Instead of the traditional metalworking technique of heating and shaping the material, Caltech researchers have utilized hydrogel infusion—first creating a structure out of the contact lens-like material and then infusing it with metal precursor ions. After the structure has solidified, the original hydrogel structure is burned away, leaving the metal in place. Using this technique, metal can be printed at a width of 40 microns, less than half the size of a human hair. This breakthrough will allow aerospace and biomedical engineers to quickly design parts and try out a variety of metals at low cost. Kai Narita, PhD (PhD ’21), another member of the research team, has also turned this discovery into a business, 3D Architech.