Recent Advances in Plasmonic Sensing Techniques for Exosome Detection and Composition Analysis

Abstract Exosomes are extracellular vesicles with sizes typically ranging from 30 to 200 nm. They carry a wealth of molecular information from their parental cells and are abundant and stable in biofluids. Due to their outstanding characteristics, exosomes have emerged as a promising biomarker for disease diagnostics over these years. Among the analytical techniques, surface plasmon resonance (SPR) method turns out to be a promising tool in exosome detection due to its merits of label‐free, highly sensitive and real‐time sensing capabilities. In this review, a comprehensive summary of various plasmonic sensing techniques, focusing on both propagating SPR (PSPR) and localized SPR (LSPR) platforms, demonstrating their characteristics, sensing performances, and practical applications is presented. Furthermore, the fundamental working principles underlying current surface functionalization methods for plasmonic substrates are introduced, providing guidance for selecting the appropriate methods for specific exosome capture and detection. Recent advancements in enhancing sensing performance for exosome detection using PSPR, LSPR, and surface‐enhanced Raman scattering platforms are also surveyed. Moreover, representative clinical applications that leverage these plasmonic sensing techniques are also highlighted. Finally, the current challenges and future research directions in this field are also discussed, offering insights into the potential of exosomes and plasmonic sensing in biomedical research and clinical practice.