Plasmon-Enhanced Multiplexed Analysis 
of Single Extracellular Vesicles for Molecular Cancer Diagnosis

Exosomes, more broadly extracellular vesicles (EVs), represent new opportunities for cancer screening, diagnosis, and longitudinal treatment monitoring. Current EV analyses encounter technical challenges since sensitivities are often limited to bulk analyses. EVs in clinical samples are inherently heterogeneous, with various cellular origins and subtypes that differ in size and molecular composition. It is thus critical to develop a novel EV sensing technology that enables single EV analysis. We have designed plasmonic nanostructures that exhibit strong resonances and thus significantly amplify EVs’ weak optical signals. The nanoplasmonic sensor chips were fabricated on a wafer scale for low-cost, high-throughput chip production. We demonstrated robust signal enhancements in multiple fluorescence channels. This allows us to quantify tumor-derived EVs as well as cancer-associated proteins and RNAs at a single EV level for cancer detection and monitoring. Using the single EV sensing platform, we demonstrated the sensitive detection of ovarian cancer and cholangiocarcinoma from EV analysis in human clinical samples and the potential of EV analysis to evaluate and predict patients' responses to chemotherapy in breast cancer. The simple, robust, and sensitive multiplexed single EV assay could improve our understanding of EV biology and accelerate clinical translation for various diseases.