Microfluidic-based single micro-particle/cell handling techniques

• Trap-and-release of a single micro-particle/cell using dual-function elastomeric valves
• Dynamic single microbead array for multiplex bead-based assay
• Dynamic single cell array for quantitative single-cell analysis (in progress)
• Pairing/clustering/merging of micro-droplets for biochemical applications (in progress)
• Droplet-based microfluidic system integrated with micropump for high-throughput analysis of biomolecular interactions (in progress)

Trap-and-release of a single micro-particle/cell

Microfluidic-based manipulation techniques of single particles such as microbeads, hydrogel particles, and biological cells have been developed because of their potential applications in the fields of biology and chemistry. We developed a simple method for trapping and releasing single particles, such as microbeads and living cells, using dual-function elastomeric valves. Our key technique is the utilization of the elastomeric valve as a dual-function removable trap instead of a fixed trap and a separate component for releasing trapped particles, thereby enabling a simple yet effective trap-and-release of particles. Our simple method can be integrated into microfluidic systems that require single or multiple particle arrays for quantitative and high-throughput assays in applications within the fields of biology and chemistry.

• Full integration of the trap-and-release functions and simple fabrication (i.e., single-layer valve)
• Long-term and real-time particle/cell observation
• Collection of a controllable number of particles/cells
• Multiple particles/cells trapping (for heterotypic cell-cell interaction study and cell fusion)

Dynamic single microbead array for multiplex bead-based assay

A simple yet effective dynamic bead-based microarray is necessary for multiplexed high-throughput screening applications in the fields of biology and chemistry. We developed 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). A sequential microbead release technique via a multi-step ‘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.