The small length scale associated with microfluidics make these devices uniquely suited for a range of studies, including mixing in low Reynolds number-high Peclet number flows, the stability of high Elasticity number flows, the dynamics of individual microscale objects, and migration of particles and vesicles in suspensions. In this talk, I will briefly review recent developments in rapid prototyping methods and describe our recent work using microfluidic stagnation point flows and on migration in suspensions. Microfluidic stagnation point flows, including cross-slot devices and microfluidic four roll mills, have been designed to trap, manipulate, and analyze genomic DNA, particles, drops, capsules, and vesicles. Using these devices, we have demonstrated DNA target sequence detection, site-specific single molecule kinetic analysis of DNA-enzyme interactions, and measurements of the kinetics of polymer-salt induced DNA compaction. More recently, we have extended these studies to single capsules and vesicles, where our interests include measuring membrane properties through controlled deformations, and studies of migration in channel flows of suspensions of particles of controlled size, deformability, and shape.