A power-free, parallel loading microfluidic reactor array for biochemical screening

Yanwu Liu,Gang Li

doi:10.1038/s41598-018-31720-y

Abstract

This paper presents a power-free, self-contained microfluidic device in which a number of nanoliter-sized droplets can be parallelly and accurately metered and mixed for high-throughput analysis and/or portable systems. In this system, the absorption of air by pre-degassed PDMS and the change of capillary force due to sudden narrowing of the channel cross-section provide the mechanism for actuating, metering and mixing the flow of fluid in the microfluidic channels and chambers. With an array of channels and capillary valves combined with an array of pre-degassed PDMS pump chambers, the device can perform multiple liquid dispensing and mixing in parallel, and its performance and reproducibility are also evaluated. As a practical application, the proposed device is used to screen crystallization conditions of lysozyme. This device needs neither external power nor complex instruments for fluid handling. Thus, it offers an easy-to-use, inexpensive and power-free way to perform multiple nanoliter-volume distinct reactions in parallel format and should be ideally suitable for individual laboratories for various applications such as enzyme assay, protein crystallization, drug discovery, and combinatorial chemistry.

Highlights

As the fields of combinatorial chemistry and high-throughput screening (HTS) have been growing, it has become increasingly desirable to develop the capabilities of rapidly and reliably carrying out chemical and biochemical reactions in large numbers using small quantities of samples and reagents[1]
It consists of three major components: an array of glass capillary tubes, a microfluidic chip and a place and play” (PnP) PDMS pump
Unlike our previous work, where the PnP PDMS pump slab contains 3 independent chambers and can only achieve a pair of liquid plugs metering and mixing, the modular PnP PDMS pump matching with the microfluidic reactor array (MRA) chip is made of a PDMS slab with 25 independent chambers, which can drive 25 isolated flows and achieve 24 pair of liquid plugs metering and mixing in parallel

Summary

Introduction

As the fields of combinatorial chemistry and high-throughput screening (HTS) have been growing, it has become increasingly desirable to develop the capabilities of rapidly and reliably carrying out chemical and biochemical reactions in large numbers using small quantities of samples and reagents[1]. To avoid costly and non-disposable integrated control components, a number of simple liquid-handling techniques without external power requirements have been developed, such as surface tension-based passive pumping[14,15], evaporation-based passive pumping[16,17,18], capillary flow[19,20,21], gravity-driven flow[22,23], and finger-actuated pumping[24,25,26] These portable liquid-handling techniques address some important challenges in the design of microfluidic devices for disposable applications, such as www.nature.com/scientificreports/. By combining natural capillary action and the PnP PDMS pump, we develop a power-free and self-contained microfluidic reactor array (MRA), which autonomously and parallelly performs fluid loading, metering and mixing without external power or complex instruments

Methods

Results

Conclusion