Engineering Commons^™

Cerebro-Vascular Disruption Mediated Initiation And Propagation Of Traumatic Brain Injury In A Fluid Percussion Injury Model, Xiaotang Ma

Dissertations

Traumatic brain injury (TBI) is a major health problem for over 3.17 million people in the US. There is no FDA-approved drug for the treatment because the injury mechanisms have not been clearly identified. The knowledge gap is addressed here by the lateral fluid percussion injury (FPI) rat model, through the understanding of layer-structured mechanisms from physical vascular rupture to acute necrosis, as well as biochemical changes in perivascular space as secondary events.

Firstly, the cerebrovascular hemorrhage and related infarct volume are investigated as the primary events in moderate FPI, which is found to be increased with injury severity in …

The Co-Delivery Of Syngeneic Adipose-Derived Stromal Cells And Macrophages On Decellularized Adipose Tissue Bioscaffolds For In Vivo Soft Tissue Regeneration, Hisham A. Kamoun

Electronic Thesis and Dissertation Repository

Decellularized adipose tissue (DAT) bioscaffolds are a promising platform for the delivery of pro-regenerative cell populations with the goal of promoting adipose tissue regeneration. The current study investigated the effects of seeding DAT bioscaffolds with syngeneic bone marrow-derived macrophages and/or adipose-derived stromal cells (ASCs) on in vivo soft tissue regeneration. Methods were established to derive the macrophages from MacGreen mice, which were dynamically seeded onto the DAT scaffolds alone or in combination with ASCs. Seeded and unseeded scaffolds were implanted subcutaneously into C57Bl/6 mice. At 2 and 4 weeks, cell infiltration, angiogenesis, and adipogenesis were analyzed through histology and immunohistochemistry. …

Production And Purification Of Basic Fibroblast Growth Factor Fused To Two Collagen Binding Domains Expressed In E. Coli Bl21 Using Flask And Fed-Batch, Hazim Aljewari

Graduate Theses and Dissertations

Delivering effective and non-toxic doses of bioactive materials that can aid in activating tissue regeneration to wounded tissue has proven to be an enormous challenge. This study was designed to produce a potential therapeutic recombinant protein by fusing two collagen binding domains to basic fibroblast growth factors (bFGF) through a collagenase cleavage site linker, so it can release the bFGF in a wound site by the action of this enzyme. The novel fusion protein was expressed in Escherichia coli BL-21 (E. coli) using traditional flask shaker and fed-batch cultivation. Cell lysate was purified by FPLC using Immobilized metal affinity chromatography …

In Vivo Metabolic And Vascular Response To Hypoxia In Twist Knockdown Murine Breast Cancer, Brandon Sturgill

Graduate Theses and Dissertations

Twist transcription factor is often overexpressed in aggressive tumors. Although needed in early embryonic development for organogenesis, Twist is known to induce an epithelial to mesenchymal transition in cells. In cancer, epithelial to mesenchymal transitions can lead to increased motility and invasiveness. It has also been linked to metabolic reprogramming and increased metastatic risk. Furthermore, metabolic preferences can increase proliferation, enhance metastatic potential, and influence the site of metastasis. We hypothesize that Twist directly affects the metabolism of cancer cells. We expect to see in vivo what we have seen in vitro; Twist overexpression should promote a shift away from …

Controlling Strain Energy Density In 3d Cellular Collagen Constructs During Complex Loads, Katherine Hollar

Boise State University Theses and Dissertations

Mechanical stimulation applied to damaged soft tissues, such as ligament, can promote tissue remodeling to accelerate healing. To help identify treatments that encourage ligament healing, bioreactors have been designed to subject 3D cellularized constructs to various loading conditions in order to determine the mechanical mechanisms that trigger cell-mediated repair. An innovative approach is to use a bioreactor to apply controlled states of biaxial stress to study the effects of strain energy density and distortion energy on cell activity. Tissue distortion has been linked to changes in the structure and function of ligament, yet the specific impact of distortion energy on …

Synthesis And Secretome Release By Human Bone Marrow Mesenchymal Stem Cell Spheroids Within Three-Dimensional Collagen Hydrogels: Integrating Experiments And Modelling, Jyotsna Joshi, Mohammadreza Dehghan Abnavi, Chandrasekhar R. Kothapalli

Chemical & Biomedical Engineering Faculty Publications

Myocardial infarction results in loss of cardiac cell types, inflammation, extracellular matrix (ECM) degradation, and fibrotic scar. Transplantation of bone marrow-derived mesenchymal stem cells (BM-MSCs) is being explored as they could differentiate into cardiomyocyte-like cells, integrate into host tissue, and enhance resident cell activity. The ability of these cells to restore lost ECM, remodel the inflammatory scar tissue, and repair the injured myocardium remains unexplored. We here elucidated the synthesis and deposition of ECM (e.g., elastin, sulfated glycosaminoglycans, hyaluronan, collagen type III, laminin, fibrillin, lysyl oxidase, and nitric oxide synthases), matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), and other secretome …

Design Of Cell-Instructive Biomaterial Scaffolds For Intervertebral Disc Regeneration, Nadia Sharma

Electronic Thesis and Dissertation Repository

Biomaterials-based therapies targeting the nucleus pulposus (NP) have the potential to promote regeneration and restore mechanical function to the intervertebral disc. This study developed composite hydrogels incorporating decellularized NP (DNP) and assessed its effects on viability, retention and differentiation of U-CH1 cells, an NP progenitor-like cell line. A minimal protocol was developed to decellularize bovine NP that reduced nuclear content while preserving key extracellular matrix components predicted to be favourable for bioactivity. The resulting DNP demonstrated cell-instructive effects, supporting U-CH1 viability and retention within the hydrogels, and promoted the differentiation of the progenitor-like cells towards an NP-like phenotype. These studies …

Formation Of A Vascular Regenerative Microenvironment Within Implantable Human Decellularized Adipose Tissue Bioscaffolds, Christopher Leclerc

Electronic Thesis and Dissertation Repository

Cellular therapies targeted at stimulating therapeutic angiogenesis in individuals with critical limb ischemia (CLI) have been under intense investigation. Hematopoietic progenitor cells (HPC) derived from umbilical cord blood have been previously shown to support limb revascularization in animal models of CLI, despite limited cell survival at the site of ischemia. This study attempted to improve HPC survival after transplantation and prolong pro-angiogenic function using human decellularized adipose tissue (hDAT) as a novel cell delivery platform. Compared to HPC conventionally grown on tissue-cultured plastic, hDAT scaffolds were shown to promote viability and proliferation of seeded HPC, and had cell- instructive effects …

Design, Construction And Application Of A Home-Built, Two-Photon Microscope, William P. Breeding

Electronic Theses and Dissertations

Two-photon microscopy (TPM) is a powerful, versatile imaging modality for the study of biological systems. This thesis overviews the relevant physics involved in TPM, design considerations and process of constructing a home-built, two-photon microscope, and provides a set of procedures to operate the system. Furthermore, this work explores several applications of TPM through the study of single-cell metabolism and imaging the cellular-material interface. Explored in particular depth was the imaging of cellulose nanofiber (CNF) materials, with the goal of understanding the three-dimensional nature of fibroblast cell growth when embedded within the materials. This work uncovered several optical properties of CNF, …

Identifying Extracellular Matrix Protein Turnover Rates For Tissue Engineers, Alita F. Miller

The Journal of Purdue Undergraduate Research

No abstract provided.

Genome-Edited Animals Are Not Transgenic Animals: Moving Toward Responsible Research And Innovation With New Biotechnologies, Yvie Yao

Minnesota Journal of Law, Science & Technology

No abstract provided.

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 …

Investigation Of The Effect Of Age On Regenerative Outcomes Following Treatment Of Volumetric Muscle Loss Injuries, John Taehwan Kim

Graduate Theses and Dissertations

Volumetric muscle loss (VML) is a traumatic injury in skeletal muscle resulting in the bulk loss of more than 20% of the muscle’s volume. Included in the bulk loss of muscle is the skeletal muscle niche comprised of nerve bundles, vasculature, local progenitor cells, basal lamina, and muscle fibers, overwhelming innate repair mechanisms. The hallmark of VML injury is the excessive accumulation of non-contractile, fibrotic tissue and permanent functional deficits. Though predominant in the younger demographic, the elderly population is also captured within VML injuries. There are many factors that change with aging in skeletal muscle that may further hinder …

A Study Of Protein And Peptide-Directed Nanoparticle Synthesis For Catalytic Materials, Abdollah Mosleh

Graduate Theses and Dissertations

Nanoparticles have received much attentions due to their unique properties that makes them suitable candidates for a broad range of applications. As the size of particles decreases, their surface area-to-volume ratio would increase which is the main cause of much attention. In addition to the size, their morphologies and compositions may also play important roles for defining unique properties. Nanoparticle synthesis include both bottom-up and top-down strategies. To control the process of inorganic nanoparticles synthesis one could follow the bottom-up approach to have atom-level control over their compositions, morphologies, phases, and sizes which is the subject of this work. Due …

Generation Of A Ccl2 Knockout Using Crispr/Cas9 And Lipid Mediated Transfection In Ct-26 Murine Colon Carcinoma Cells, Emma Sullivan

Biomedical Engineering Undergraduate Honors Theses

CCL2 is an inflammatory mediator that is released by tumor cells to activate and direct immune cell species, especially macrophages, to inflammatory sites within the body. The goal of this project was to successfully generate knockout the CCL2 ligand gene using a CRISPR/Cas9 complex delivered via lipid mediated transfection. The sgRNA and Cas9 mRNA were introduced into the cells via lipid-mediated transfection. The cells were incubated for 4 days, before being analyzed using PCR and gel electrophoresis. We expected to see one band on the first gel and two bands on the second gel. Two bands appeared on the first …

Bioengineering Extracellular Matrix Scaffolds For Volumetric Muscle Loss, Kevin Roberts

Graduate Theses and Dissertations

Volumetric muscle loss overwhelms skeletal muscle’s ordinarily capable regenerative machinery, resulting in fibrosis and severe functional deficits which have defied clinical repair strategies. My work spans the design and preclinical evaluation of implants intended to drive the cell community of injured muscle toward a regenerative state, as well as the development of an understanding of the molecular responses of this cell community to biomaterial interventions. I demonstrate a new class of biomaterial by leveraging the productive capacity of sacrificial hollow fiber membrane cell culture; I show specifically that unique threads of whole extracellular matrix can be isolated by solvent degradation …

Visualizing Ischemic Skin Flap Necrosis Through Phasor Analysis Of Autofluorescence Lifetime Images, Hallie Ramser Toomer

Graduate Theses and Dissertations

Necrotic skin flaps are difficult to predict and treat due to the lack of quantitative biomarkers. Label-free multiphoton microscopy is well suited for non-invasively monitoring skin metabolism through NAD(P)H and other intrinsic fluorophores, and offers immediate future directions for assessing necrosis in the clinic. The objective of this study was to assess whether phasor FLIM could be used to evaluate skin flap status and treatment efficacy in ex vivo skin sections. Phasor maps revealed differences in growth factor treatment and region, but changes in skin flap autofluorescence at 755nm excitation and 460nm emission were not just related to NAD(P)H. A …

Tauopathies, Novel Optogenetic Tools, And The Future Of Artificial Intellience In Medicine., Jessica L. Binder

Biomedical Sciences ETDs

To this day, there is no cure for Alzheimer’s disease (AD) and related dementias (ADRD). With the daunting rise at an exponential rate of ADRD burden and related deaths, the necessity to find a new line of attack is vital. Pathological accumulation of microtubule associated protein tau in neurons is a major neuropathological hallmark of Alzheimer’s disease (AD) and related tauopathies. Attempts have been made to promote clearance of pathological tau (p-Tau) from neurons via autophagy. Transcription factor EB (TFEB) has shown to clear p-Tau from neurons via autophagy. However, sustained TFEB activation and autophagy can create burden on cellular …

Bioproduction Of Adipic Acid Using Engineered Pseudomonas Putida Kt2440 From Lignin-Derived Aromatics, Howard Willett

Department of Chemical and Biomolecular Engineering: Theses and Student Research

Current industrial synthesis of adipic acid is nonrenewable and depends on a carcinogenic starting material, benzene. Biocatalysis with an engineered microorganism could turn a renewable feedstock into a value-added chemical such as adipic acid. Here we engineered P. putida KT2440 to transform lignin-derived aromatics, coumarate and ferulate, into adipic acid. Lignin is a recalcitrant plant biopolymer burned for thermal energy. Conversion of lignin into a value-added chemical will improve the efficiency of lignocellulose processing plants. The best performing engineered KT2440 strain produces 2.52 mM adipate at a 9.5% (mole/mole) yield. This was achieved by the genetic insertion of non-natural biosynthetic …

Accounting For Host Cell Protein Behavior In Anion-Exchange Chromatography, Ryan K. Swanson, Ruo Xu, Daniel S. Nettleton, Charles Glatz

Dan Nettleton

Host cell proteins (HCP) are a problematic set of impurities in downstream processing (DSP) as they behave most similarly to the target protein during separation. Approaching DSP with the knowledge of HCP separation behavior would be beneficial for the production of high purity recombinant biologics. Therefore, this work was aimed at characterizing the separation behavior of complex mixtures of HCP during a commonly used method: anion-exchange chromatography (AEX). An additional goal was to evaluate the performance of a statistical methodology, based on the characterization data, as a tool for predicting protein separation behavior. Aqueous two-phase partitioning followed by two-dimensional electrophoresis …

Developing A Control System To Better Understand The Effects Of Pyruvate Decarboxylase Activity On Clostridium Thermocellum Metabolism, Nicholas Cervenka

ENGS 88 Honors Thesis (AB Students)

In order for cellulosic biofuels from Clostridium thermocellum to be commercially viable, the ethanol yield and titer of the microbe must be increased. To accomplish this, it has been suggested to introduce the Pyruvate Decarboxylase (PDC) enzyme into C. thermocellum. In order to demonstrate effects on ethanol production by PDC prior to genetic modification, a cell free system (CFS) has been developed. A purified enzyme system was developed with the CFS to function as a control. Using the purified enzyme system, PDC from Saccharomyces cerevisiae was demonstrated to be a good candidate for further testing in the CFS.

Evaluation Of Human Umbilical Vein Endothelial Cells In Blood Vessel Mimics Through Changes In Gene Expression And Caspase Activity, Conor Charles Hedigan

Master's Theses

Blood vessel mimics (BVMs) are simple tissue engineered blood vessel constructs intended for preclinical testing of vascular devices. This thesis developed and implemented methods to characterize two of these components. The first aim of this thesis investigated the effect of cell culture duration and flow conditions on endothelial cell gene expression, especially regarding endothelial-to-mesenchymal transition (EndMT). A trend of decreased endothelial marker gene expression and increased mesenchymal marker gene expression would indicate EndMT. qPCR analysis revealed that increased cell culture duration did not result in EndMT, and in fact increased endothelial marker expression as cell culture duration increased. Disturbed flow …

Predicting Tgf-Β-Induced Epithelial-Mesenchymal Transition Using Data Assimilation, Mario J. Mendez, Matthew J. Hoffman, Elizabeth M. Cherry, Dr. Christopher Lemmon, Seth Weinberg

Biology and Medicine Through Mathematics Conference

No abstract provided.

The Effect Of Heterobifunctional Crosslinkers On Hema Hydrogel Modulus And Toughness, Elizabeth M. Boazak, Vaughn K. Greene Jr., Debra T. Auguste

Publications and Research

The use of hydrogels in load bearing applications is often limited by insufficient toughness. 2-Hydroxyethyl methacrylate (HEMA) based hydrogels are appealing for translational work, as they are affordable and the use of HEMA is FDA approved. Furthermore, HEMA is photopolymerizable, providing spatiotemporal control over mechanical properties. We evaluated the ability of vinyl methacrylate (VM), allyl methacrylate (AM), and 3-(Acryloyloxy)-2-hydroxypropyl methacrylate (AHPM) to tune hydrogel toughness and Young’s modulus. The crosslinkers were selected due to their heterobifunctionality (vinyl and methacrylate) and similar size and structure to EGDMA, which was shown previously to increase toughness as compared to longer crosslinkers. Vinyl methacrylate …

Using The Xenopus Developmental Eye Regrowth Stystem To Distinguish The Role Of Developmental Versus Regenerative Mechanisms, Cindy X. Kha, Dylan J. Guerin, Kelly Ai-Sun Tseng

Life Sciences Faculty Research

A longstanding challenge in regeneration biology is to understand the role of developmental mechanisms in restoring lost or damaged tissues and organs. As these body structures were built during embryogenesis, it is not surprising that a number of developmental mechanisms are also active during regeneration. However, it remains unclear whether developmental mechanisms act similarly or differently during regeneration as compared to development. Since regeneration is studied in the context of mature, differentiated tissues, it is difficult to evaluate comparative studies with developmental processes due to the latter’s highly proliferative environment. We have taken a more direct approach to study regeneration …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi S. Patel

University Scholar Projects

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Fabrication And Characterization Of Collagen-Polypyrrole Constructs Using Direct-Ink Write Additive Manufacturing, Rooshan Arshad

Electronic Thesis and Dissertation Repository

Current efforts in the tissue engineering field are being directed towards the creation of platforms which will facilitate in instructing cells towards biologically relevant outcomes such as stem cell differentiation and disease pathophysiology. Traditional fabrication methods serve as a limiting factor for the production of such platforms as they lack feature and geometric complexity. Additive Manufacturing (AM) offers advantage over said methods by affording designers creative freedom and great control over printed constructs. Such constructs can then be used to create appropriate models for study- ing a plethora of tissues and structures. An AM methodology for Direct-Ink Write (DIW) printing …

Comparing The Effects Of Fibroblast Growth Factors On Growth Rate Of Human Fibroblast Cell Lines, Tasha Repella

Biomedical Engineering Undergraduate Honors Theses

Numerous studies have demonstrated the usefulness of growth factors in medium formulations to promote proliferation and viability of human fibroblasts in laboratory settings. However, due to the differences in the source and age of fibroblasts, the ability of growth factors like hFGF1 to promote proliferation varies. Equally difficult is the ability of hFGF1 to promote proliferation of diseased fibroblasts due to complexities associated with specific mitochondrial diseases. In this context, we decided to evaluate the potential for novel hyper stable growth factors super hFGF and hFGF1 (shFGF and hFGF1 respectively), to contribute to proliferation of different normal and diseased fibroblasts. …

Investigating Virus Clearance Via Ph Inactivation During Biomanufacturing, Wenbo Xu

Biomedical Engineering Undergraduate Honors Theses

In the processing of biopharmaceuticals, viral clearance and viral safety are important for the development of monoclonal antibodies. Murine xenotropic leukemia virus (XMuLV) is one of the retroviruses, recommended by Food and Drug Administration (FDA) as a model virus for viral clearance via inactivation from therapeutics derived from Chinese hamster ovary cells (CHO). A robust and effective method was investigated to clear or inactivate endogenous viruses by low pH inactivation. The effects of different conductivity and inactivated time on XMuLV clearance was determined. Acetate buffer was prepared with different conductivity, and 2% XMuLV was spiked into acetate buffer. XMuLV virus …