Lectin-enabled glycan signature of small extracellular vesicles by surface-enhanced Raman spectroscopy

Glycans are essential membrane components that play critical roles in various biological processes, and their aberrant expression is often associated with diseases such as cancer. Lectins are carbohydrate binding proteins capable of binding specific glycan structures and have been widely used to study glycosylation patterns on cell membranes. However, multiplex glycan profiling of cancer-derived small extracellular vesicles (sEVs) using lectins remains limited due to their high heterogeneity, the small surface area of individual vesicles, the low abundance of specific glycan motifs, and the lack of robust multiplexing platforms. In this study, we developed a lectin-based surface enhanced Raman spectroscopy (SERS) assay for both individual glycan structure detection and simultaneous multiplex profiling of glycans on the surface of cancer cell-derived sEVs in a single test. We evaluated the sensitivity and specificity of this platform and validated its accuracy through a proof-of-concept study by detecting changes in the surface glycan profile of sEVs following glycosidase treatment. Using four different lectin-based SERS nanotags, we performed multiplex glycan profiling and observed distinct changes in glycan signatures after glycosidase treatment. These findings highlight the strong potential of this assay for multiplex sEV glycan profiling in a single sample with a single test, indicating its potential for future clinical applications, particularly in cancer diagnosis.