Molecular, Cellular, and Tissue Engineering Commons^™

Development And Implementation Of Assessment Methods For Tissue-Engineered Blood Vessel Mimics, Tanner Stevenson

Biomedical Engineering

Coronary Artery Disease (CAD), the most prevalent form of heart disease, is the result of clogged or damaged coronary arteries and claims around 380,000 Americans annually. A common treatment for CAD involves placing a stent into the artery in order to open the lumen and support the native tissue—a procedure that drastically reduces patient recovery times in comparison to heart bypass surgery. However, stents do not always interact well with the body and require additions such as surface coatings or drug elution in order for additional biocompatibility. These additions necessitate extensive in vitro and in vivo testing which are expensive …

Functional Vasodilation Is Impaired In Arterialized Capillaries In The Spinotrapezius, Joshua P. Cutts

Biomedical Engineering

Ischemic diseases are the result of atherosclerotic plaques, which occlude conduit arteries. Ischemic disease in different tissues leads to different conditions, such as coronary artery disease (CHD), cerebrovascular disease (CVD), and peripheral arterial occlusive disease (PAOD). Patient vasculature architecture is variable; some patients having many collateral vessels, which are connect one arterial branch to another, and readily serve as natural bypass routes to atherosclerotic occlusions, to enlarge and provide blood flow to tissue distal to the occlusion. Patients with many natural collateral vessels are ischemia protected. Unfortunately, not all patients have collateral arterioles to remodel into conduit vessels and provide …

Developing Defined And Scalable 3d Culture Systems For Culturing Human Pluripotent Stem Cells At High Densities, Yuguo Lei, Daeun Jeong, Jifang Xiao, David V. Schaffer

Department of Chemical and Biomolecular Engineering: Faculty Publications

Human pluripotent stem cells (hPSCs)—including embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs)—are very promising candidates for cell therapies, tissue engineering, high throughput pharmacology screens, and toxicity testing. These applications require large numbers of high quality cells; however, scalable production of human pluripotent stem cells and their derivatives at a high density and under well-defined conditions has been a challenge. We recently reported a simple, efficient, fully defined, scalable, and good manufacturing practice (GMP) compatible 3D culture system based on a thermoreversible hydrogel for hPSC expansion and differentiation. Here, we describe additional design rationale and characterization of this …

Fluid Flow-Induced Mesenchymal Stem Cell Migration: Role Of Fak And Rock Mechanosensors, Brandon D. Riehl

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The study of mesenchymal stem cell (MSC) migration under mechanical stimulation conditions with investigation of the underlying molecular mechanism could lead to a better understanding and outcomes in stem cell-based regenerative medicine. MSCs having multipotent regenerative capability exist in niches in the bone marrow, muscle, vasculature, and in other tissues throughout the body, and their migration through tissues and vasculature for the repair of damaged tissue is a key process of cell and tissue homeostasis, remodeling, and regeneration. While cell migration in response to cytokines and other chemo-attractants is relatively well understood, little is revealed in regard to the effect …

Application Of Limited Mixing In The Hele–Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

Results …

Temporal Modulation Of Plasma Species In Atmospheric Dielectric Barrier Discharges, Aijun Yang, Xiaohua Wang, Dingxin Liu, Mingzhe Rong, Michael G. Kong

Bioelectrics Publications

The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature and the moment of maximum species densities is almost consistent with peak discharge current density. In this paper, a one-dimensional fluid model is used to investigate the temporal structure of plasma species in an atmospheric He-N₂ dielectric barrier discharge (DBD). It is demonstrated that there exist microsecond delays of the moments of the maximum electron and ion densities from the peak of discharge current density. These time delays are caused by a competition between the electron impact and Penning ionizations, modulated by the N_{2 …}

Analysis And Modeling Of The Roles Of Actin-Myosin Interactions In Bladder Smooth Muscle Biomechanics, Seyed Omid Komariza

Theses and Dissertations

Muscle mechanical behavior potentially plays an important role in some of the most common bladder disorders. These include overactive bladder, which can involve involuntary contractions during bladder filling, and impaired contractility or underactive bladder, which may involve weak or incomplete contractions during voiding. Actin-myosin cross-bridges in detrusor smooth muscle (DSM) are responsible for contracting and emptying the bladder. The total tension produced by muscle is the sum of its preload and active tensions. Studies suggest that actin-myosin cross-links are involved in adjustable preload stiffness (APS), which is characterized by a preload tension curve that can be shifted along the length …

Bioengineered Hearts, Rivky Loeb

The Science Journal of the Lander College of Arts and Sciences

Heart disease is one of the highest causes for fatality in the world. Although many such diseases can be treated by a heart transplant, this in itself can cause countless problems. Aside from the high demand for donor hearts, there is the risk of the patient’s immune system rejecting the transplanted heart. A bioengineered heart would reduce the need for donor hearts, and thus save countless lives. Finding a suitable scaffold, obtaining appropriate cells, and ensuring that the tissue will function properly are the main focuses in creating an artificial heart. While most of the studies done have been concentrated …

Bioerodible Calcium Sulfate Bone Grafting Substitutes With Tailored Drug Delivery Capabilities, Bryan R. Orellana

Theses and Dissertations--Biomedical Engineering

Bone regeneration or augmentation is often required prior to or concomitant with implant placement. With the limitations of many existing technologies, a biologically compatible synthetic bone grafting substitute that is osteogenic, bioerodible, and provides spacing-making functionality while acting as a drug delivery vehicle for bioactive molecules could provide an alternative to ‘gold standard’ techniques.

In the first part of this work, calcium sulfate (CS) space-making synthetic bone grafts with uniformly embedded poly(β-amino ester) (PBAE) biodegradable hydrogel particles was developed to allow controlled release of bioactive agents. The embedded gel particles’ influence on the physical and chemical characteristics of CS was …

Evaluation Of Tissue-Engineered Tendon Enthesis Polymer Constructs, Joshua A. Bundy Bs, Mary Beth Wade Phd, Hitomi Nakao Md, Phillip Mcclellan Phd, Qing Yu Phd, Robin Jacquet-Childs Ms, William J. Landis Phd

Williams Honors College, Honors Research Projects

Both scientists and clinicians have proposed tissue engineering as the future of medicine. The possibilities for tissue engineering, that is, fabrication of tissues and organs in the laboratory and their translation to patients, appear to be endless, and many believe that this new approach in medicine will result in abolishing many common ailments, injuries, and congenital defects. Injuries to a tendon enthesis, the normal tissue connection between tendon and bone, are of particular concern to clinicians because of their frequency and failure to repair as a result of surgery. While these injuries may not be life threatening, they can certainly …

Tissue Engineering Scaffold Fabrication And Processing Techniques To Improve Cellular Infiltration, Casey Grey

Theses and Dissertations

Electrospinning is a technique used to generate scaffolds composed of nano- to micron-sized fibers for use in tissue engineering. This technology possesses several key weaknesses that prevent it from adoption into the clinical treatment regime. One major weakness is the lack of porosity exhibited in most electrospun scaffolds, preventing cellular infiltration and thus hosts tissue integration. Another weakness seen in the field is the inability to physically cut electrospun scaffolds in the frontal plane for subsequent microscopic analysis (current electrospun scaffold analysis is limited to sectioning in the cross-sectional plane). Given this it becomes extremely difficult to associate spatial scaffold …

Physiological And Transcriptional Memory In Guard Cells During Repetitive Dehydration Stress, Laetitia Virlouvet, Michael E. Fromm

Nebraska Center for Biotechnology: Faculty and Staff Publications

Arabidopsis plants subjected to a daily dehydration stress and watered recovery cycle display physiological and transcriptional stress memory. Previously stressed plants have stomatal apertures that remain partially closed during a watered recovery period, facilitating reduced transpiration during a subsequent dehydration stress. Guard cells (GCs) display transcriptional memory that is similar to that in leaf tissues for some genes, but display GC-specific transcriptional memory for other genes. The rate-limiting abscisic acid (ABA) biosynthetic genes NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) and ALDEHYDE OXIDASE 3 (AAO3) are expressed at much higher levels in GCs, particularly during the watered recovery interval, relative to their low …

The Pseudomonas Syringae Type Iii Effector Hopd1 Suppresses Effector-Triggered Immunity, Localizes To The Endoplasmic Reticulum, And Targets The Arabidopsis Transcription Factor Ntl9, Anna Block, Tania Y. Toruno, Christian G. Elowsky, Chi Zhang, Jens Steinbrenner, Jim Beynon, James R. Alfano

Nebraska Center for Biotechnology: Faculty and Staff Publications

Pseudomonas syringae type III effectors are known to suppress plant immunity to promote bacterial virulence. However, the activities and targets of these effectors are not well understood. We used genetic, molecular, and cell biology methods to characterize the activities, localization, and target of the HopD1 type III effector in Arabidopsis. HopD1 contributes to P. syringae virulence in Arabidopsis and reduces effector-triggered immunity (ETI) responses but not pathogen-associated molecular pattern-triggered immunity (PTI) responses. Plants expressing HopD1 supported increased growth of ETI-inducing P. syringae strains compared with wild-type Arabidopsis. We show that HopD1 interacts with the membrane-tethered Arabidopsis transcription factor NTL9 and …

Synthesis And Characterization Of Nucleic Acid-Functionalized Nanomaterials, Brianna S. Carroll, Jong Hyun Choi

The Summer Undergraduate Research Fellowship (SURF) Symposium

Motor proteins such as kinesin move along microtubules in order to transport cellular cargos throughout the cell by obtaining energy from RNA hydrolysis which allows the cell to complete the tasks needed to stay alive. In this work, we developed synthetic molecular motors using DNA enzymes (DNAzyme) and fluorescent nanomaterials which mimic the functions and structures of motor proteins. A DNAzyme-capped CdS nanoparticle and a RNA-functionalized single-walled carbon nanotube (SWCNT) were used as a walker and a track in the motor platform, respectively. As a walking mechanism, the DNAzyme cleaved the RNA substrates in the presence of metal cations. The …

Inkjet Printing Of Polarized Yeast Cells, Xiuyuan Yang, Kari Clase

The Summer Undergraduate Research Fellowship (SURF) Symposium

The motivation is to applying engineering knowledge to develop 3D bio-printing in inkjet printer (first stage--monolayer). To achieve the goal, there are three problems to solve. First, we have to figure out regulation of growth of target cells; inability to regulate the location and pattern of growing cells make us even unable to build 3D printer in the direct way. Second problem is how to protect of yeast cells from high temperature and viscous force when printing. The third issue is how to modify the inkjet printer especially the feeding system in order to implement printing on other materials rather …

Adhesive Elastomeric Proteins, Haefa Mansour, Julie Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Sutures and staples commonly used to close surgical wounds tend to be much stiffer than the surrounding tissue, often resulting in external tissue damage. Surgical adhesives provide a promising alternative to these sutures and staples. Ideal surgical adhesives are biocompatible, able to set well and remain sticky in moist conditions, possess strong adhesive and cohesive properties, and exhibit mechanical properties that mimic those of the surrounding tissue. Unfortunately, the adhesives available today are unable to satisfactorily meet all of these criteria. We are utilizing protein engineering techniques to design, create, and test a new surgical adhesive that combines the adhesive …

Synthetic Polymeric Carbohydrates Recognized Toxoplasma Gondii Tachyzoites And Induced Early Phagocytosis By Macrophages, Souzan Hussain Eassa

Theses and Dissertations

Toxoplasmosis is a parasitic disease caused by the intracellular protozoan Toxoplasma gondii your words (T. gondii your words) that affects most types of warm-blooded vertebrate cells. Up to one third of the humans population in the world is chronically infected by this parasite. Human and animals at risk for toxoplasmosis include fetuses, newborns, and immunologically impaired patients. To date, there is no vaccine available and no drug has a successful effective against chronic form of toxoplasmosis. Recent Toxoplasma your words diagnostic methods showed high false positive results and cannot detect the parasite in the early infection stage. Early diagnosis of …

Method And Apparatus For Electrical Stimulation Of Tissues Using Signals That Minimize The Effects Of Tissue Impedance, Jeffrey Hargrove

Mechanical Engineering Patents

A tissue stimulation system that generates an electrical tissue stimulation signal configured to reduce tissue impedance and increase depth of signal penetration. The use of leads is dynamically controlled and altered between conducting biopotential voltages, conducting electrical tissue stimulation signals, and grounding, in response to a computational analysis of biopotential data acquired from a region of tissue to be stimulated.

Zein: Novel Natural Polymer For Nanoparticle- And Film-Mediated Gene Delivery, Jessica D. Taylor

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Gene delivery, the introduction of DNA into cells, is applicable to gene therapy, DNA vaccination, functional genomics and diagnostics, tissue engineering, and drug-eluting medical devices. Particulates incorporating DNA are promising vehicles for gene delivery and overcome some of the barriers that hinder successful gene transfer, with the ability to protect DNA and provide for controlled, localized, and sustained release and transfection. Furthermore, innovative new gene delivery strategies that incorporate DNA particulates or complexes within films or coatings for devices and scaffolds could further provide for controlled and sustained transfection at the site of implant. Zein, a hydrophobic protein from corn, …