Carbon nanosphere-based fluorescence aptasensor for targeted detection of breast cancer cell MCF-7

In this work, carbon nanosphere (CNS)-based fluorescence “turn off/on” aptasensor was developed for targeted detection of breast cancer cell MCF-7 by conjugation with FAM (a dye)-labeled mucin1 (MUC1) aptamer P0 (P0-FAM), which can recognize MUC1 protein overexpressed on the surface of MCF-7. Different from other carbon based fluorescence quenching materials, CNSs prepared by the carbonization of glucose not only have the high fluorescence quenching efficiency (98.8%), but also possess negligible cytotoxicity (in the concentration range of 0–1 mg/mL, which is 10 times higher than that of traditional carbon nanotubes or graphene oxide (0–100 µg/mL)). As for the detection of the mimic of the tumor antigen MUC1, the resulting fluorescence intensity increases nearly linearly in the range of 0–6 μM with the limit of detection (LOD) of 25 nM.