Tools for Single Molecule Imaging

The brightness and photostability of quantum dot materials have made them attractive fluorescent labels for single molecule imaging, yet the size and ease of conjugation to biological targets are still practical challenges for most experiments. We are developing novel genetically encoded proteins, called fluorogen activating peptides (FAPs) that bind and activate quenched light-harvesting polymer materials made from multiple chromophores (fluorogenic dyedrons). This technology allows bright, stoichiometric labeling using a genetically fused expression tag, and can be applied to both purified protein labeling for biophysical measurements and to measurements in living cells.

The noncovalent nature of the FAP-fluorogen system gives rise to interesting photostability properties that can potentially be exploited in single molecule imaging. We are investigating and optimizing the photostability of FAP-fluorogen complexes with the goal of producing compact, bright, photstable genetically encoded tagging strategies as an alternative to quantum dot labeling.