Frequency-specific, valveless flow control in insect-mimetic microfluidic devices

TL;DR

This paper presents insect-inspired microfluidic devices that control flow using frequency-dependent actuation, eliminating the need for internal valves and enabling portable, low-cost lab-on-a-chip applications.

Contribution

It introduces a novel valveless, frequency-specific flow control mechanism inspired by insect respiratory systems in microfluidic devices.

Findings

Flow rate and direction controlled solely by actuation frequency

Multichannel chips respond selectively to global frequency signals

Insect-mimetic designs reduce actuation complexity

Abstract

Inexpensive, portable lab-on-a-chip devices would revolutionize fields like environmental monitoring and global health, but current microfluidic chips are tethered to extensive off-chip hardware. Insects, however, are self-contained and expertly manipulate fluids at the microscale using largely unexplored methods. We fabricated a series of microfluidic devices that mimic key features of insect respiratory kinematics observed by synchrotron-radiation imaging, including the collapse of portions of multiple respiratory tracts in response to a single fluctuating pressure signal. In one single-channel device, the flow rate and direction could be controlled by the actuation frequency alone, without the use of internal valves. Additionally, we fabricated multichannel chips whose individual channels responded selectively (on with a variable, frequency-dependent flow rate, or off) to a single, global actuation frequency. Our results demonstrate that insect-mimetic designs have the potential to drastically reduce the actuation overhead for microfluidic chips, and that insect respiratory systems may share features with impedance-mismatch pumps.