An integratible acoustic micropump based on the resonance of on-substrate sharp-edge micropillar arrays.

There is a growing demand for reliable, efficient, and easily integrated micropumps for microfluidics. Despite the demonstrated potential of acoustic wave-driven devices for on-chip pumping, current prototypes lack the practicality and integratability for deployment in microfluidic systems. This study presents an acoustic micropump based on the resonance of arrays of on-substrate sharp-edge micropillars prepared in a fluid-filled channel and driven by a piston ultrasonic transducer. At an operating frequency of 80.5 kHz and a driving voltage of 54 V_p-p, a flow rate of 16.2 μL min^-1 is achieved in a downstream straight channel with dimensions 12(L) × 0.6(W) × 0.2(H) mm³. The corresponding pumping pressure exceeds 1.3 kPa, more than an order of magnitude higher than its predecessors. In experimental demonstrations, two micropumps are employed as feeding units for an acoustofluidic particle separation device based on tilted-angle standing surface acoustic waves (TaSSAWs). The current micropump exhibits advantages of high pumping pressure, fast response time, and high reliability, making it a promising pumping unit for lab-on-a-chip systems.