A Pretreatment-Free, Polymer-Based Platform Prepared by Molecular Imprinting and Post-Imprinting Modifications for Sensing Intact Exosomes.

Exosomes are small (30-100 nm) membrane vesicles that serve as regulatory agents for intercellular communication in cancers. Currently, exosomes are detected by immuno-based assays with appropriate pretreatments like ultracentrifugation and are time consuming (>12 h). We present a novel pretreatment-free fluorescence-based sensing platform for intact exosomes, wherein exchangeable antibodies and fluorescent reporter molecules were aligned inside exosome-binding cavities. Such antibody-containing fluorescent reporter-grafted nanocavities were prepared on a substrate by well-designed molecular imprinting and post-imprinting modifications to introduce antibodies and fluorescent reporter molecules only inside the binding nanocavities, enabling sufficiently high sensitivity to detect intact exosomes without pretreatment. The effectiveness of the system was demonstrated by using it to discriminate between normal exosomes and those originating from prostate cancer and analyze exosomes in tear drops.