Down-regulation of SK Channels Among Hypothalamic Paraventricular Nucleus Projecting Rostral Ventrolateral Medulla Neurons and Sympathetic Activation in AngII-Salt Hypertensive Rats
3:00 on Friday, December 9 in U113 M&M
Qinghui Chen, Asst. Professor, Kinesiology and Integrative Physiology
3:00 on Friday, December 2 in U113 M&M
Sean Kirkpatrick, Associate Professor and Chair, Biomedical Engineering
3:00 on Friday, November 4 in U113 M&M
Dr. Feng Zhao, Assistant Professor in the Department of Biomedical Engineering
3:00 on Friday, October 21 in U113 M&M
Xiaoqing Tang, Asst. Professor, Biological Sciences
Friday, September 30 at 3:00—U113 M&M Building
Bruce Lee, Asst. Professor, Biomedical Engineering
Bioadhesives have a wide range of important applications in the biomedical field. Tissue adhesives simplify complex surgical procedures to achieve effective wound closure and surgical repair. Despite these important functions, currently available adhesives seldom meet the basic requirements for in vivo applications because of possible disease transmission, poor adhesive quality, or toxicity concerns. Thus, there is an ongoing need for the development of tissue adhesives with improved characteristics. Nature provides many outstanding examples of adhesive strategies from which chemists and materials scientists can draw inspiration in their pursuit of new biomaterials. Of particular interest is the mussel adhesive protein (MAP) secreted by marine mussels. MAP is initially secreted as a proteinaceous fluid, and then subsequently harden in situ to form an adhesive plaque, which allow mussels to bind tenaciously to various types of sur- faces underwater. One of the unique structural features of MAP is the presence of L-3,4- dihydroxyphenylalanine (DOPA), an amino acid post-translationally modified from tyrosine, which is believed to fulfill the dual role as the adhesive moiety and the crosslinking precursor. My research had focused on the incorporation of DOPA and its derivatives in creating synthetic mimics of MAPs for various medical applications. In this seminar, I will discuss the design and application of these biomimetic adhesive materials.
Friday, September 16 at 3:00—U113 M&M Building
Niloy Choudhury, PhD, Department of Biomedical
It is important to measure sub-pixel motion in biological specimen as it allows us to investigate wide range of biological phenomenon ranging from micro-mechanical motion in tissue to estimating metabolic activity. Optical Coherence Tomography is one such technique that can provide images of sub-pixel motion with cellular level resolution (~10 μm). A Time Domain Optical Coherence Tomography (TD-OCT) based system has been developed to investigate “hearing mechanism” by measuring sub nanometer motion of the organ of Corti in a guinea pig. A 3-D optical micro-angiography system based on the principles of Fourier Domain Optical Coherence Tomography (FD-OCT) has also been developed. Combining the FD-OCT system with a novel imaging process allows us to achieve full depth of scan for structural and blood flow measurements. Using this novel device Micro-circulation in a gerbil cochlea is investigated as it is believed that a change in blood flow influences a number of cochlear diseases that can lead to
Wednesday, January 19
211 Chemical Sciences & Engineering Building
2:00 pm
Presenter: Zannatul Ferdous, Ph.D., Parker H. Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology
Abstract: My research uses unique model systems to study mechanisms and causes of cardiovascular diseases, particularly pathologies of heart valves. Valve diseases and defects are major causes of mortality in the elderly population and children in the US. Since altered expression of decorin has been observed in diseased heart valves, for my graduate research, the roles of proteoglycan decorin on extracellular matrix remodeling and tissue mechanics were investigated. Using tissueengineered collagen gels, we demonstrated that decorin-mediated matrix remodeling was heavily modulated by decorin-transforming growth factor beta (TGF-β) interaction. In addition, cyclic strain promoted compensatory behavior in collagen gels containing decorin-deficient cells, suggesting the influence of tissue mechanics on cellular function. We also showed the utility of a proper chemical and mechanical environment for studying ex vivo tissue systems. For my postdoctoral research, the contributions of mechanical forces to the initiation and progression of vascular and valvular calcification are being studied using cells isolated from non-sclerotic human tissues. We have observed that expression of osteogenic and matrix remodeling markers are dependent on both cell source (vascular versus valvular) and mechanical strain. In addition, calcification is observed to be modulated by the magnitude of strain (physiological versus pathological) applied to either cell types. We anticipate that the tissue-engineered model would help determine biomarkers for early detection and prevention of valve calcification. Additionally, the roles of microRNAs (miRNAs) in valvular diseases are also being investigated using RNAs isolated from endothelial cells in freshly isolated porcine valves. We hope that this research would lead to the discovery of important miRNAs and their roles in aortic valve biology and diseases. Continued research would therefore improve our knowledge of the complex heart valve environment and help determine treatment options for the large population of elderly and children in need for valve replacement.
Tuesday, January 11
U113 M&M Building
2:00 pm
Presenter: Feng Zhao, Ph.D., Department of Biomedical Engineering, Duke University
Abstract: The recreation of a natural microenvironment is of significant importance to realize the regeneration potential of cells for engineering functional tissues. My research aims to replicate the in vivo cell-cell and cell-environment interactions by manipulating biomaterials, oxygen tension, and hydrodynamic culture conditions in a precisely controlled manner. The current study focuses on tissue-engineering of scaffold-free small-diameter blood vessel using human mesenchymal stem cells (hMSCs) based on their unique antithrombogenic property, immunomodulatory ability, and pluripotency for differentiation into vascular phenotypes. The fulfillment of the therapeutic application of tissue-engineered blood vessel (TEBV) from hMSCs requires the cells to maintain high viability, organization, and stemness. By culturing hMSCs under the combined stimulation of nanotopographical cue and low oxygen tension, an extensively aligned cell sheet was fabricated with well-preserved stemness and viability. The physiologically low O2 (2%) tension significantly improved the confluency and extracellular matrix proteins secretion of the cells, which facilitated the process of cell sheet harvesting. The fabrication of a completely biological tubular structure was achieved by wrapping the aligned hMSC sheets around a temporary supporting mandrel. Maturation of the cellular construct in the rotating wall bioreactor reinforced its mechanical stability and allowed its development into an implantable small-diameter TEBV. The preliminary animal study in a rat femoral artery model demonstrated the remodeling of the vascular graft as well as the infiltration of endothelial cells into the hMSC-based TEBV.
Friday, December 3
U113 M&M Building
11:00 am
Presenter: Li Yao, Ph.D., National Center for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
Abstract: Advances in neuroscience over the past two decades begin to offer hope for patients with injury in nervous system. Since the demonstration in 1980 that central nervous system axons have the capacity to regenerate within peripheral nervous system graft, much has been accomplished toward understanding factors that contribute to a physiologically permissive environment. Axonal regeneration after injury or disease is the major challenge in both peripheral and central nervous system. Neural engineering is a promising approach for axonal regeneration by preventing inhibitory factors and enhancing guided axonal growth. In peripheral nerve regeneration, neural conduits have been investigated to bridge nerve defects. In our recent study, the advance in the design of engineered scaffolds that mimic peripheral nerve multiple basal lamina have improved guided axonal regeneration in vivo. Despite recent advances, the limited demonstration of functional improvement in in vivo models of spinal cord injury has prevented advancement of regenerative therapy to clinical use. This may be due in large part to the multifaceted nature of spinal cord injuries, which presents a major challenge to therapeutic development. In order for viable treatment strategies to be realized clinically, it is likely that combinations of current therapeutic approaches must be used. We are developing a functionalised graft that targets injury mechanisms at the molecular, cellular and tissue levels of spinal cord injury. Biodegradable polymers can simultaneously provide structural guidance at a cellular level and a reservoir for sustained gene delivery. This integrative approach suggests a possible treatment strategy and may serve as an in vivo model for studying optimisation of various combinations of treatments. Effectively directed neuron migration is critical for development and repair in the central nervous system. Endogenous electrical signals are present in many developing systems and crucial cellular behaviours such as neuronal cell division, cell migration and cell differentiation are all under the influence of such endogenous electrical cues. Pre-clinical in vivo studies have used electric fields to attempt to enhance re-growth of damaged spinal cord axons with some success. We recently demonstrated that small electric fields not only guide axonal growth, but also can direct the earlier events of neuronal migration and neuronal cell division. This raises the possibility that applied or endogenous electric fields, perhaps in combination, may direct transplanted neural stem cells, or regenerating neurons, to the desired site after brain injury or neuron degeneration. The high complexity of both structure and function of the central nervous system however, poses significant challenges to techniques for applying electric fields to promote neurogenesis. The evolution of functional biomaterials and nanotechnology may provide promising solutions for the application of electric fields in guiding neuron migration in neurogenesis within the central nervous system.
Friday, October 8 at 3:00 – Room U113 M&M Bldg. Andrew E. Anderson, PhD, University of Utah.
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