Digital Lasing Biochip for Tumor-Derived Exosome Analysis.

Digital microfluidics represents an emerging versatile platform that offers numerous advantages in biomolecule detection. However, conventional probes often lack high-intensity and high-sensitivity signals, making it challenging for precise and automatic analysis. Recently, optical microresonators stand as a prominent high-sensitivity detection in the biological field. Here we introduce whispering gallery mode (WGM) microlasers into the microwell array, forming a digital lasing detection system. The lasing signal makes it highly sensitive, which amplifies the subtle changes via the strong interactions of light and matter. The microfluidic droplet technique further allowed microlasers with uniform laser thresholds and high-throughput fabrication. We utilized this tool for the analysis of exosomes derived from tumor spheroids. We believe that this digital optofluidic system could serve as a promising tool in diverse biomolecule assays and various biomedical applications.