Biomedical Engineering and Bioengineering Commons^™

Nanosecond Stimulation And Defibrillation Of Langendorff-Perfused Rabbit Hearts, Johanna Neuber

Biomedical Engineering Theses & Dissertations

The search for novel defibrillation methodologies focuses on minimizing deposition of energy to the heart, as this is an indicator for side effects including pain and tissue death. In this work, we investigate the effect of reducing the duration of the applied shocks from low milliseconds to the nanosecond range.

300 ns defibrillation was observed and confirmed to require lower energy than monophasic shocks by almost an order of magnitude with no tissue damage. Additionally, the safety factor, the ratio of median effective doses for electroporative damage and defibrillation, was similar for both durations. To predict how defibrillation shocks of …

Understanding Radiation Resistance In Head And Neck Tumor Xenografts Using Diffuse Reflectance And Raman Spectroscopy, Sina Dadgar

Graduate Theses and Dissertations

Each year, 800,000 new patients are diagnosed with head and neck squamous cell carcinoma (HNSCC), a majority of whom are treated with a combination of daily fractions of radiation and weekly chemotherapy sessions for up to seven weeks. Current methods to evaluate treatment response of individual patients are limited to anatomical measurements of tumor burden using CT scan or MRI 4-8 weeks after completion of treatment. However, earlier knowledge of radiation-response prior to or at early days after commencement of therapy can aid oncologist with escalating and de-escalating treatment plans for exceptionally non-responding and responding patients. Such a knowledge can …

Low-Intensity Vibration Restores Nuclear Yap Levels And Acute Yap Nuclear Shuttling In Mesenchymal Stem Cells Subjected To Simulated Microgravity, Matthew Thompson, Kali Woods, Joshua Newberg, Julia Thom Oxford, Gunes Uzer

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Reducing the musculoskeletal deterioration that astronauts experience in microgravity requires countermeasures that can improve the effectiveness of otherwise rigorous and time-expensive exercise regimens in space. The ability of low-intensity vibrations (LIV) to activate force-responsive signaling pathways in cells suggests LIV as a potential countermeasure to improve cell responsiveness to subsequent mechanical challenge. Mechanoresponse of mesenchymal stem cells (MSC), which maintain bone-making osteoblasts, is in part controlled by the “mechanotransducer” protein YAP (Yes-associated protein), which is shuttled into the nucleus in response to cyto-mechanical forces. Here, using YAP nuclear shuttling as a measurement outcome, we tested the effect of 72 h …

Smart Motor Syringe System, Conard Chan, Jenny Chiao

Electrical Engineering

Syringe pumps are widely used in many research applications especially in the applications that need precise control. Today most medical research utilizes syringes to control the fluid being pumped to the experiment objects. In most cases microscopic or nano-scopic motion control is required to acquire optimal results, such application includes purification of DNA/RNA from contaminants[1]. The high precision required to control the syringe pump makes it difficult to perform manually. This paper focuses on the design of an intelligent syringe pump motor control system to achieve reliable and precise control for biomedical experiments. This project improves medical research quality with …

An Impedimetric Aptasensing System For The Rapid Detection Of Salmonella Typhimurium, America Sotero

Graduate Theses and Dissertations

Salmonella Typhimurium is a foodborne pathogen associated with raw and undercooked eggs, poultry, beef, fruits, and vegetables. In the United States, Salmonella is responsible for approximately 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths annually. For many years, conventional detection methods such as culture-dependent and PCR-based methods have been the “golden standards” for the detection of this pathogen due to their high sensitivity and reliability. However, they still have some disadvantages such as long enrichment steps and high costs that need to be overcome. The development of a rapid and reliable method for the detection of S. Typhimurium is needed …

The Use Of Nanoparticles And Electrospun Fibers For Intravaginal Delivery To Treat Viral And Bacterial Infections And Electrophysiological Measurements Of Synthetic Chloride Channels., Farnaz Minooei

Electronic Theses and Dissertations

Female reproductive viral and bacterial infections affect millions of women worldwide. Given the diversity and magnitude of these unmet reproductive health challenges, topical administration of antiretrovirals (ARVs) and antibiotics have emerged as promising approaches to maintain and restore reproductive health. However, currently available intravaginal dosage forms often suffer from low user adherence and the need for frequent, daily administration to achieve therapeutic effect. To address these challenges, the broad goal of this research was to focus on the development of new localized nanoparticle (NP) and electrospun fiber dosage forms to prolong the delivery and enhance the efficacy of active agents …

The Effects Of Solution Condition On Virus Filtration Performance, Fnu Namila

Graduate Theses and Dissertations

Virus filtration is an integral part of the downstream purification of mammalian cell culture-derived biotherapeutics to assure the viral safety of the products. Virus filtration membranes remove viruses based on a size-exclusion mechanism. Commercial parvovirus filers possess unique membrane structure and are designed to remove smaller non-enveloped parvoviruses with size 18-26 nm. However, some filters face issues, such as pre-mature fouling, the decline of filtrate flux, and reduction in virus retention. This doctoral dissertation focused on identifying the factors that influence the filtrate flux and the virus retention capability of commercial virus filters. The effects of solution pH and ionic …

Projecting Water Available For Irrigation Use And Identifying Water Supply Stress Under Climate Change Scenarios In Selected U.S. Fruit And Vegetable Production Regions, Andrew Shaw

Graduate Theses and Dissertations

Climate change affects water resources differently across geospatial regions in the United States (U.S). There is a concern of how water availability will be affected by changes in long-term temperature and precipitation patterns, specifically in major production regions for eight fruit and vegetable crops. The effects on surface water available for irrigation use and supply stress in five regions containing 31 Agricultural Statistics Districts (ASDs) were assessed. The Water Supply Stress Index Model was used and modified to project water available for irrigation use across nine climate scenarios driven by historical data, five General Circulation Models, two population scenarios, and …

Imparting 3d Representations To Artificial Intelligence For A Full Assessment Of Pressure Injuries., Sofia Zahia

Electronic Theses and Dissertations

During recent decades, researches have shown great interest to machine learning techniques in order to extract meaningful information from the large amount of data being collected each day. Especially in the medical field, images play a significant role in the detection of several health issues. Hence, medical image analysis remarkably participates in the diagnosis process and it is considered a suitable environment to interact with the technology of intelligent systems. Deep Learning (DL) has recently captured the interest of researchers as it has proven to be efficient in detecting underlying features in the data and outperformed the classical machine learning …

Development Of A Pediatric Cardiac Assist Maglev Pump For Use With A Universal Driver System., Landon Heath Tompkins

Electronic Theses and Dissertations

Heart failure (HF) remains the leading cause of death, affecting 26 million adults worldwide and 6.5 million adults in the United States. Pediatric HF patients have been a historically underserved population with few options for mechanical circulatory support (MCS) therapy, a leading treatment as an alternative to heart transplantation. To address this clinical need, the Inspired Universal MagLev System is being developed; a low cost, universal magnetically levitated extracorporeal MCS system with interchangeable single-use pumps that will ultimately provide adult and pediatric patients ventricular and respiratory assist therapies. The Inspired Pediatric VAD is the first single-use pump application for this …

Polyrad -- Protection Against Free Radical Damage, Hannah Kim, Yin Tse, Andrew Webb, Ethan Mudd, Muhammad Raisul Abedin, Melanie R. Mormile, Subhadeep Dutta, Kaushal Rege, Sutapa Barua

Biological Sciences Faculty Research & Creative Works

The effects of elevated levels of radiation contribute to the instability of pharmaceutical formulations in space compared to those on earth. Existing technologies are ineffective at maintaining the therapeutic efficacies of drugs in space. Thus, there is an urgent need to develop novel space-hardy formulations for preserving the stability and efficacy of drug formulations. This work aims to develop a novel approach for the protection of space pharmaceutical drug molecules from the radiation-induced damage to help extend or at least preserve their structural integrity and potency. To achieve this, free radical scavenging antioxidant, Trolox was conjugated on the surface of …

Spatially Directed Functionalization By Co-Electropolymerization Of Two 3,4-Ethylenedioxythiophene Derivatives On Microelectrodes Within An Array, Benjamin J. Jones, Carol Korzeniewski, Jefferson H. Franco, Shelley D. Minteer, Ingrid Fritsch

Chemistry & Biochemistry Faculty Publications and Presentations

Electrodeposited conductive copolymer films with predictable relative properties (quantities of functional groups for further modification and capacitance) are of interest in sensors, organic electronic materials and energy applications. Potentiodynamic copolymerization of films in aqueous solutions of two different thiophene derivatives, (2,3-dihydrothieno[3,4-b]dioxin-2-yl) methanol (1) and 4-((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)-methoxy)-4-oxobutanoic acid (2), containing 0.02 M total monomer (0, 25, 34, 50, 66, 75, 100 mol% 2), 0.05 M sodium dodecyl sulfate, and 0.1 M LiClO4, on gold microelectrodes in an array was investigated. Decreasing monomer deposited (m) from 0 to 100 mol% 2 is attributed to a decreasing pH that inhibits electropolymerization. Molar ratios of …

Cellular Attachment On Poly(Lactic Acid) For Use In Tissue Engineering, Stephen R. Hunter

Masters Theses

Tissue engineering is a promising new method for organ regeneration. This method can be used to repair damaged tissue, or possibly replace a fully functional organ. In summary, a biopsy is taken from a donor, isolated, then grown onto a framework resembling an organ. Once grown; it is then transplanted into the patient. Over time, the body will degrade the scaffold, leaving the organ or tissue in its place. As this scaffold is present in the body for an extended time; factors like biocompatibility, toxicity, immunogenicity, and structural stability must be researched.

Several polymers have already been researched for use …

A Comparison Of Methods To Measure Crop Water Use In South Carolina, Andrew C. Ewing

All Theses

The objective of this thesis was to compare cost-effective methods of measuring crop water use, known as evapotranspiration (ET), in South Carolina’s humid climate. The methods analyzed were the surface renewal method (SR), the Eddy Covariance method (EC), large in-field weighing lysimeters, a newly developed pressure differential device (PDD), a Class A Evaporation pan, and the Penman-Monteith equation. In the first chapter, ET measurements obtained by SR were compared to ET measured by EC and weighing lysimeters. For reference, EC and SR track the energy budget to estimate ET, while the weighing lysimeters used in this study are box-like containers …

An Investigation Into The Development Of A Low Cost, Easy To Use Seizure Analysis Tool., Cody Dean

Masters Theses

The need for collaborating and sharing data and research between doctors, researchers, universities and patients has never been more necessary. We are seeing firsthand how a deadly virus can completely devastate the world in a matter of months and being able to react quickly is the top priority. Open source tools are making it possible to share research and learnings about viruses like COVID-19 across countries, industries, and universities and these tools and philosophies extend across all areas of medical research.

The amount of data that is being collected within the medical industry is increasing at an exponential rate and …

3d Printed Microporous Collagen Constructs Using The Freeze-Fresh Methodology, Thais Sousa Senzano

Theses and Dissertations

Scaffold microporosity is known to play a critical role in governing cellular response including cell migration, proliferation, and tissue-specific differentiation. While fabrication approaches such as solvent leaching and freeze-casting are commonly used for the generation of microporous biomaterial scaffolds, these methods provide little control over scaffold geometry and creation of complex tissue structures. Extrusion-based 3D printing, an additive manufacturing method, is a highly versatile layer-by-layer printing approach that allows for the fabrication of easily customizable 3D scaffolds with complex architecture using a vast selection of polymeric bioinks. These 3D printed constructs are porous at the macroscale, but achieving microporosity (i.e., < 100 μm) in printed constructs is challenging due to the sub-optimal resolution of the extrusion-based printing method. A recent study using alginate inks introduced a new fabrication technique termed Freeze-FRESH(FF)that combines extrusion printing and freeze-casting approaches to generate 3D constructs with hierarchical microporosity. However, the porosity of the resultant alginate constructs was comparable despite changing the freezing temperature. In the current study, the FF method was modified to print collagen constructs with greater control of microporous architecture. Highly concentrated collagen type I ink was used to 3D print collagen constructs using the freeform reversible embedding of suspended hydrogels (FRESH)approach. Modification of the FF technique entailed melting of the FRESH bath post printing via incubation at 37 °C followed by freezing and lyophilization to allow for collagen gelation and better heat transport during the freezing process. The effect of freezing temperature on micropore size, swelling degree, degradation, and mechanical properties of printed constructs was assessed. Finite element (FE) models were generated to predict the mechanical properties of microporous scaffolds. In addition, the effect of microporosity on Saos-2 cell morphology, proliferation, infiltration, and ALP activity was evaluated. Results from the study showed that freezing temperature effectively modulated micropore size and that constructs with larger micropore size were more stable. Microporosity had no effect on swelling ratio yet caused a decrease in mechanical properties of collagen constructs; FE models confirmed experimental results. Cell metabolic activity and infiltration was enhanced in microporous constructs with larger pore size, yet there was no effect on cell morphology, and ALP activity. In conclusion, the modified FF technique can be effectively used to fabricate hierarchically porous 3D collagen constructs.

Multiphoton Microscopy And Deep Learning Neural Networks For The Automated Quantification Of In Vivo, Label-Free Optical Biomarkers Of Skin Wound Healing, Jake D. Jones

Graduate Theses and Dissertations

Non-healing ulcerative wounds that occur frequently in diseases such as diabetes are challenging to diagnose and treat due to numerous possible etiologies and the variable efficacy of wound care products. With advanced age, skin wound healing is often delayed, leaving elderly patients at high risk for developing these chronic injuries. As it is challenging to discriminate age-related delays from disease-related chronicity, there is a critical need to develop new quantitative biomarkers that are sensitive to wound status. Multiphoton microscopy (MPM) techniques are well-suited for 3D imaging of epithelia and are capable of non-invasively detecting metabolic cofactors (NADH and FAD) without …

Network-Level Mechanisms Underlying Effects Of Transcranial Direct Current Stimulation (Tdcs) On Visuomotor Learning, Pejman Sehatpour, Clément Dondé, Matthew J. Hoptman, Johanna Kreither, Devin Adair, Elisa Dias, Blair Vail, Stephanie Rohrig, Gail Silipo, Javier Lopez-Calderon, Antigona Martinez, Daniel C. Javitt

Publications and Research

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation approach in which low level currents are administered over the scalp to influence underlying brain function. Prevailing theories of tDCS focus on modulation of excitation-inhibition balance at the local stimulation location. However, network level effects are reported as well, and appear to depend upon differential underlying mechanisms. Here, we evaluated potential network-level effects of tDCS during the Serial Reaction Time Task (SRTT) using convergent EEG- and fMRI-based connectivity approaches. Motor learning manifested as a significant (p <.0001) shift from slow to fast responses and corresponded to a significant increase in beta-coherence (p <.0001) and fMRI connectivity (p <.01) particularly within the visual-motor pathway. Differential patterns of tDCS effect were observed within different parametric task versions, consistent with network models. Overall, these findings demonstrate objective physiological effects of tDCS at the network level that result in effective behavioral modulation when tDCS parameters are matched to network-level requirements of the underlying task.

Improving Long-Term Vascular Graft Viability Using Peritoneal Pre-Implantation And Epsin-Mimetic Peptides, Mahyar Sameti

Theses and Dissertations

The primary goal of this project was to produce and develop a tissue-engineered small-diameter vascular graft which can replace the arteries and function well for long-term grafting. Implanting an electrospun tubular conduit into the peritoneal cavity to recruit autologous cells prior to grafting the conduit into the artery is a method to achieve this goal. Incorporating an epsin-mimetic peptide on the conduit prior to grafting is another proposed method to reach the goal. This will be accomplished through four complementary studies: (1) determining the effect of a pouch in peritoneal pre-implantation and reducing the potential peritoneal adhesion formation;(2) determining the …

A Novel Method To Commercialize Medical Devices Initially Developed At California Polytechnic State University San Luis Obispo, Christina Grigorian

Master's Theses

California Polytechnic State University, San Luis Obispo is a university that encourages students to approach learning hands-on. As such, there is cutting-edge technology being developed by students in all departments on campus. Being that the university possesses an outstanding biomedical engineering department, there are groundbreaking medical devices that students are creating at Cal Poly SLO. These are devices that can better the lives of individuals suffering from ailments or fulfill needs in the medical industry. Subsequently, it is vital that these devices make it out of campus laboratories and into the hands of consumers. In order to move a product …