CHUN-TI CHANG2018-09-102018-09-10201620411723http://www.scopus.com/inward/record.url?eid=2-s2.0-84982867299&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/396685https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982867299&doi=10.1038%2fncomms12401&partnerID=40&md5=4cb169b3d614cea981bb8257814d7d08A vortex ring is a torus-shaped fluidic vortex. During its formation, the fluid experiences a rich variety of intriguing geometrical intermediates from spherical to toroidal. Here we show that these constantly changing intermediates can be 'frozen' at controlled time points into particles with various unusual and unprecedented shapes. These novel vortex ring-derived particles, are mass-produced by employing a simple and inexpensive electrospraying technique, with their sizes well controlled from hundreds of microns to millimetres. Guided further by theoretical analyses and a laminar multiphase fluid flow simulation, we show that this freezing approach is applicable to a broad range of materials from organic polysaccharides to inorganic nanoparticles. We demonstrate the unique advantages of these vortex ring-derived particles in several applications including cell encapsulation, three-dimensional cell culture, and cell-free protein production. Moreover, compartmentalization and ordered-structures composed of these novel particles are all achieved, creating opportunities to engineer more sophisticated hierarchical materials. © 2016 The Author(s).alginic acid; chitosan; inorganic compound; polysaccharide; silica nanoparticle; sodium chloride; tripolyphosphate; compartmentalization; fluid flow; freezing; hierarchical system; nanoparticle; particle size; protein; shape; vortex; animal cell; Article; cell encapsulation; composite material; controlled study; cross linking; electric conductance; electrospray; fluid flow; freezing; human; human cell; hydrogel; nanofluidics; nonhuman; rat; simulation; surface tension; viscosity; vortex motionjournal article10.1038/ncomms124012-s2.0-84982867299