  We investigate the possibility of arbitrarily high energy in the center of
mass(CM) frame of colliding particles in the vicinity of the infinite red-shift
surface of the spherically symmetric, static charged regular black holes
(Bardeen black hole, Ay\'{o}n-Beato and Garc\'{i}a black hole, and Hayward
black hole). We show that the CM energy of colliding particles near the
infinite red-shift surface of the \emph{extreme} regular black holes are
arbitrarily large while the non-extreme regular black holes have the finite
energy. We also compute the equation of innermost stable circular orbit(ISCO),
marginally bound circular orbit(MBCO) and circular photon orbit(CPO) of the
above regular black holes, which are most relevant to black hole accretion disk
theory.
