  Microfluidics involves the manipulation of flows at the microscale, typically
requiring external power sources to generate pressure gradients. Alternatively,
harnessing flows from active fluids, which are usually chaotic, has been
proposed as a paradigm for the development of micro-machines. Here, by
combining experimental realizations and simulations, we demonstrate that the
addition of triangular-shaped inclusions into an active nematic gel can locally
break the fore-aft symmetry of active turbulence and stabilize flow fields with
self-pumping capabilities. The proposed strategy has enabled us to generate
wall-free and self-powered microfluidic systems capable of both cargo transport
and mixing along with the downstream flow. We analyze the performance of these
active pumps, both isolated and within cooperative ensembles in terms of their
output velocity and hydrostatic pressure buildup. Finally, we demonstrate
strategies to incorporate them into specifically designed microfluidic
platforms to advantageously tailor the geometry of active flows. Our results
reveal new possibilities for leveraging the self-organized mechanodynamics of
active fluids.
