On-chip peristaltic pump for pulse-free and accurate liquid delivery in microfluidics

Abstract

Peristaltic pumps are widely used for continuous liquid delivery across various applications. However, their inherent pulsatile flow leads to significant fluctuations, especially in microfluidic systems. In this work, we present an on-chip peristaltic pump for continuous, pulse-free, and precise liquid delivery in microfluidics. The pump utilizes a stepper motor driving three rolling bearings to propel liquid to a microfluidic carrier chip. To mitigate flow pulsation, two air chambers are integrated into the chip as flow stabilizers. The pump achieves stable and accurate flowrates ranging from a few microliters to several hundred microliters per minute, with motor speeds of 10–250 rpm. The average flow rates and total flow volume exhibit a strong linear relationship with motor speed, with a coefficient of determination (R²) close to 1. Notably, the instantaneous flow variation is reduced within 3 % with air chambers, while the pump without the air chambers produces significantly high flow variation (∼ 25.5 %). To demonstrate its applicability, the on-chip pump is employed for sample and sheath flow control in an inertial microfluidic chip, enabling efficient separation of 15 μm and 6 μm particles. These results highlight the pump’s stability, precision, and suitability for feasible applications in microfluidics.