MUC1 detection and in situ imaging method based on aptamer conformational switch and hybridization chain reaction

Mucin 1 (MUC1) overexpression in tumor cells is related to various cancers, including breast, stomach, and lung cancer. MUC1 detection and imaging are important for cancer localization in tissue sections to support histopathological diagnosis. In this study, we developed a simple, enzyme-free MUC1 detection and in situ imaging method. Three hairpin probes, Apt-trigger, HP1-FAM, and HP2, were designed for MUC1 recognition and hybridization chain reaction (HCR). The Apt-trigger probe was composed of two sequences: the MUC1 aptamer and HCR trigger sequence. The 5' end of the HP1-FAM probe was modified with a FAM signal molecule. In the presence of MUC1, the aptamer sequence is activated and bound to MUC1, which opens the hairpin structure. Then, the trigger sequence gets exposed and, complementary to HP1-FAM, triggers a continuous HCR process. This method was successfully used to detect MUC1 of 200 pM-25 nM and MUC1 in situ imaging in specific cells, such as human breast carcinoma (MCF-7) and human colon cancer (HT-29) cells.