It uses an ink made of silver nanoparticles, which is hardened with a laser as it exits the extruder. The print bed is rotary, and the nozzle moves along three axes, which results in the ability to create swooping curved forms made of silver wire less than the width of a human hair in just a few seconds. These wires are also highly conductive. You can find the full paper in the early edition of PNAS, published today.