RESUMO
Polymeric materials have been used to realize optical systems that, through periodic variations of their structural or optical properties, interact with light-generating holographic signals. Complex holographic systems can also be dynamically controlled through exposure to external stimuli, yet they usually contain only a single type of holographic mode. Here, we report a conjugated organogel that reversibly displays three modes of holograms in a single architecture. Using dithering mask lithography, we realized two-dimensional patterns with varying cross-linking densities on a conjugated polydiacetylene. In protic solvents, the organogel contracts anisotropically to develop optical and structural heterogeneities along the third dimension, displaying holograms in the form of three-dimensional full parallax signals, both in fluorescence and bright-field microscopy imaging. In aprotic solvents, these heterogeneities diminish as organogels expand, recovering the two-dimensional periodicity to display a third hologram mode based on iridescent structural colours. Our study presents a next-generation hologram manufacturing method for multilevel encryption technologies.
RESUMO
The aim of this study was to track the migration of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) administered through a single intravenous injection and to observe the consequential therapeutic effects in a transgenic Alzheimer's disease mouse model. Ten-month-old APP/PS1 mice received a total injection of 1×10 cells through the lateral tail vein and were killed 1, 4, and 7 days after administration. On the basis of immunohistochemical analysis, hUCB-MSCs were not detected in the brain at any of the time points. Instead, most of the injected mesenchymal stem cells were found to be distributed in the lung, heart, and liver. In terms of the molecular effects, statistically significant differences in the amyloid ß protein, neprilysin, and SOX2 levels were not observed among the groups. On the basis of the results from this study, we suggest that single intravenously administered hUCB-MSCs are not delivered to the brain and also do not have a significant influence on Alzheimer's disease pathology.
