I.e., we made an active device, a bistable switch. Computers are nothing but arrays of bistable switches. This was a significant advance over passive doping, which you can also do with the melanins. Ironically, we considered this of little import in view of an active device. Nearly a decade passed before there was another report of an organic semiconductor used in an active device, a field-effect transistor.
Some melanins even emit a flash of light as they switch, implyng possible electroluminesence.