A trap-and-release integrated microfluidic system for dynamic microarray applications.

Dynamic microarrays hold great promise for advancing research in proteomics, diagnostics and drug discovery. However, this potential has yet to be fully realized due to the lack of reliable multifunctional platforms to transport and immobilize particles, infuse reagents, observe the reaction, and retrieve selected particles. We achieved all these functions in a single integrated device through the combination of hydrodynamic and optical approaches. Hydrodynamic forces allow simultaneous transportation and immobilization of large number of particles, whereas optical-based microbubble technique for bead retrieval gives dexterity in handling individual particles without complicated circuitry. Based on the criterion derived in this paper, the device was designed, and fabricated using standard photolithography and soft lithography methods. We examined the dynamics of bubble formation and dissipation in the device, and parametric studies revealed that higher power settings at short intervals were more efficient than low power settings at longer intervals for bead retrieval. We also demonstrated the capabilities of our device and its potential as a tool for screening methods such as the "one-bead-one-compound" (OBOC) combinatorial library method. Although both approaches, hydrodynamic confinement and optical-based microbubbles, are presented in one device, they can also be separately used for other applications in microchip devices.