Anomalous kinetics of depletion zone growth with one-dimensional geometry: Photobleaching experiments and simulations

We studied the kinetics of a diffusion-limited trapping reaction A + T → T in an effective one-dimensional geometry by experiments, supported by simulation calculations. The experiments are based on the photobleaching reaction of fluorescein dyes. The main parameter of interest is the θ-distance, which is related to the expansion of the depletion zone and can be measured directly from experiment. We found that θ-distance scales with t^1/2 asymptotically, as predicted by previous theory. In addition, we found that the θ-distance increases faster than t ^1/2 inside the trap at early times, which has not been explored previously. Furthermore, there is a third, intermediate regime, with a slow increase of slope. Our experimental results are consistent with our simulation results.