Microfluidic Passive Valve Regulator for Controlling Flow Rates

In microfluidic applications where cost effectiveness and miniaturization are key, the use of passive microvalve offers significant benefits. This study introduces an innovative passive microfluidic valve design comprising a fluid chamber, a flexible membrane, and a rectangular control chamber, enabling effective flow rate management at exceptionally pressures. The model was created using the 3D photolithography method, and the passive microvalve was evaluated under pressure circumstances that are both constant and time-dependent. In the experiment, the microfluidic passive valve demonstrated a constant flow rate when the pressure ranged from 40 kPa to 70 kPa. This regulator can achieve a consistent delivery flow rate of up to 53 ± 2.5µL/min with deviations under 4.5%, as demonstrated by the testing outcomes. Furthermore, the microfluidic passive valve has demonstrated the capability to maintain a stable liquid flow rate under fluctuating conditions, specifically under square wave pressure variations over time. The suggested microfluidic passive valve device may be used in portable, low-cost Lab-on-a-Chip (LoC) applications to precisely control flow. We anticipate this innovative passive microfluidic valve will work well for regulating fluid flow in systems with broader applications or portable microfluidic devices.