A microfluidic-based dynamic microarray system with single-layer pneumatic valves for immobilization and selective retrieval of single microbeads

Abstract

A simple yet effective dynamic bead-based microarray is necessary for multiplexed high-throughput screening applications in the fields of biology and chemistry. This paper introduces a microfluidic-based dynamic microbead array system using pneumatically driven elastomeric valves integrated with a microchannel in a single polydimethylsiloxane (PDMS) layer that performs the following functions: single-microbead arraying with loading and trapping efficiencies of 100 %, sequential microbead release for selective retrieval of microbeads of interest, and rapid microarray resettability (< 1 s). The key feature is the utilization of an elastomeric membrane as a valve for trapping and releasing single microbeads; this membrane is deformable depending on the applied pneumatic pressure, thereby simply providing a dual trap-and-release function. We propose an effective single-microbead-trapping mechanism based on a dynamic flow-change network and a mathematical model as the design criterion of a trapping site. A sequential microbead release technique via a multistep "release-retrap-and-repeat" method was developed for the selective retrieval of trapped microbeads with a simple configuration consisting of a single PDMS layer and a simple macro-to-micro connection. The proposed dynamic microbead array could be a powerful tool for high-throughput multiplex bead-based drug screening or disease diagnosis.