| 초록 |
We report an active aptamer-based imaging probe that specifically switches its fluorescence state upon binding to a targeted cell-surface receptor. The aptamer-conjugated polydiacetylene probe (ACP) is a nanometer-scale polymeric particle designed to be in a “dark” state and emit minimal background fluorescence in an unbound state. However, when it binds to the target receptor, it undergoes a large-scale conformational change in its polymer backbone that dramatically increases the fluorescence of the polydiacetylene, and the probe switches to its “bright” state. As a model, we describe an ACP probe for imaging epithelial cancer cells that overexpress epithelial cell adhesion molecule (EpCAM) on their surface. We show that our ACP probes enable specific visualization of EpCAM-expressing cancer cells by switching their fluorescence emission from nonfluorescence to fluorescence (λem = 563 nm) upon binding to cell-surface EpCAM molecules. We therefore believe that our nanoscale probes offer a powerful strategy for achieving exceptionally sensitive, low-background imaging of cells and tissues. Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (KRF-2012-R1A1A3015259). |
