  The dynamics of a relativistic particle in a Reissner-Nordstrom background is
studied using Caianiello model with maximal acceleration. The behaviour of the
particle, embedded in a new effective geometry, changes with respect to the
classical scenario because of the formation of repulsive potential barriers
near the horizon. Black hole formation by accretion of massive particles is not
therefore a viable process in the model. At the same time, the naked
singularity remains largely unaffected by maximal acceleration corrections.
