumen and make image interpretation difficult. Blood backscatter levels increase with transmission center frequency at a much greater rate compared to arterial tissue. These different frequency dependencies provide a potential method to distinguish …

St. Jude Medical: Enhanced Mics (Emics), Devanshi Shah

Master's Theses

Heart disease is one of the most prevalent diseases in the world. The survival chances for patients with ventricular fibrillation/ventricular tachycardia reduces significantly as time passes without treatment and even after getting timely treatment recurring episode are common. These patients can benefit from an Implantable Cardioverter Defibrillator (ICD) which can monitor heart rhythm and provide immediate treatment. Due to the ever changing physical conditions and disease progression, the ICD needs to collect diagnostic data as well as support programming by the physician. The ICD uses inductive telemetry and radio-frequency telemetry for the communication with the external devices such as a …

Integration Of Microfluidics With Surface Plasmon Resonance, Scott B. Fratzke

Master's Theses

This thesis successfully integrates laminate microfluidic devices with an analytic Surface Plasmon Resonance (SPR) instrument. Integration was accomplished at low-cost using materials such as polydimethylsiloxane (PDMS), Poly(methyl methacrylate) (PMMA), Tygon tubing, and a 3-way stopcock. The main components of this thesis are the design and fabrication of the low-cost, in-house fluidics that can integrate with upstream microfluidics and the validation of the in-house fluidics using the Biosensing Instruments BI-2000 SPR instrument. The low-cost fluidics was designed and fabricated “in-house” using a novel investment casting technique that required the use of laser cutting technology to make a master cast, and candle …

St. Jude Medical: An Object-Oriented Software Architecture For Embedded And Real-Time Medical Devices, Atila Amiri

Master's Theses

Medical devices used for surgical or therapeutic purposes require a high degree of safety and effectiveness. Software is critical component of many such medical devices. The software architecture of a system defines organizational structure and the runtime characteristic of the application used to control the operation of the system and provides a set of frameworks that are used to develop that. As such, the design of software architecture is a critical element in achieving the intended functionality, performance, and safety requirements of a medical device. This architecture uses object-oriented design techniques, which model the underlying system as a set of …

Immunohistochemical Mapping Of Hypoxia In Ischemic Mouse Hindlimb Skeletal Muscle, Emily Deckert

Biomedical Engineering

The study of blood vessel growth and remodeling is a complex endeavor. Hypoxia, the lack of oxygen in a tissue, is known to stimulate angiogenesis (the growth of new blood vessels), and have little effect on arteriogenesis (the enlargement of existing blood vessels). However, the role of hypoxia in vessel function is unknown, but may be determined using the results and methods developed in this experiment.

Supplied by the bloodstream, oxygen is required by all cells and tissues to remain healthy. If the bloodstream supplying a certain tissue with blood is disrupted, the tissue becomes ischemic, often leading to hypoxia. …

Implementation Of Physiologic Pressure Conditions In A Blood Vessel Mimic Bioreactor System, Kevin Mark Okarski

Master's Theses

ABSTRACT

Implementation of Physiologic Pressure Conditions in a Blood Vessel Mimic Bioreactor System

Kevin Mark Okarski

Tissue engineering has traditionally been pursued as a therapeutic science intended for restoring or replacing diseased or damaged biologic tissues or organs. Cal Poly’s Blood Vessel Mimic Laboratory is developing a novel application of tissue engineering as a tool for the preclinical evaluation of intravascular devices. The blood vessel mimic (BVM) system has been previously used to assess the tissue response to deployed stents, but under non-physiologic conditions. Since then, efforts have been made to improve the vessel and bioreactor’s ability to emulate in …

Development Towards A Protocol To Test For The Creation Of A “Diabetic” Environment In A Blood Vessel Mimic, Kaitlyn Kirk, Development Towards A Protocol To Test For The Creation Of A “Diabetic” Environment In A Blood Vessel Mimic

Biomedical Engineering

Diabetes mellitus affects a huge proportion of people; about 6% of the population in the US had diabetes in 2007 (16). Diabetes promotes dyslipidemia, an imbalance in the circulating levels of lipids and lipoproteins, and diabetes is one of the leading risk factors for coronary artery and peripheral vascular diseases (11, 51, 52).  There are two types of diabetes; type 1 diabetes accounts for about 10% of diagnosed cases and type 2 accounts for about 90% (11).  Diabetic patients react differently to stents and there is a great need to enhance the treatment.  The goal of this project was, and …

Frontal Plane Humeral Elevation Effects On The Pullout Strength Of Suture Anchors Used In Rotator Cuff Repair, Peter Joshua Larson

Master's Theses

The rotator cuff offers the stabilizing forces necessary for fine arm movement. The most common injury to the rotator cuff is the partial or full thickness tear of the supraspinatus tendon, which attaches the humerus to the scapula on the superior side, due to an acute or chronic injury. These injuries account for more than 4.5 million physician visits per year. Depending on the degree of tear, arthroscopic surgery may be needed to reattach the torn tendon to the humeral head. The current preferred method of surgery involves the insertion of a suture anchor into the humeral head that ties …

Effects Of Reamer-Femoral Component Offset On Cement Mantle Penetration In Hip Resurfacing Arthroplasty, Mark Lloyd Paulick

Master's Theses

Hip resurfacing arthroplasty has changed the treatment of end stage arthritis without severe deformity for young, active adults. Presently, there are varying clinical approaches to implant design selection and cementation techniques. The purpose of this project is to determine what amount of reamer-femoral component offset allows for the best cement penetration into the femoral head.

Rapid prototyped femoral component models were produced with reamer femoral component offsets of 0.0 mm, 0.5 mm, and 1.0 mm. After implantation onto models of reamed femoral heads made from high-density open-cell reticulated carbon foam, cement penetration was assessed from cross-sections of the foam-implant unit. …

Finite Element Modeling Of Icd Lead Silicone Soft-Tips, Jose J. Lepe

Master's Theses

Although highly underutilized by the medical device industry, Finite Element Analysis (FEA) in the development of new technologies is gaining popularity as regulatory bodies such as the Food and Drug Administration (FDA) begin to require additional proof of safety through scientific methods. Non-linear FEA allows engineers to realistically simulate the mechanical behavior of implants as seen in the in-vitro, or in some cases, the in-vivo configurations. The work presented in this report investigates how computational methods can be used to simulate the interaction of a St. Jude Medical silicone soft-tip as it passes through a Peel-Away Sheath (i.e. introducer). In …

Locked Plate Fixation Of Osteoporotic Humeral Shaft Fractures: Are Two Locking Screws Per Segment Enough?, David J. Hak, Peter Althausen, S J. Hazelwood

Biomedical Engineering

Objective: The purpose of this study was to compare the biomechanical behavior of using two versus three locking screws per bone segment in a cadaveric humerus fracture gap model.

Methods: Six matched pairs of elderly osteoporotic fresh–frozen human cadaveric humerii were used. An eight-hole locking compression plate was placed posteriorly on the humeral shaft and secured with either four or six bicortical locking screws. A 5-mm middiaphyseal gap osteotomy was created to simulate a comminuted fracture without bony contact. Specimens were tested in offset axial compression, four-point anteroposterior bending, four-point medial– lateral bending, and torsion. After the initial testing in …