Optimization of microfluidic trap-based microsphere arrays

We build a microfluidic trap-based microsphere array device. In the device, we design a novel geometric structure of the trap array and employ the hydrodynamic trapping mechanism to immobilize the microspheres. We develop a comprehensive and robust framework to optimize the values of the geometric parameters to maximize the microsphere arrays' packing density. We also simultaneously optimize multiple criteria, such as efficiently immobilizing a single microsphere in each trap, effectively eliminating fluidic errors such as channel clogging and multiple microspheres in a single trap, minimizing errors in subsequent imaging experiments, and easily recovering targets. Microsphere-trapping experiments have been performed using the optimized device and a device with un-optimized geometric parameters. These experiments demonstrate easy control of the transportation and manipulation of the microspheres in the optimized device. They also show that the optimized device greatly outperforms the un-optimized one.