Methods of preparing particles using a sonication device are disclosed. The methods include directing a particle forming solution containing a particle forming liquid and a particle forming agent as a stream into contact with a sonicating tip of a sonication device under conditions sufficient to transform the stream containing the particle forming solution into a plurality of droplets having a substantially uniform size. The plurality of droplets are contacted with a hardening solution under conditions sufficient to solidify the droplets into particles having a substantially uniform particle size which are then recovered. Particles made in accordance with the methods can be solid or semi-solid and range in size from sub-micron to over 100 microns in diameter.