A reliable and programmable acoustofluidic pump powered by oscillating sharp-edge structures

Abstract

We present a programmable acoustofluidic pump that utilizes the acoustic streaming effects generated by the oscillation of tilted sharp-edge structures. This sharp-edge-based acoustofluidic pump is capable of generating stable flow rates as high as 8 μL min(-1) (~76 Pa of pumping pressure), and it can tune flow rates across a wide range (nanoliters to microliters per minute). Along with its ability to reliably produce stable and tunable flow rates, the acoustofluidic pump is easy to operate and requires minimum hardware, showing great potential for a variety of applications.

Figures

Fig. 1

(a) Schematic of the sharp-edge-based acoustofluidic pumping device. This device includes a PDMS microfluidic channel and a piezoelectric transducer. (b) Schematic showing the acoustic streaming phenomenon around the tip of a tilted, oscillating sharp-edge structure. (c) Schematic showing the design of the channel and sharp-edge structure.

Fig. 2

(a) Characterization of the acoustic streaming patterns developed around the tips of the 30° tilted sharp-edge structures. (b) Simulated results showing the streaming velocity in our pump in the presence of an acoustic field: a net flow of fluid from left to right is generated.

Fig. 3

Experimental images showing the pumping behavior by indicating the movement of polystyrene beads at different time frames when (a) t0 = 0 s, (b) t1 = 1 s, (c) t2 = 2 s, and (d) t3 = 3 s. (Red, yellow, and blue circles indicate three representative groups of beads.)

Fig. 4

Experimental results illustrating the controllability and tunability of our acoustofluidic pump. (a) Comparison of generated pumping flow rates with various tilting angles of sharp-edge structures as a function of the voltages applied to the piezoelectric transducer. The 30° tilted sharp-edge structures could generate a flow rate as high as 8 μl/min under 50 VPP. (b) Characterization of flow rate profiles when alternately switching the piezoelectric transducer ON and OFF with different burst frequencies: (Black) burst frequency of 2 Hz, and (Red) burst frequency of 0.5 Hz.