On Multicell-Interaction\nChip: In Situ Observing the\nInteractions between the Astrocytes with Lysosomal Dysfunction and\nBBB Cells

Lysosomes in astrocytes play vital roles in toxic protein\ndegradation\nin the brain. Lysosomal dysfunction can lead to abnormal protein deposits,\nwhich further induce damage to neurons and the blood–brain\nbarrier (BBB), and thereby affect the interaction between the nervous\nand vascular systems. Therefore, investigating the interactions between\nastrocytes with lysosomal dysfunction and BBB cells is of significant\nimportance. However, the lack of effective in vitro models hinders\nthe study of this complex system. Herein, an 8-well arrayed microfence\nmulticell interculture chip (AMMIC) with a hydrophilically optimized\nsurface is introduced for investigating the interactions between astrocytes\nand BBB cells. Then, a novel lysosome-targeted photosensitizer, IVQ-2Br,\nis synthesized for inducing controllable oxidative stress damage in\nthe lysosomes of astrocytes. By the combination of the 8-well AMMIC\nand IVQ-2Br, a model for studying the interactions between astrocytes\nwith lysosomal dysfunction and BBB cells has been constructed. Particularly,\nsevere secondary injuries to BBB cells brought about by oxidative\nstress, including alterations in cell morphology and activity as well\nas notable DNA damage, are in situ observed on the 8-well AMMIC. The\nmediators involved in this oxidative stress injury-mediated intercellular\ncommunication are validated to be reactive oxygen species (ROS) and\nexosomes. This work not only presents an in vitro modeling method\nfor studying cell–cell interactions but also demonstrates the\npotential of in vitro models constructed through the integration of\ncomplex microfluidic chip techniques and photosensitizers for advancing\nbiomedical research.