Smell, taste, sight, sound, and touch. Our bodies are natural biosensors and highly sensitive to chemicals and dangers we commonly encounter in the environment. Food tastes disgusting, rot smells bad hot things burn, yellow and black suggest danger, and unusual sounds create suspicion, so why should we need to develop biosensors that do these functions for us? The answer is simple. Our world has changed faster than our senses have adapted. In the last 300 years technology has reformed our environment. We now have high quantities of poisons we can’t taste, creatures we can’t see, and gases we can’t smell. Methane and carbon monoxide are odorless and clear and colorless. Our bodies are unable to recognize them. Micro-concentrations of dangerous chemicals even with odor or taste are undetectable without external biosensors. These biosensors have the potential to save lives by finding these threats before they make an impact. Diseases could be cured faster and countermeasures can be prepared to prevent disaster. Biosensors are needed to protect people from the consequences of a technologically advancing society.