Sensitive fluorescent sensor for the fuzzy exosomes in serum based on the exosome imprinted polymer sandwiched with aggregation induced emission

Cancer cell derived exosomes are considered as one of the potential biomarkers for the non-invasive cancer diagnosis. Nevertheless, how to efficiently and sensitively detect exosomes is still the biggest obstacle. The not yet well-understood surface of exosomes restricts the application of antibodies or epitope imprinting. In addition, the exosomal detection in serum was challenging. Encouragingly, utilizing the self-assembly property of imprinted polymer technology, little-known intact exosomes was directly used as template here to tail the formation of exosome-binding 3D cavities on the surface of the magnetic particles. Analytes in serum were thus selectively captured by this template eluted imprinted polymer. Furthermore, aptamer mediated aggregation induced emission (AIE) was utilized to selectively “turn-on” ignite the captured targets. The performance of the strategy was evaluated using lysozyme and fuzzy exosomes as targets successively. The linear relationships were obtained between the fluorescence and the concentration of these targets in serum respectively. The recovery rate of lysozyme in serum was 107%. The detection limit (LOD) of exosome in serum was 1.3 × 10⁶ particles/mL, lower than the current literature. The discrimination of serum from breast cancer patients and healthy people was also achieved, primarily confirming the reliability of this method. To sum up, a novel “light up” sensor with high sensitivity and selectivity in the real biological fluid was developed by the integration of imprinted polymer (MIP) with heterogenous aptamer mediated AIE signaling. Furthermore, the unique potential of MIPs in unknown target recognition revealed herein provides a bright future in the fuzzy target assay.