On Multicell-Interaction Chip: In Situ Observing the Interactions between the Astrocytes with Lysosomal Dysfunction and BBB Cells

Lysosomes in astrocytes play vital roles in toxic protein degradation in the brain. Lysosomal dysfunction can lead to abnormal protein deposits, which further induce damage to neurons and the blood-brain barrier (BBB), and thereby affect the interaction between the nervous and vascular systems. Therefore, investigating the interactions between astrocytes with lysosomal dysfunction and BBB cells is of significant importance. However, the lack of effective in vitro models hinders the study of this complex system. Herein, an 8-well arrayed microfence multicell interculture chip (AMMIC) with a hydrophilically optimized surface is introduced for investigating the interactions between astrocytes and BBB cells. Then, a novel lysosome-targeted photosensitizer, IVQ-2Br, is synthesized for inducing controllable oxidative stress damage in the lysosomes of astrocytes. By the combination of the 8-well AMMIC and IVQ-2Br, a model for studying the interactions between astrocytes with lysosomal dysfunction and BBB cells has been constructed. Particularly, severe secondary injuries to BBB cells brought about by oxidative stress, including alterations in cell morphology and activity as well as notable DNA damage, are in situ observed on the 8-well AMMIC. The mediators involved in this oxidative stress injury-mediated intercellular communication are validated to be reactive oxygen species (ROS) and exosomes. This work not only presents an in vitro modeling method for studying cell-cell interactions but also demonstrates the potential of in vitro models constructed through the integration of complex microfluidic chip techniques and photosensitizers for advancing biomedical research.