Suppressing ROS Production\nof AIE Nanoprobes by Simple\nMatrices Optimization for CNS Cell Observation and Minimized Influence\nof Cytoskeleton Morphology

The visualization of the central nervous system (CNS)\nhas proposed\nstringent criteria for fluorescent probes, as the inevitable production\nof reactive oxygen species (ROS) or heat generated from most photoluminescent\nprobes upon excitation can disturb the normal status of relatively\ndelicate CNS cells. In this work, a red-emitting fluorogen with aggregation-induced\nemission (AIE) characteristics, known as DTF, was chosen as the model\nfluorogen to investigate whether the side effects of ROS and heat\ncould be suppressed through easy-to-operate processes. Specifically,\nDTF was encapsulated with different amphiphilic matrices to yield\nAIE nanoprobes, and their photoluminescent properties, ROS production,\nand photothermal conversion rates were examined. BSA@DTF NPs possessed\n1.3-fold brightness compared to that of DSPE-PEG@DTF NPs and F127@DTF\nNPs but its ROS generation efficiency is markedly decreased to only\n2.4% of that produced by F127@DTF NPs. Meanwhile, BSA@DTF NPs showed\na negligible photothermal effect. These features make BSA@DTF NPs\nfavorable for long-term live cell imaging, particularly for fluorescent\nimaging of CNS cells. BSA@DTF NPs were able to sustain the normal\nstate of HT-22 neuronal cells with continuous illumination for at\nleast 25 min, and they also preserved the cytoskeleton of microglia\nBV-2 cells as the untreated control group. This work represents a\nsuccessful but easy-to-operate process to suppress the ROS generation\nof red-emissive AIEgen, and it highlights the importance of minimizing\nthe ROS generation of the fluorescent probes, particularly in the\napplication of long-term imaging of CNS cells.