Single quantum dot tracking, one photon at a time

In this talk, I will present our research on single quantum dot (QD) tracking in live cells. QDs are bright fluorescent probes that have advantageous properties to address biological questions at the single-molecule level. Although commercially available and in principle ready for labeling, there is some advantages of going through the full route of synthesis, solubilization and functionalization. As an illustration, I will discuss a universal approach we recently proposed to target membrane proteins that can potentially be extended to cytoplasmic ones. Results obtained with this system as well as others will be discussed, leading to a presentation of new analytical tools we have proposed to analyze long QD trajectories. I will briefly present our results regarding the long standing “raft” hypothesis obtained with this approach. Finally, I will talk about a new detector we have been developing in collaboration with astrophysicists in Berkeley that allows us to track QDs one photon at a time, providing a wealth of information not accessible using cameras.