One promising early experiment we did was to check whether it was possible to indigo-dye silk hydrogel. Just scooping some globs out of a tube of silk fibroin solution that had gelled on its own (“expired”), it worked just to immerse those in a small tube of indigo dyeing solution (indigo pigment reduced to water-soluble form using fructose as the reducing agent and sodium hydroxide as the base) for ten minutes, then rinsing several times with water.