Syracuse University Magazine

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For chemistry professor Mathew Maye and chemistry doctoral candidate Rabeka Alam (pictured), it’s all about the size and structure of the custom, quantum nanorods produced in Maye’s laboratory.

Photos by Steve Sartori



Firefly Power

What do fireflies, nanorods, and Christmas lights have in common? More than you might think, since someday consumers may be able to purchase multicolor strings of light that don’t need electricity or batteries to glow. Using nanoscience, scientists in the College of Arts and Sciences have created a new method for harnessing bioluminescence—the natural light produced by fireflies. Their breakthrough produces a system 20 to 30 times more efficient than those produced during previous experiments.

For chemistry professor Mathew Maye and chemistry doctoral candidate Rabeka Alam, it’s all about the size and structure of the custom, quantum nanorods produced in Maye’s laboratory. “Firefly light is one of nature’s best examples of bioluminescence,” says Maye, a member of the Syracuse Biomaterials Institute. “The light is extremely bright and efficient. We’ve found a new way to harness biology for nonbiological applications by manipulating the interface between the biological and nonbiological components.”

Documentation of their work, “Designing Quantum Rods for Optimized Energy Transfer with Firefly Luciferase Enzymes,” was published in a recent edition of Nano Letters, a premier journal of the American Chemical Society. They collaborated on the research with Connecticut College professor Bruce Branchini.

Fireflies produce light through a chemical reaction between luciferin and its counterpart, the enzyme luciferase. In Maye’s laboratory, the enzyme is attached to the nanorod’s surface; luciferin, which is added later, serves as the fuel. The energy released in the interaction is transferred to the nanorods, causing them to glow—a process 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,” says Maye, whose research was funded by a Department of Defense PECASE award sponsored by the Air Force Office of Scientific Research (AFOSR). “We designed a way to chemically attach genetically manipulated luciferase enzymes directly to the surface of the nanorod.”

The nanorods are composed of semiconductor metals, featuring an outer shell of cadmium sulfide and an inner core of cadmium selenide. Manipulating the size of the core and the length of the rod alters the color of the light produced. Maye’s nanorods glow green, orange, and red—colors not possible for fireflies, which naturally emit a yellowish glow. The efficiency of the system is measured on a BRET scale. The researchers found their most efficient rods (BRET scale of 44) occurred for a special rod architecture (called rod-in-rod) that emitted light in the near-infrared light range.

Maye’s and Alam’s firefly-conjugated nanorods currently exist only in their chemistry laboratory. Additional research is ongoing to develop methods of sustaining the chemical reaction—and energy transfer—for longer periods of time and to “scale up” the system. Maye believes the system holds the most promise for future technologies that will convert chemical energy directly to light; however, the idea of glowing nanorods substituting for LED lights is not the stuff of science fiction. “The nanorods are made of the same materials used in computer chips, solar panels, and LED lights,” Maye says. “It’s conceivable that someday firefly-coated nanorods could be inserted into LED-type lights that you don’t have to plug in.” —Judy Holmes



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