(483a) Freezing Vortex Rings into Shaped Particles

A miscible drop falling into a quiescent liquid bath forms a vortex-ring-like shape which evolves before eventually dissipating. This talk reports on controlling a crosslinking reaction that occurs upon contact of the drop with the buffer bath to â??freezeâ?? the vortical formations into particles. Remarkably, the gelation reaction can be controlled with precision to yield a range of differently-shaped particles. The particles can be mass produced by an electrospray technique and are attractive for a number of applications, including cell-encapsulation and cell-free protein production. Reaction and mixing timescales compete during particle formation. A phase diagram is reported that shows how to tune this competition to obtain particles of a desired shape.