BNG Presentation by Dr. Soonjo Kwon

The lungs are subject to injury by many mechanisms. The injury may be related to a chronic disease such as asthma and environmental toxicants. Each of the injuries can be classified by a frequency (e.g., repetitive) and a character (e.g., mechanical stresses, environmental toxicants, etc.). Human lung epithelial cells serve as a barrier at the interface between the surrounding air and our body in response to external perturbations, such as physical denudation, compressive and tensional stresses, and exogenous particles. Monolayer culture of the key individual cell types of the lung has provided abundant fundamental information on the response of these cells to external perturbations. However, such systems are limited by the absence of cell-cell interactions and their dynamic nature, which are both present in vivo. We characterized the response of the engineered lung tissue to a physical denudation and compressive stress wound to the epithelium that mimics the pattern observed in asthma and demonstrated the possible application to health risk assessment of human exposure to air pollutants and nano-particles. We suggested two viable alternatives to in vivo models to evaluate the health risk of human exposure to external perturbation.

In addition to mimicking structure and dynamic nature of the tissues, we are also interested in the effects of material properties and mechanical stress fields on the specific functions of the tissues of interest. All cells or tissues are exposed to specific microenvironments that are generated locally at the micro- or nano-scale level by cell–cell, cell-soluble factor, or cell–extracellular matrix interactions which influences cell functions in their tissues. Especially, each cell type is specifically tuned to the specific microenvironments in which it resides. Neural cell growth, survival and differentiation are favored by a highly compliant matrix. In contrast to neural cells, osteoblast differentiation and survival occurs preferentially on stiffer extracellular matrices. As a preliminary experiment, we incorporated different concentrations and multi-walled carbon nanotubes (MWCNTs) into reconstituted type I collagen, and evaluated proliferation, differentiation, and mineralization of mesenchymal stem cells (MSCs) on these MWCNT-collagen scaffolds. MWCNTs were strongly entrapped in collagen at MWCNT concentrations below 100 ppm. Alkaline phosphatase (AP) activity and mineralized nodules of extracellular matrix (ECM) were monitored as osteogenic differentiation markers. MWCNT-collagen scaffolds induced significantly higher level of AP activity than collagen scaffold and increased ECM mineralization 12 days after replacement with differentiating media. The increase in MSC differentiation and mineralization may be due to the increased stiffness and tensile strength of MWCNT-collagen scaffolds.

BIO:
Dr. Soonjo Kwon earned his Ph.D. in the Department of Chemical Engineering and Materials Science at the University of California, Irvine. He was postdoctoral fellow in the Department of Bioengineering in the University of California, San Diego.

Currently, he is an assistant professor in the Department of Biological Engineering at the Utah State University (USU). His current research activities focus on Cellular Engineering, Tissue Engineering, and Cellular Biomechanics. He has been a principle investigator on grants totaling over $1.2 million from federal, state, and industry. He has published more than 24 peer reviewed journal articles with over 55 conference papers and presentations. He has 10 year experience on teaching both science and engineering undergraduate and graduate courses. He has received the Teaching Excellence Award, Outstanding Graduate Mentor Award, and Performance Excellence Award.