Molecularly Imprinted Nanozyme Intelligent Array Sensing Platform Realizes the Enrichment and Quantitative Detection of Small Extracellular Vesicles

As tumor-associated biomarkers, proteins on small extracellular vesicles (sEVs) play a critical role in revealing tumor subtypes and disease progression. Nevertheless, the rapid isolation of sEVs and the quantitative detection of their surface proteins remain challenging. In this study, we developed a nanozyme (PB-MIP-PEG) array sensing platform based on molecular imprinting technology (MIT), which can efficiently enrich sEVs and simultaneously detect three proteins: CD20, CD19, and PD-L1. Fe3O4@TiO2 magnetic beads interact with phosphate groups in the sEVs phospholipid bilayer and, under an external magnetic field, achieve effective separation from complex samples. Prussian blue (PB) nanozymes with peroxidase (POD)-like activity, coated with a silicon dioxide (SiO2) imprinting layer, showed enhanced enrichment toward 3,3′,5,5′-tetramethylbenzidine (TMB), which contributed to improved catalytic activity and detection sensitivity. Furthermore, density functional theory (DFT) and molecular dynamics (MD) simulations further revealed that hydrogen bonding and π–π stacking are the dominant interactions during the imprinting process. By integration of colorimetric imaging with a position-encoding system and employing a convolutional neural network-long short-term memory (CNN-LSTM) model for automated feature extraction, the concentrations of CD20, CD19, and PD-L1 were rapidly distinguished. This array sensing platform, which integrates molecularly imprinted nanozymes with neural network models, provides a new approach for the intelligent analysis of sEVs surface proteins and demonstrates a potential application value in lymphoma-related monitoring.