Creating a fluorescent “AND” logic gate aptamer platform for identifying exosomes derived from breast cancer subtypes

Breast cancer is a globally prevalent malignancy, and early classification of breast cancer is beneficial for formulating accurate treatment plans and improving prognosis. In this work, we engineered an innovative dual-marker approach, capitalizing on the precision of “AND” logic gates, to precisely identify different subtypes of exosomes derived from breast cancer. We designed two distinct nucleic acid aptamers:PD-L1 (Programmed cell death-ligand 1) aptamer conjugated with Cy3, and EpCAM (Epithelial cell adhesion molecule) aptamer labeled with Cy5. The conjugation of both aptamers and specific connectors culminated in the establishment of a robust detection system. Upon successful binding to breast cancer-derived exosomes, a remarkable Förster Resonance Energy Transfer (FRET) phenomenon transpires, enabling the detection of the target exosomes. Through the optimization of the linker, we extended the application of this method to fluorescence imaging, which is capable of elucidating the interactions between exosomes and immune cells. This not only visualizes the process of exosome internalization into receptor cells but also paves the way for a novel non-invasive diagnostic strategy for breast cancer.