Photoactuated Micropumps Enable Oscillatory Fluidics and Autonomous Locomotion.

Oscillatory fluid flows underpin transport, mixing, and signal propagation in living systems, yet artificial microfluidic platforms rely almost extensively on external power or chemically driven gradients to reproduce such dynamics. Here, we introduce a fuel-free strategy based on photo-mechanical transduction, in which light is directly converted into mechanical deformation of soft matter to generate reversible and oscillatory fluid flow without gradients. We demonstrated that azobenzene-doped liquid crystal films convert photochemical isomerization into amplified contractile-expansive motion, producing directional and oscillatory flows without chemical fuels, ionic gradients or waste generation. Temporal modulation of light enables programmable flow oscillation that accelerates enzyme kinetics under confinement. Remarkably, the same photo-mechanical mechanism extends seamlessly from microfluidic channels to macroscopic floater at the air-water interface, giving rise to autonomous motion with tunable trajectories. Our findings establish photo-mechanical soft matter as a general platform for gradient-free oscillatory flow and autonomous motion, opening a new direction for lab-on-a-chip technologies, bio-inspired transport, and light driven soft-robotics.