We're big fans of 3D printing, but while many are using the technology to build everyday objects or even buildings, others are going small — and at speeds never possible before. Researchers at the Vienna University of Technology have demonstrated an improved 3D-printing process that allows them to build sculptures — a race car and a replica of St. Stephen's Cathedral are just two examples — as small as a grain of sand. The researchers use a method called two-photon lithography: movable mirrors direct a focused laser over the resin used in the process. The resin contains elements called monomers, which turn solid when activated by two photons of laser light.

While two-photon lithography isn't new, the speed at which the researchers' process works is. "The printing speed used to be measured in millimeters per second," said University professor Jürgen Stampfl. "Our device can do five meters in one second." Having created the new process, the researchers are now trying to develop new resins that will be compatible with biological tissue, hoping to create nanoscale frameworks that living cells will attach to — potentially laying the foundation for the recreation of complex biological structures.