In a new study published in Advanced Materials, researchers are studying giant clams in a bid to enhance biofuel production.
Giant clams can absorb bright sunlight at a very high rate and the lustrous cells on the clam’s surface scatter it over a large surface area.
"What those sparkly cells [on the clam] are doing is causing light to propagate very deeply into the clam tissue and spread out," said Alison Sweeney, an assistant professor of physics in University of Pennsylvania's School of Arts and Sciences. She calls the process "solar transforming."
When the light is distributed evenly among the thick layer of algae living inside the clam, the algae converts the light into energy.
Sweeney's collaborator Shu Yang, a professor of materials science and engineering in the School of Engineering and Applied Science, also worked with Ph.D. student Hye-Na Kim to work out a method of synthesising nanoparticles and adding them to an emulsion (comprising water, oil, and soapy molecules called surfactants) to form microbeads mimicking iridocytes (those sparkly iridescent cells responsible for solar transforming).
By shaking the resultant mixture at the right speed, the size of the droplets can be controlled. An optical characterisation of the beads showed that they functioned quite similarly to clam cells.
According to Yang, it is very efficient, though hard to achieve. "People are trying to do this by designing nanoparticles, but you need to do a lot of synthesis and find ways to precisely control their size, shape and optical properties, which becomes complicated and expensive. Our method is both simple and inexpensive and at the same time achieves better results than all these other systems,” she said.
The team will try to mimic the organisation of the algae by getting it to grow in gel pillars. Once they succeed, they will marry the artificial iridocytes and the algae, and then see if the fuel that results has the same level of efficiency as the giant clam.
If the method proves successful, the new technology can be used in solar panels and also for photosynthesis to enhance the efficiency of biofuel production.
"It's exciting to see the clever, non-intuitive ways that life has come up with to solve problems," Sweeney said. "Typically, evolution is a lot more clever than human engineers, and the trick is to ask smart questions about what design problem is being solved in each evolutionary case."