High-resolution optical imaging from trajectory time distributions.

Trajectory time distribution optical microscopy (TTDOM), which records the mean off-times of single molecular fluorescent indicators that light up when they collide with vesicles, is extended to record fluorescence durations or on-times. TTDOM can distinguish shapes of objects that are smaller than the diffraction limited resolution. The fluorescence duration time image can also provide high-resolution information. The effects of the threshold that separates fluorescent bursts from background signals and of two or more probes visiting the vesicles simultaneously have been investigated systematically. New experimental results along with simulations indicate that TTDOM is capable of providing the size and shape of objects and information on probe-vesicle binding.