Where you could use a protein switch is still an open question. One obvious answer is in electronic detectors that find things like contaminants in water, pollutants in the air, or chemical signs of illness in people. Find a protein that reacts to the chemical you're interested in, measure the protein's electrical changes, and voilà, you've got a protein-based electronic detector. This could be another approach to the electronic noses researchers have developed in recent years. Protein-based devices would have one major challenge to overcome, however. They would have to find a way to keep potentially delicate proteins intact and functional inside a silicon gadget.