Researchers at the Bio-SANS instrument at the High Flux Isotope Reactor are getting a leg up in their research from an ingenious "low tech" lighting tool that can be fixed to their samples and then pushed directly into the neutron beam, to illuminate the response of layers of cyanobacteria to changes in light.
"It's really low tech," says Volker Urban, lead instrument scientist on the Bio-SANS, with a grin. "You can buy the parts anywhere." The lighting tool is the work of graduate student Brad O'Dell, a visiting intern from Cambridge University in the United Kingdom. The device combines light emitting diodes with the electronics that drive the illumination.
Parts off the shelf it may be, but the device facilitates research into biologically inspired solar cell devices, important alternative energy- related research being conducted with funding from the Photosynthetic Antenna Research Center, one of the Energy Frontier Research Centers in the US.
Photosynthesis is the process by which plants convert sunlight into energy. Bacteria, algae and plants have natural sensors called light-harvesting antenna systems that capture the sun's light and transfer the energy to reaction centers, where the electron transfer for photochemistry occurs. Such antenna complexes are highly specialized in nature, allowing organisms to capture the maximum light energy available in their environment.
Researchers at the Bio-SANS are now using the new LED lighting tool to study the light response of the membrane stacks in cyanobacteria, a blue-green algae found in almost every environment, from oceans to fresh water to bare rock to soil.
At the Bio-SANS, the bacteria are loaded into cuvettes, small sample holders that resemble tiny transparent banjos. An LED is fixed to the top of each cuvette. The array is then pushed into the sample holder and the neutron beam passes through a window, taking "pictures" of the response of the layers of the bacteria to variations in light from the attached LEDs.
"We push the samples into the neutron beam - and then from the neutron scattering we can observe how the structure changes, depending on how much light of which color we shine on the samples," Urban said. "Ultimately, we want to find out how nature has solved the problem of optimizing the efficient use of solar energy through these intricate architectures of antennas. These collect sunlight and funnel the light energy to reaction centers, where it is converted into chemical energy that can be stored for further use," he said. "If those fundamental principles are better understood then they can be used to create new, more efficient solar panels."