(300a) Stokes Trap: Multiplexed Particle Trapping and Manipulation Using Fluidics

The ability to trap and control single particles in free solution has led to major advances in science and engineering. In this talk, we report the development of the Stokes Trap, which is a multiplexed microfluidic trap for control over an arbitrary number of small particles in a microfluidic device. Our work involves the design and implementation of “smart” flow-based devices by coupling feedback control with microfluidics, thereby enabling new routes for the fluidic-directed assembly of particles. Here, we discuss the development of a new method to achieve multiplexed microfluidic trapping of an arbitrary number of particles using the sole action of fluid flow. In particular, we use a Hele-Shaw microfluidic cell to generate hydrodynamic forces on particles in a viscous-dominated flow defined by the microdevice geometry and imposed peripheral flow rates. Addition of multiple inlets to the cell increases the degrees of freedom for trapping additional particles. We employ a model-predictive controller for the non-linear system and solve a constrained optimal control problem in real-time. This platform allows for a high degree of flow control over individual particles and can be used for fluidic-directed assembly by bringing two particles together in time and space. From a broader perspective, our work provides a solid framework for guiding the design of next-generation, automated on-chip assays.