According to the YouTube description for this video:
Researchers at NC State have developed a way to print liquid metals into 3D structures at room temperature. The structures are stabilized by a thin oxide 'skin' that forms on the liquid metal. The approaches shown here represent new ways to direct write metals in 3D. In addition, the resulting components can, in principle, self-heal
The paper, "3D Printing of Free Standing Liquid Metal Microstructures," can be found here.