A Digitally Controllable Polymer-Based Microfluidic Mixing Module Array

Raymond H W Lam,Wen J Li

doi:10.3390/mi3020279

Abstract

This paper presents an integrated digitally controllable microfluidic system for continuous solution supply with a real-time concentration control. This system contains multiple independently operating mixing modules, each integrated with two vortex micropumps, two Tesla valves and a micromixer. The interior surface of the system is made of biocompatible materials using a polymer micro-fabrication process and thus its operation can be applied to chemicals and bio-reagents. In each module, pumping of fluid is achieved by the vortex micropump working with the rotation of a micro-impeller. The downstream fluid mixing is based on mechanical vibrations driven by a lead zirconate titanate ceramic diaphragm actuator located below the mixing chamber. We have conducted experiments to prove that the addition of the micro-pillar structures to the mixing chamber further improves the mixing performance. We also developed a computer-controlled automated driver system to control the real-time fluid mixing and concentration regulation with the mixing module array. This research demonstrates the integration of digitally controllable polymer-based microfluidic modules as a fully functional system, which has great potential in the automation of many bio-fluid handling processes in bio-related applications.

Highlights

Research on microfluidics has been advancing rapidly in the past two decades—progressing from single channel devices [1] to complicated and multifunctional systems integrating manifold microfluidic components [2,3,4]
Integrated microfluidic systems, which are composed of multiple microfluidic components, have been typically applied to manipulate, regenerate and sense chemicals and bio-fluids with volumes ranging from micro-liters down to pico-liters [15,16,17,18,19] for delicate and sensitive biochemical applications, e.g., single-cell [20], subcellular [21] and single-molecule [22] analyses
We developed a handheld automated driver system with both specialized hardware and software to control the integrated microfluidic device. (The system design and structure are available in the Appendix.)

Summary

Introduction

Research on microfluidics has been advancing rapidly in the past two decades—progressing from single channel devices [1] to complicated and multifunctional systems integrating manifold microfluidic components [2,3,4]. With the advancement of polymer-based microfabrication technology [5], contemporary microfluidics is no longer restricted to silicon-based devices and can be biocompatible. Integrated microfluidic systems, which are composed of multiple microfluidic components, have been typically applied to manipulate, regenerate and sense chemicals and bio-fluids with volumes ranging from micro-liters down to pico-liters [15,16,17,18,19] for delicate and sensitive biochemical applications, e.g., single-cell [20], subcellular [21] and single-molecule [22] analyses. The current liquid preparation processes often rely on manual pipetting with a low yield and consistency, or on bulky macro-scale automated machines incompatible with the integrated microfluidic systems. These limitations have been critical challenges for practical biomedical and clinical implementations. Portable and digitally controllable micro-machines with precise concentration controls should be developed as the interface between the stock biochemical solutions and the automated microfluidic processes

Methods

Results

Conclusion