  We consider model of a complex particle that consists of a rigid shell and a
nucleus with spatial asymmetric interaction. The particle's dynamics with the
nucleus driven by a periodic excitation is considered. It is shown that
unidirectional self-propulsed particle motion arises in the absence of spatial
and temporary asymmetry of external potentials and influences. Transport modes
are the general case of complex particle dynamics in the presence of nonlinear
friction or periodic external potential. The changes of average transport
velocity and direction of transport are determined by qualitative changes of
internal dynamics regimes: local attractor bifurcations in the internal phase
space of the complex particle. Finally, microbiological relevance of the
proposed model is briefly discussed.
