A perfectly gross method of making biological electronics, and sidestepping the problem of electronic waste:
A group of researchers from Tel Aviv University are working on protein-based transistors made up of human blood, mucus, and milk. When proteins from these three substances are applied to a base material, they create a semiconducting film–a complete circuit with both optical and electronic capabilities.
Why blood, mucus, and milk? Milk makes up the “building blocks” of the transistor (these proteins are strong in harsh environments), mucus protein keeps different colored dyes separate, and blood’s oxygen-absorbing ability makes it possible to add chemicals to the semiconductor to create different capabilities.