Researchers at the University of Tokyo are using frog eggs to enhance what might seem like an unlikely element of robotics:olfactory sensing. By injecting the eggs with the DNA from various insects known for expressing keen senses of smell, the team was able to create a robotic nose that can detect molecules at levels as low as a few parts per billion. By injecting the eggs with DNA from fruit flies, silk moths, and diamond back moths, the bioengineers were able to coax the immature eggs into producing the olfactory sensors of those insects, which are known for their ability to detect specific gases and pheromones. The eggs were then fitted between two electrodes, creating a sensor system that measured the current generated when certain molecules came in contact with the detector.