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Florida Institute of Technology

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Articles 31 - 60 of 108

Full-Text Articles in Biomedical Engineering and Bioengineering

Optimizing Left Ventricular Assist Device Hemodynamics Via Patient Specific Computational Analysis, Jasmine Josefina Martinez Jul 2022

Optimizing Left Ventricular Assist Device Hemodynamics Via Patient Specific Computational Analysis, Jasmine Josefina Martinez

Theses and Dissertations

The best treatment for patients with end stage heart failure is a heart transplant but given the scarcity of donor hearts, a promising alternative treatment has become left ventricular assist devices (LVAD). However, complications such as right heart failure, stroke, and adverse hemodynamic outcomes continue to occur. This thesis will cover investigations into continuous flow LVAD treatment optimization techniques to improve patient outcomes. Optimization techniques explored include an in-house developed optimization algorithm that is completed in three phases on a computational lumped parameter model that is representative of the cardiovascular system using an electrical circuit analogy. This three-phase optimization technique …

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Computer Vision And Machine Learning Applications In Cellular Images And Clinical Data, Guochang Ye May 2022

Computer Vision And Machine Learning Applications In Cellular Images And Clinical Data, Guochang Ye

Theses and Dissertations

With the progressive development of artificial intelligence (AI), automated analysis has been explored for substituting tedious manual methods in cellular image analysis. Additionally, medical information not included in the conventional statistical methods is now being reconsidered with AI-based personalized medicine. The adaptivity and flexibility of AI ensure its efficiency and accuracy. In this work, computer vision and machine learning (ML) methods under the scope of AI are explicitly investigated and applied to cellular images and clinical data for cytological analysis and to provide diagnosis-based assistance/predictions. Firstly, novel computer vision algorithms achieve cell detection and differentiation estimation on phase-contact microscopic images …

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Effects Of Orthopedic Implant And Host Bone Properties On Stress-Shielding Induced Osteopenia, Scott Jason Jan Baskerville May 2022

Effects Of Orthopedic Implant And Host Bone Properties On Stress-Shielding Induced Osteopenia, Scott Jason Jan Baskerville

Theses and Dissertations

Stress shielding is a term commonly used in literature to describe a bone density reducing phenomenon which occurs due to long-term exposure of bone tissue to sub-homeostatic levels of mechanical stimuli. A number of mechanobiological models ranging in complexity and purpose have been developed with the general overall intent of predicting bone remodeling behavior under a set of prescribed conditions. A previously developed heuristic model is expanded in the present work through model calibration with physiological data and the development of a reduced bone-implant-construct (BIC) mechanical model configurable for patient factors such as age, gender, and associated bone properties. The …

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Cellular Migration As A Function Of Magnetic Field Intervention, Amy Marie Vecheck May 2022

Cellular Migration As A Function Of Magnetic Field Intervention, Amy Marie Vecheck

Theses and Dissertations

This work aims to assess cellular migration in three-dimensional structures as a function of Zeeman resonance. By using Zeeman resonance to initialize intersystem crossing of electrons, also known as the Radical Pair Mechanism, bioenergetics processes would be modulated. Processes such as oxygen consumption rate and extracellular acidification rate are indicative of cellular respiration and glycolysis and can be altered based on the orientation of the magnetic field applied: parallel and perpendicular, respectively. This study focused on the parallel orientation and looked to used Zeeman resonance to increase flavin adenosine dinucleotide, which results in preventing the breakdown of F-actin. Cellular viability …

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Influence Of Mouthguard Design On Sports Performance And Injury Prevention, Mohammad Ahmed May 2022

Influence Of Mouthguard Design On Sports Performance And Injury Prevention, Mohammad Ahmed

Theses and Dissertations

Contact sports are associated with some invisible injuries after the incident when symptoms do not appear until weeks after. This can be dangerous as players may continue to engage in the sport and risk further injury. Athletic mouthguards are used to reduce the risk of injury, but there is insufficient data to quantify the effectiveness of mouthguard design on sports performance and injury prevention. In this work, the thickness and material selection of the mouthguard design were characterized in terms of airway resistance, electromyography muscle activation, and energy absorption. First, the effect of thickness on the condyle and temporal bone …

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Stress Analysis Based On Ecg And Eeg, Eyad Talal Attar Jul 2021

Stress Analysis Based On Ecg And Eeg, Eyad Talal Attar

Theses and Dissertations

Stress is a significant risk factor for various diseases such as hypertension, heart attack, stroke, and even sudden death. In many studies, stress is linked to decision making, performance, and learning. The heart rate variability (HRV) can be measured from the Electrocardiogram (ECG) and is defined as the variation of the interval between two consecutive heartbeats (heart rate). Heart rate variability is also an indicator of the balance between the sympathetic and parasympathetic branches of the autonomic nervous system. HRV refers to variations of heart rate in a certain amount of time. Heart rate variability (HRV) is a relatively new …

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Endothelial Response In 2d And 3d To Doses Of Photosensitive Carbon Monoxide Releasing Molecules With Improved Activation, Nicholas Duc Huynh Jul 2021

Endothelial Response In 2d And 3d To Doses Of Photosensitive Carbon Monoxide Releasing Molecules With Improved Activation, Nicholas Duc Huynh

Theses and Dissertations

Cardiovascular disease (CVD) is the leading cause of death worldwide in large part due to atherosclerotic obstruction of blood vessels. Limitations with current treatment approaches include restenosis in stenting and viable donor-tissue for bypass grafts, and this has motivated research combining the fields of drug delivery and tissue engineering for alternative approaches. The use of carbon monoxide as a potential therapeutic agent in the treatment of CVD has shown potential impacts on vasodilation and anti-inflammation. The goal of this study was to develop a system to elucidate the response of endothelial cells post-exposure to different concentrations of carbon monoxide releasing …

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Bioink Optimization And Effects Of Microgravity On 3d Bioprinted Cell Laden Constructs, Likitha Somasekhar May 2021

Bioink Optimization And Effects Of Microgravity On 3d Bioprinted Cell Laden Constructs, Likitha Somasekhar

Theses and Dissertations

Bioengineered 3D tissue constructs have gained attention as in vitro tools for the study of cell-cell and cell-matrix interactions and are being explored for potential use as experimental models for mimicking human tissues. One of the main problems in tissue engineering is the necessity to vascularize complex engineered tissues and sacrificial printing has been recognized as a possible solution to vascularization of the bioprinted tissues. Research studies have demonstrated that exposure to microgravity in space induces adaptive alterations in vascular structure and function. Changes in the morphology and gene expression is observed when endothelial cells are exposed to microgravity and …

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A Comparative Study To Assess The Osteogenic Potential Of Competing Bioceramics For Bone Tissue Engineering, Nashaita Patrawalla May 2021

A Comparative Study To Assess The Osteogenic Potential Of Competing Bioceramics For Bone Tissue Engineering, Nashaita Patrawalla

Theses and Dissertations

Biomimetic composite scaffolds comprising of bioactive ceramic-based materials incorporated within a polymeric framework have shown considerable promise for use in bone tissue engineering (BTE) applications. Although bioceramics have shown immense promise for use in BTE, few studies have performed a head-to-head comparison of the osteogenic properties of the most promising bioceramic materials. The goal of this study was to compare three different bioceramics – Bioglass 45S5 (BG), Laponite XLG (LAP), and β-Tricalcium Phosphate (TCP) – on the physical properties (i.e., swelling, stability, compressive modulus, bone bioactivity) of methacrylated collagen (CMA) hydrogels and osteogenic differentiation of human MSCs (hMSCs) encapsulated within …

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Validation Of Arterial Distensibility Neural Network Model With Clinical Data, Cassondra Michelle Petersen May 2021

Validation Of Arterial Distensibility Neural Network Model With Clinical Data, Cassondra Michelle Petersen

Theses and Dissertations

Cardiovascular diseases continue to plague the world as the number one killer of adults each year. As cardiovascular diseases can start with seemingly no symptoms, heart disease has been coined as the silent killer. With the ongoing COVID-19 global pandemic, the need for advances in cardiovascular advances has become even more prevalent as this virus is known to cause more severe damage to those who have underlying cardiovascular problems. These two reasons show the dire clinical need for researchers to continue to use novel techniques such as neural networks to find new approaches for helping physicians non-invasively and quickly add …

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Cardiovascular Intelligence: Novel Quantitative Cardiology, Deep Learning And Machine Learning Models To Predict Clinical Outcomes, Vignesh Balasubramanian May 2021

Cardiovascular Intelligence: Novel Quantitative Cardiology, Deep Learning And Machine Learning Models To Predict Clinical Outcomes, Vignesh Balasubramanian

Theses and Dissertations

Arterial compliance has been recognized as a critical parameter in governing pulsatile flow dynamics. It has traditionally been assumed constant throughout the cardiac cycle. Its computation has been based either on the classic Windkessel model in diastole or the stroke volume over pulse pressure method in systole. We proposed a novel compliance-pressure loop (CPP loop) approach to quantify arterial compliance and compare it to existing linear and nonlinear methods. This was followed by an analysis of increased pulse wave reflections in hypertension due to impedance mismatching and how the effective energy transmission to the vasculature is compromised. Their quantification in …

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Improving Long-Term Vascular Graft Viability Using Peritoneal Pre-Implantation And Epsin-Mimetic Peptides, Mahyar Sameti Dec 2020

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 …

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3d Printed Microporous Collagen Constructs Using The Freeze-Fresh Methodology, Thais Sousa Senzano Dec 2020

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.

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Development Of A Graphical User Interface For Ecg Signals Classification Using Statistical Features Analysis, Mousa Hammad S Aldosari Aug 2020

Development Of A Graphical User Interface For Ecg Signals Classification Using Statistical Features Analysis, Mousa Hammad S Aldosari

Theses and Dissertations

Cardiac diseases are the most common cause of mortality in the world. The detection of cardiac arrhythmias is not a straightforward process, since minor variations in the electrocardiogram (ECG) signals cannot be easily identified manually. Therefore, automatic detection and classification of cardiac arrhythmia would shorten the diagnostic time and accelerate medical intervention resulting in reducing the mortality rate. In this thesis, I have developed a simple and low-cost computer-aided diagnostic system using MATLAB-based Graphical User Interface (GUI) to facilitate fast operation and access to the data along with the overall accuracy of the system. The acquired ECG signals are processed …

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Mechanical And Material Properties Of Nitinol And Its Application To Stents, Ariana Solis Eichler Aug 2020

Mechanical And Material Properties Of Nitinol And Its Application To Stents, Ariana Solis Eichler

Theses and Dissertations

Nitinol is a functional material with superelastic and shape memory properties derived from its unique molecular structure. The purpose of this thesis is to explore how the material and mechanical properties of self-expanding Nitinol stents affects the forces applied to arterial walls during stent deployment compared to the traditional balloon-expanding stainless steel stents, in addition to contrasting thin and thick-walled pressure vessel mathematical models. Nitinol’s mechanical properties can be optimized for stent applications by tailoring its processing procedures. Nitinol stents demonstrated a reduced circumferential hoop stress on the vessel wall and greater factor of safety with respect to vessel rupture …

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An Experimental And Computational Mechanical Analysis Of Bone Anchors And Substrate Interface, Samantha May Schultz Aug 2020

An Experimental And Computational Mechanical Analysis Of Bone Anchors And Substrate Interface, Samantha May Schultz

Theses and Dissertations

Screw loosening is a common concern in orthopedic surgery. Therefore, this study is a computational and experimental evaluation of bone substrate and cortical screw interface. An axial load test was performed in an Instron with titanium alloy screws with 2.7 mm, 3.5 mm, and 4.5mm diameter orthopedic cortical screws inserted into SawBone with densities varying from 10 to 50 pounds per cubic foot (PCF), incrementing in sets of 10 PCF. SawBone was chosen in place of human bone because it has been shown to emulate the same mechanical properties (1). Twelve samples were prepared for each screw size and substrate …

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Development Of A Novel System For The Analysis Of The Cardiovascular And Autonomic Nervous Systems, Seyedmohsen Dehghanojamahalleh Dec 2019

Development Of A Novel System For The Analysis Of The Cardiovascular And Autonomic Nervous Systems, Seyedmohsen Dehghanojamahalleh

Theses and Dissertations

Chapter 1 - An introduction to autonomic nervous system (ANS) and cardiovascular system (CVS): The performance of the ANS can be evaluated by quantizing the changes made by the autonomic nervous system. The most common parameters that are being used in autonomic nervous system assessment tests are blood pressure, heart rate, pressure pulse wave velocity, heart rate variability, and pulse waveform. In this dissertation, we designed and developed a system that assesses the activity of these two systems. Therefore, we represented four methods to 1- evaluate the dependence of neuro- and cardiovascular systems on sex, 2- non-invasively estimate the blood …

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Gene Expression Studies For Analyzing Effects Of Space Radiation In Tissues, Amatulshakoor Mohammed Farooqui Jul 2019

Gene Expression Studies For Analyzing Effects Of Space Radiation In Tissues, Amatulshakoor Mohammed Farooqui

Theses and Dissertations

Human exploration beyond the earth's orbit poses many risks for the crew on these missions. One of the major health risks is exposure to space radiation environment beyond the earth’s magnetic field. The space environment exposes astronauts to high levels of ionizing radiation such as galactic cosmic rays. The radiations can have acute and delayed effects on the human body. The primary response to tissue injury is increased oxidative stress and inflammation. The overall objective of this study was to analyze the effects of ionizing radiation in heart tissue by quantifying its impact on the expression of genes that correlate …

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Controlling Co Dose From Corm-Loaded Electrospun Scaffolds With Diffusion-Based Modeling And Experimental Assessment Of Endothelial Cell Response, Kenyatta S. Washington Jul 2019

Controlling Co Dose From Corm-Loaded Electrospun Scaffolds With Diffusion-Based Modeling And Experimental Assessment Of Endothelial Cell Response, Kenyatta S. Washington

Theses and Dissertations

Cardiovascular disease (CVD) accounts for one in every five deaths in the United States alone due to occlusion in small diameter (< 6 mm) vessels. The current treatment options includes bypass grafting; however, more than 30 percent of patients do not have viable saphenous veins for autologous grafting [1]. Therefore, tissue engineering is being considered as an alternative approach. The overall goals of this project were to develop a tissue engineered vascular graft with the incorporation of carbon monoxide releasing molecules (CORMs) and to determine the impacts of carbon monoxide (CO) on endothelial cells (ECs) with the goal of promoting a functional endothelium within the graft. This was accomplished through two complementary studies: investigating the impacts of CO-loaded electrospun scaffolds on ECs for cardiovascular applications and diffusion-based modeling of drug delivery of gasotransmitters from tissue engineered scaffolds. In the first study, we extended the maximum in vitro incubation time to permit better cellular attachment and proliferation with a newly-synthesized, more hydrophobic CORM (DK3) and established the impact of CORMs on EC viability and function (e.g. reactive oxygen species (ROS) products, and ROS levels). We further investigated toxicity and biocompatibility of a newly synthesized CORM (DK4) loaded within PCL thin films and nanoparticles. We concluded that the DK4 and other compounds are not toxic at doses ranging from 0 – 50 μg/mL to the ECs both within nanoparticles that can be internalized within cells. We also conducted an in vivo pilot study to determine graft biocompatibility and preliminary results showed that CORM implants maintain mechanical integrity, support blood flow, and do not show toxicity for up to six weeks. In the second study, we validated a computational model and analyzed the output of CO delivery to better understand and control local dose. For CO release, this model is necessary because of the limitations with real-time experimental analysis and the need to better understand the dose available to the cells. We demonstrated that the validated model can be used to predict drug availability to cells for a variety of scaffolds and drug molecules. Our simulated results suggest that only a fraction of the initial concentration of gasotransmitters released from fibers that enters the interstitial fluid in vivo, or culture media in vitro, will be available to cells. We also demonstrated that fiber orientation and fiber diameter are important for drug delivery, but fiber density provides even more important information. The more contact area within the fiber scaffolds is equivalent to experimental conditions with more cell attachment and spreading. These parameters are not only important for traditional tissue engineering, but also for drug delivery. Overall, these results demonstrate the feasibility of making a tissue engineered vascular graft with the incorporation of CORMs and validating he importance of computational modeling of diffusion-based transport of CO. Future work will involve performing surface modifications to enhance cell attachment and proliferation, using the developed computational model to better predict dose available to cells, and experimentally determining impact of CO dose on ECs.

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Bioprinting Of 3d Perfusable Structures Using An Extrusion-Based System, Prabhuti Kharel Jun 2019

Bioprinting Of 3d Perfusable Structures Using An Extrusion-Based System, Prabhuti Kharel

Theses and Dissertations

Bioprinting is a technique of creating 3D cell laden structures by accurately dispensing biomaterial to form complex synthetic tissue. Bioprinting is a process of additive manufacturing where the cell functionality and viability is preserved within the printed structure. Bioprinting is a promising alternative to produce physiologically relevant 3D structures that mimic the native tissue. However, fabrication of complex structures with vascularization has been a major challenge in bioprinting. To overcome this challenge sacrificial printing in combination with fugitive inks has been explored to create vascularize structures. The objective of this study is to fabricate hollow channels within the bioprinted structure …

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Hrv - Ecg Generator: Software For Testing Heart Rate Variability Detection, Matthew Joseph Pogorelec May 2019

Hrv - Ecg Generator: Software For Testing Heart Rate Variability Detection, Matthew Joseph Pogorelec

Theses and Dissertations

Heart rate variability (HRV) has been shown to serve as an effective diagnostic and prognostic tool in a variety of clinical applications, including for patients who have suffered from myocardial infarction, sepsis and liver cirrhosis. There currently exist a variety of devices and software to quantify HRV based on RR interval series collected from ECG data. However, as the uses for HRV expand, a greater variety of devices for different applications are being designed and developed. Thus, it is useful to have available a method for efficiently testing preliminary software. The HRV/ECG Generator software is designed to build both an …

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Finite Element Analysis Of Humerus With Impact At Distal End And The Mechanical Effect Of Bone Rehydration, Amy Gutierrez Dec 2018

Finite Element Analysis Of Humerus With Impact At Distal End And The Mechanical Effect Of Bone Rehydration, Amy Gutierrez

Theses and Dissertations

Numerical modeling accuracy is dependent upon correct material property determination and input. This thesis demonstrates the importance in both numerical modeling and material characterization, two aspects of biomedical research that are intimately linked. The first study investigates the shear forces experienced on the humerus from a humeral impact on the distal end using 3D CAD model of a humerus and ANSYS for a finite element analysis. The humeral bone was analyzed with an impact on the distal end to signify falling on the elbow. A humeral model and a humeral model with a plate were both statically and dynamically simulated …

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Analysis And Classification Of 3-D Printed Collagen-Bioglass Matrices For Cellular Growth Utilizing Artificial Neural Networks, Trevor Schmitt Dec 2018

Analysis And Classification Of 3-D Printed Collagen-Bioglass Matrices For Cellular Growth Utilizing Artificial Neural Networks, Trevor Schmitt

Theses and Dissertations

Introduction: Recent advances have shown the influence of biomimetic design on modulation of the extracellular matrix (ECM) and the role stiffness of it plays in cellular behavior. 2-D models for cellular growth poorly recapitulate the natural environment of cells, whereas application of a 3-D ECM model allows for a more biomimetic design for modeling cellular behavior. Integration of 45S5 Bioglass provides and osteostimulatory mineral component to these 3-D models, allowing for better mimicry of orthopedic design, affecting the mechanical and physiochemical properties of the ECM and leading to an increase in osteogenic behavior. 3-D Bioprinting allows for custom fabrication of …

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A Hard-Real-Time Juggling Simulator To Shape Human Sensitivity To Cues And Coordination Of Muscles, Robert W. Nickl Sep 2018

A Hard-Real-Time Juggling Simulator To Shape Human Sensitivity To Cues And Coordination Of Muscles, Robert W. Nickl

Link Foundation Modeling, Simulation and Training Fellowship Reports

Many virtual reality tasks incorporate auditory and haptic (or touch) feedback, in addition to visual displays of spatial information. Non-visual feedback modalities such as the former increase realism; but they may have an ancillary benefit of increasing human motor performance and learning. One task for which this has been exhibited is paddle juggling, or vertically bouncing a ball off of a rigid elastic planar surface. For the objective of hitting the ball toward a target height, visual feedback is sufficient. Yet, previous studies have shown that non-visual feedback----specifically haptic---both is sufficient in the absence of vision to maintain stable ball …

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An Analysis Of The Relationship Between Orthopedic Drill Bit And Screw Diameter On Drilling Energy And Axial Load Pullout Strength, Scott J. J. Baskerville Jul 2018

An Analysis Of The Relationship Between Orthopedic Drill Bit And Screw Diameter On Drilling Energy And Axial Load Pullout Strength, Scott J. J. Baskerville

Theses and Dissertations

The number of orthopedic procedures performed per year in the United States is expected to grow to 6.6 million by 2020 (1). Most of these surgeries involve some degree of bone drilling and screw fixation, putting many patients at risk of the adverse effects of the heat-induced osteonecrosis which can limit the holding strength of bone screws and the efficacy of the screw-dependent fixtures. Excessive heat-induced osteonecrosis can occur when surgeons prolong the drilling procedure to avoid drill plunge, which can cause damage to soft neurovascular tissues local to the drilling site (2). The SMARTdrill system used in this study …

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Using Dispersive Raman Spectroscopy To Assess Remodeling In Vascular Constructs Used In Tissue Engineering, Andrea S. Theus May 2018

Using Dispersive Raman Spectroscopy To Assess Remodeling In Vascular Constructs Used In Tissue Engineering, Andrea S. Theus

Theses and Dissertations

Tissue engineered vascular grafts (TEVGs) are a promising alternative to surgery for the treatment of thrombotic occlusion of small diameter (< 6 mm) arteries. It is important that TEVG composition prevent compliance mismatch. Both initial protein incorporation and cellular remodeling are important for blended TEVG compliance. Understanding the distribution of extracellular matrix (ECM) components is also important and may dictate the remodeling response. Raman spectroscopy has been used to assess components of engineered scaffolds non-destructively. However, Raman has not been applied to semi-quantitatively assess 3D engineered-tissues and cellular remodeling of blended materials with low-scattering natural and high-scattering synthetic components. This is important due to the increased use of synthetic biomaterials for TEVG applications. The overall goal of this study was to develop a technique to assess the cellular and matrix remodeling response. Electrospun meshes were prepared with 100% poly(ε-caprolactone) (PCL), 90% PCL/collagen, and 90% PCL/fibrinogen. XPS and Raman results showed differences of protein distribution when incorporated into a PCL scaffold and differences in the resulting effects with cell culturing and incubation. Raman spectra was acquired for all pure materials individually (e.g. PCL, collagen, and fibrinogen) to determine the unique spectral fingerprint of each material. Protein peaks of interest were identified (e.g. 740 and 1040 cm-¹ ) and were analyzed when protein was incorporated into the electrospun meshes. Raman spectra was acquired for the pure PCL control and blended scaffold conditions. The protein peaks remained relevant for proteins even when incorporated into the high scattering PCL polymer and showed remodeling due to incubation and cell culturing over 21 days. Spectra were also analyzed with multi-factor processing techniques (e.g. MFA) and showed that separation between appropriate sample groups can be achieved even with large amounts of spectral data sets. Biochemical analysis (e.g. Hyp, µ-BCA assay) was done to determine if specific remodeling responses, degradation and/or release occur with incubation and culturing of smooth muscle cells. These results showed a negligible loss of protein within electrospun meshes with incubation and culture. Overall, we have shown that Raman spectroscopy can be used to semi-quantitatively detect the incorporation of low levels of specific proteins (e.g. collagen and fibrinogen) within electrospun meshes as well as changes that occur with mesh remodeling.

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Blue-Light Induced Biosynthesis Of Ros Contributes To The Signaling Mechanism Of Arabidopsis Cryptochrome, Mohamed A. El-Esawi, Louis David Arthaut, Nathalie Jourdan, Alain D'Harlingue, Justin J. Link, Margaret Ahmad, Carlos F. Martino Dec 2017

Blue-Light Induced Biosynthesis Of Ros Contributes To The Signaling Mechanism Of Arabidopsis Cryptochrome, Mohamed A. El-Esawi, Louis David Arthaut, Nathalie Jourdan, Alain D'Harlingue, Justin J. Link, Margaret Ahmad, Carlos F. Martino

Biomedical Engineering and Sciences Faculty Publications

Cryptochromes are evolutionarily conserved blue light receptors with many roles throughout plant growth and development. They undergo conformational changes in response to light enabling interaction with multiple downstream signaling partners. Recently, it has been shown that cryptochromes also synthesize reactive oxygen species (ROS) in response to light, suggesting the possibility of an alternate signaling mechanism. Here we show by fluorescence imaging and microscopy that H202 and ROS accumulate in the plant nucleus after cryptochrome activation. They induce ROS-regulated transcripts including for genes implicated in pathogen defense, biotic and abiotic stress. Mutant cryptochrome alleles that are non-functional in photomorphogenesis retain the …

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Targeting The Bacterial Orisome In The Search For New Antibiotics, Julia E. Grimwade, Alan C. Leonard Nov 2017

Targeting The Bacterial Orisome In The Search For New Antibiotics, Julia E. Grimwade, Alan C. Leonard

Biomedical Engineering and Sciences Faculty Publications

There is an urgent need for new antibiotics to combat drug resistant bacteria. Existing antibiotics act on only a small number of proteins and pathways in bacterial cells, and it seems logical that expansion of the target set could lead to development of novel antimicrobial agents. One essential process, not yet exploited for antibiotic discovery, is the initiation stage of chromosome replication, mediated by the bacterial orisome. In all bacteria, orisomes assemble when the initiator protein, DnaA, as well as accessory proteins, bind to a DNA scaffold called the origin of replication (oriC). Orisomes perform the essential tasks of unwinding …

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Impact Of Electrospun Conduit Composition And Peritoneal Pre-Conditioning On Patency And Remodeling Of Tissue Engineered Vascular Grafts, Mozhgan Shojaee Oct 2017

Impact Of Electrospun Conduit Composition And Peritoneal Pre-Conditioning On Patency And Remodeling Of Tissue Engineered Vascular Grafts, Mozhgan Shojaee

Theses and Dissertations

Overall goal of this project was to develop a tissue engineered vascular graft by implanting an electrospun tubular conduit into the peritoneal cavity to recruit autologous cells to it and provide the cells with the components of the hysiological environment prior to grafting the conduit into the artery. This was accomplished through three complimentary studies: finding the best ratio of poly(ε-caprolactone) (PCL) and collagen that improves inflammatory response within the peritoneal cavity; determining the effect of peritoneal pre-implantation and the amount of incorporated collagen on graft functionality; and reducing the potential side effect of peritoneal adhesion formation. In the first …

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Delivery Of Antioxidant And Anti-Inflammatory Agents For Tissue Engineered Vascular Grafts, Kenyatta S. Washington, Chris A. Bashur Sep 2017

Delivery Of Antioxidant And Anti-Inflammatory Agents For Tissue Engineered Vascular Grafts, Kenyatta S. Washington, Chris A. Bashur

Biomedical Engineering and Sciences Faculty Publications

The treatment of patients with severe coronary and peripheral artery disease represents a significant clinical need, especially for those patients that require a bypass graft and do not have viable veins for autologous grafting. Tissue engineering is being investigated to generate an alternative graft. While tissue engineering requires surgical intervention, the release of pharmacological agents is also an important part of many tissue engineering strategies. Delivery of these agents offers the potential to overcome the major concerns for graft patency and viability. These concerns are related to an extended inflammatory response and its impact on vascular cells such as endothelial …

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