Single-molecule Detection of Ultrafast Biomolecular Dynamics with Nanophotonics

Proteins can feature ultrafast structural dynamics in the nanosecond timescale which are very challenging to measure using conventional techniques such as single-molecule Förster resonance energy transfer (smFRET). So far, the limited fluorescence brightness and the relatively long fluorescence lifetimes have limited the temporal resolution of smFRET to the 10 ns range. Moreover, these ultrafast smFRET measurements require very long acquisition times, often above several hours.

In a recent JACS publication in collaboration with the teams of Ben Shuler and Robert Best, the nanophotonic fluorescence enhancement in zero-mode waveguides is used to push forward the smFRET measurements of ultrafast protein dynamics in the low nanosecond range. The previously inaccessible dynamics of a short intrinsically disordered peptide were probed with nanosecond FCS and smFRET, paving the way to the investigation of very rapid biomolecular dynamics.

Significance:

-    The acquisition time needed for nanosecond FCS is reduced by more than one order of magnitude. Measurements that were taking several hours can now be performed in 20 minutes.

-    The experimental data can be compared with all-atom molecular dynamics simulations, and used to further improve the accuracy of the numerical model. 

-    ZMWs from our group can be easily implemented in other labs with consistent optical performance.