Nanoscience is being used to exploit the natural light produced by fireflies in the hope of producing lights that glow without batteries or electricity. “Firefly light is one of nature’s best examples of bioluminescence,” said Mathew Maye, an assistant professor of chemistry at Syracuse University’s College of Arts and Sciences. “We’ve found a new way to harness biology for nonbiological applications by manipulating the interface between the biological and nonbiological components.” Produced in Maye’s laboratory, the custom quantum nanorods are 20 to 30 times more efficient than those created during previous experiments. Nanorods created with firefly enzymes glow orange. The custom, quantum nanorods are created in the laboratory of Mathew Maye, assistant professor of chemistry at Syracuse University. (Images: Syracuse U) Light is produced by fireflies through a chemical reaction between luciferin and its enzyme counterpart, luciferase. In the lab experiment, the enzyme is bonded to the nanorod’s surface, while luciferin acts as a fuel. The fuel and the enzyme interact, producing energy, which is transferred to the nanorods, causing them to glow. This process is called bioluminescence resonance energy transfer (BRET). “The trick to increasing the efficiency of the system is to decrease the distance between the enzyme and the surface of the rod and to optimize the rod’s architecture,” Maye said. “We designed a way to chemically attach genetically manipulated luciferase enzymes directly to the surface of the nanorod.” Maye’s collaborators at Connecticut College provided the genetically manipulated luciferase enzyme. The nanorods are composed of semiconductor metals: an outer shell of cadmium sulfide and an inner core of cadmium selenide. The color of the light can be changed by manipulating the rod length and the core size. Maye’s nanorods glowed green, orange and red in the laboratory — colors that are not possible for fireflies to produce (they naturally emit a yellowish glow). BRET scale was used to measure the efficiency of the system. The researchers observed that the most efficient rods (BRET scale of 44) had a special architecture called rod-in-rod, which emit light in the near-infrared range. Infrared illumination is important for applications such as night-vision goggles, cameras, telescopes and medical imaging. Nanorods created with firefly enzymes glow in a test tube. “The nanorods are made of the same materials used in computer chips, solar panels and LED lights,” Maye said. “It’s conceivable that someday firefly-coated nanorods could be inserted into LED-type lights that you don’t have to plug in.” Currently the firefly-conjugated nanorods exist only in the laboratory, but the scientists are working on methods to make them glow for longer periods of time and to scale up the system. Maye believes the system holds promise for future technologies that will convert chemical energy directly to light. “The nanorods are made of the same materials used in computer chips, solar panels and LED lights,” he said. “It’s conceivable that someday firefly-coated nanorods could be inserted into LED-type lights that you don’t have to plug in.” The work appeared online May 23 in Nano Letters. For more information, visit: www.syracuse.edu