Random Metastructures for Nanoscale Visualization of Single-Exosome Dynamics in a Gut-Brain-Axis-on-a-Chip.

This study introduces an innovative nanophotonic biosensor system designed to explore exosome dynamics within the gut-brain axis, highlighting the bidirectional and biochemical communication between the gastrointestinal tract and the central nervous system. The proposed system incorporates coculture environments for various cell types, microfluidic control of exosomes, and super-resolution imaging capabilities for both exosomes and live cells. While enabling real-time observation of long-range exosome dynamics within the gut-brain-axis-on-a-chip, this approach offers superior spatial resolution for visualizing individual exosomes in both donor and recipient cells. Through precise microfluidic manipulation, exosomes are observed as they are secreted from donor cells, transported within the chip, and interact with recipient cells in a coculture environment, mimicking the communication process occurring in the gut-brain axis. The dynamics of exosome transport within the gut-brain axis model are expected to improve the understanding of their biological functions and potential applications.