Directed cell migration is critical to a variety of biological and physiological processes. Although simple topographical patterns such as parallel grooves and three-dimensional post arrays have been studied to guide cell migration, the effect of the dimensions and shape of micropatterns, which respectively represent the amount and gradient of physical spatial cues, on cell migration has not yet been fully explored. This motivates a quantitative characterization of cell migration in response to micropatterns having different widths and divergence angles. The changes in the migratory (and even locational) behavior of adherent cells, when the cells are exposed to physical spatial cues imposed by the micropatterns, are explored here using a microfabricated biological platform, nicknamed the "Rome platform". The Rome platform, made of a biocompatible, ultraviolet (UV) curable polymer (ORMOCOMP), consists of 3 μm thick micropatterns with different widths of 3 to 75 μm and different divergence angles of 0.5 to 5.0°. The migration paths through which NIH 3T3 fibroblasts move on the micropatterns are analyzed with a persistent random walk model, thus quantifying the effect of the divergence angle of micropatterns on cell migratory characteristics such as cell migration speed, directional persistence time, and random motility coefficient. The effect of the width of micropatterns on cell migratory characteristics is also extensively investigated. Cell migration direction is manipulated by creating the gradient of physical spatial cues (that is, divergence angle of micropatterns), while cell migration speed is controlled by modulating the amount of them (namely, width of micropatterns). In short, the amount and gradient of physical spatial cues imposed by changing the width and divergence angle of micropatterns make it possible to control the rate and direction of cell migration in a passive way. These results offer a potential for reducing the healing time of open wounds with a smart wound dressing engraved with micropatterns (or microscaffolds).
In this study, ultra-thin ion exchange film on the ceramic supporter (UTFCS) composed of thin polymer layer and nanoporous ceramic layer with low electrical resistance was developed. The electrical properties and permselectivity of UTFCSs were evaluated and the properties of UTFCSs were compared with other ion exchange membranes. Fabricated UTFCSs were applied to a reverse electrodialysis (RED) system to evaluate the output characteristics and compared with other ion exchange membranes. The power density of RED using UTFCS was 36.6 mW/m2, which was 8% higher than that of a commercial anion exchange membrane. In addition, possibility as power source was experimentally verified by driving LEDs. The proposed UTFCS can be applied not only to RED but also to energy development such as fuel cells and microbial cells.
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