Design and fabrication of an electromagnetic pump for microfluidic applications

This study presents design and fabrication of an electromagnetic pump for microfluidic applications. The pump comprises four major components, namely a lower glass plate containing a copper microcoil, a middle PMMA plate incorporating a PDMS diaphragm with a surface-mounted magnet, upper PMMA channel plates, and a ball-type check valve located at the channel inlet. When an AC current is passed through the microcoil, an alternating electromagnetic force is established between the coil and the magnet. The resulting bi-directional deflection of the PDMS diaphragm causes the check-valve to open and close; thereby creating a pumping effect. The experimental results show that a coil input current of 0.4 A generates an electromagnetic force of 4,700 dynes and a diaphragm deflection of 108 µm. Given an actuating voltage of 3 V and a driving frequency of 15 Hz, the flow rate is found to be 13.2 mL/min under zero head pressure conditions.

I. Introduction

Rapid advances in micro-electro-mechanical systems (MEMS) techniques over the past few decades have led to the development of many microfluidic devices for use in the chemical, biological and environmental monitoring fields. Typically, these devices are designed to perform specific functions such as sample manipulation, reaction, separation and detection, and so on. Compared to their large-scale counterparts, microfluidic devices have a number of important advantages, including a reduced sample and reagent consumption, a shorter analysis time, and an improved sensitivity. Importantly, two or more of such devices can be integrated on a single chip to construct so-called micro-total-analysis systems capable of performing the complete biochemical assay of solutions. In realizing such systems, (micro)pumps play an essential role in manipulating small, precise volumes of solution and driving them through the various components of the chip.