A simple and direct reading flow meter fabricated by two-photon polymerization for microfluidic channel

This study introduces an innovative micromachine that enables precise measurement of the flow rate at the micron scale (μl/min) in microfluidic channel. It is fabricated by the state-of-the-art technique of two-photon polymerization and consists of: a rod-spring, a water-drop-shaped frame, and an indicator situated inside a microfluidic channel. The indicator is deflected by the flowing fluid while restrained by the spring to establish an equilibrium indication according to the flow rate. In the practical tests, the flow successfully agitates the spring in a proper deflection. The relationship between the flow rate and the deflection angle was calibrated.