Thermophoretic trapping and manipulation of single molecules

We demonstrate the long time trapping of single DNA molecules in liquids by feedback driven dynamic temperature fields. By spatially and temporally varying the temperature at a plasmonic nanostructure, thermophoretic drifts are induced that are used to trap single nano-objects. A feedback controlled switching of local temperature fields allows us to confine the motion of a single DNA molecule for minutes. The DNA conformation and conformation dynamics are analyzed in terms of a principle component analysis. Current results are in agreement with previous measurements in thermal equilibrium and suggest only a weak influence of the inhomogeneous temperature rise on the structure and dynamics in the trap.