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[생체공학 부문] Shapes, Motions, and Forces in Cells
Jennifer H. Shin(신현정) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월
Cells in our body sense and respond to mechanical stimuli to regulate their physiological processes. These mechanical forces are exogenously imposed by various factors from the microenvironment of the tissue, regulating the biological responses of the cells. While normal cells in our body possess their own response strategies against moderate physicochemical stresses for homeostasis, pathological responses may be initiated to prompt disease conditions when the stress level falls below or goes above a critical threshold. Despite the importance of mechanical stresses in cellular physiology and pathology, the current focus of medicine largely ignores the physical basis of diseases. Pathological conditions such as cancer can be induced by an abnormality in the physical microenvironment, and the physical state of the cells can regulate their metastatic fate in the tumor mass. To understand the physiological behavior of the cells, it is crucial to develop pathologically relevant cell-based in vitro experimental models. In this work, we developed 2D and 3D cell-based models to visualize how stresses between adjacent cells and those between cells and the environment are produced in the clusters and how these stresses dictate the shapes and motions of the constituent cells. For quantitative analyses, we utilized particle image velocimetry (PIV), traction force microscopy (TFM), and monolayer stress microscopy (MSM) along with conventional biochemical assays and other phenotyping tools. We identified the active remodeling of stresses during the rearrangement of cell clusters. Using the simple 2D model, we unraveled the correlation among the shapes, motions, and physical stresses of the cells. In the context of cancer metastasis, we first identified the key factors that actively regulated the formation of the cellular aggregates and quantified the physical forces that would prevent the dissemination from occurring in the aggregates.
EFFECTS OF UNIFORM SHEAR STRESS ON THE MIGRATION OF VASCULAR ENDOTHELIAL CELL
신현정(Jennifer H. Shin),송석현(Sukhyun Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
The migration and proliferation of vascular endothelial cells (VEC), which play an important role in vascular remodeling, are known to be regulated by hemodynamic forces in the blood vessels. When shear stresses of 2, 6, 15 dynes/㎠ are applied on mouse micro-VEC in vitro, cells surprisingly migrate against the flow direction at all conditions. While higher flow rate imposes more resistance against the cells, reducing their migration speed, the horizontal component of the velocity parallel to the flow increases with the flow rate, indicating the higher alignment of cells in the direction parallel to the flow at a higher shear stress. In addition, cells exhibit substrate stiffness and calcium dependent migration behavior, which can be explained by polarized remodeling in the mechanosensitive pathway under shear stress.
신현정(Jennifer H. Shin),김기중(Kijung Kim),한제현(Jehyun Han),박진성(Jin-Sung Park),박상후(Sanghoo Park),최원호(Wonho Choe) 한국가시화정보학회 2015 한국가시화정보학회 학술발표대회 논문집 Vol.2015 No.12
In this study, DBD (Dielectric Barrier Discharge) atmospheric pressure plasma source was utilized to deactivate wild type Salmonella strain. The bacterial motility was quantified based on the MSD (mean square displacement) to map the areal expansion of the moving bacteria. Also, to identify the relationship between motility and infectious activity of wild type Salmonella strain, the viability of the MCF-10A cells was accessed after the plasma-treated bacteria were co-incubated with the mammalian cells. The results show that the plasma treatment of as low as 10 seconds significantly reduces the motility of bacteria and the reduced motility correlates directly with the suppressed bacterial infection into the host cells.