Microlasers Integrated with Microfluidic Droplets for Exosome Profiling at the Single-Cell Level

Single-cell exosome analysis is critical for elucidating the cellular heterogeneity and intercellular communication. However, conventional analytical tools often exhibit limited sensitivity and are prone to interference by complex biological fluids. In this study, we present whispering-gallery-mode (WGM) microlasers as a platform for the highly sensitive analysis of exosomes at the single-cell level. These microlasers can be coencapsulated with individual cells in microfluidic droplets, enabling real-time and long-term monitoring of exosome secretion. By integrating fluorescence resonance energy transfer (FRET) mechanisms with the laser emission, subtle interactions between exosomes and the resonant light are amplified, thereby achieving ultrahigh detection sensitivity. The droplet microfluidics allows for the high-throughput generation of microlasers with uniform optical properties and consistent performance. This approach offers a powerful tool for advanced biomolecular assays and holds significant promise for a wide range of biomedical applications, including diagnostics, therapeutics, and cellular profiling.