  Transport properties of particles in confining geometries show very specific
characteristics as lateral drift, oscillatory movement between lateral walls or
the deformation of flexible fibers. These dynamics result from viscous friction
with transversal and lateral channel walls inducing strong flow perturbations
around the particles that act like moving obstacles. In this paper, we modify
the fiber shape by adding an additional, small fiber arm, which leads to T and
L shaped fibers with only one or, respectively, zero symmetry axes and
investigate the transport properties. For this purpose, we combine precise
microfluidic experiments and numerical simulations based on modified Brinkman
equations. Even for small shape perturbations, the transport dynamics change
fundamentally and formerly stable configurations become unstable, leading to
non-monotonous fiber rotation and lateral drift. Our results show that the
fundamental transport dynamics change with respect to the level of fiber
symmetry, which thus enables a precise control of particle trajectories and
which can further be used for targeted delivery, particle sorting or capture
inside microchannels.
