  Artificially synthesized Janus particles have tremendous prospective as
in-vivo drug-delivery agents due to the possibility of self-propulsion by
external stimuli. Here we report the first ever computational study of
translational and rotational motion of self-propelled Janus tracers in a het-
erogeneous polymeric environment. The presence of polymers makes the
translational mean square displacement (MSD) of the Janus tracer to grow very
slowly as compared to that of a free Janus tracer, but surprisingly the mean
square angular displacement (MSAD) is significantly increased as observed in a
recent experiment. Moreover, with the increasing propulsion velocity, MSAD
grows even faster. However, when the repulsive polymers are replaced with
polymers with sticky zones, MSD and MSAD both show sharp decline.
