Penn researchers working to mimic giant clams to enhance the production of biofuel

November 02, 2017

Alison Sweeney of the University of Pennsylvania has been studying giant clams since she was a postdoctoral fellow at the University of California, Santa Barbara. These large mollusks, which anchor themselves to coral reefs in the tropical waters of the Indian and Pacific oceans, can grow to up to three-feet long and weigh hundreds of pounds. But their size isn't the only thing that makes them unique.

Anyone who has ever gone snorkeling in Australia or the western tropical Pacific Ocean, Sweeney says, may have noticed that the surfaces of giant clams are iridescent, appearing to sparkle before the naked eye. The lustrous cells on the surface of the clam scatter bright sunlight, which typically runs the risk of causing fatal damage to the cell, but the clams efficiently convert the sunlight into fuel. Using what they learn from these giant clams, the researchers hope to improve the process of producing biofuel.

Sweeney, an assistant professor of physics in the Penn School of Arts and Sciences, and her collaborator Shu Yang, a professor of materials science and engineering in the School of Engineering and Applied Science, refer to the clams as "solar transformers" because they are capable of absorbing bright sunlight at a very high rate and scattering it over a large surface area. When the light is distributed evenly among the thick layer of algae living inside the clam, the algae quickly converts the light into energy.

"What those sparkly cells are doing," Sweeney says, "is causing light to propagate very deeply into the clam tissue and spread out."

After coming across Sweeney's work, Yang struck up a collaboration to see if they could mimic the system by abstracting the principles of the clam's process to create a material that works similarly. She and Ph.D. student Hye-Na Kim devised a method of synthesizing nanoparticles and adding them to an emulsion -- a mixture of water, oil, and soapy molecules called surfactants -- to form microbeads mimicking the iridocytes, the cells in giant clams responsible for solar transforming. Their paper has been accepted to Advanced Materials.

Sweeney compared the process to making a salad vinaigrette. The more a person shakes it, the smaller the oil droplets in the dressing. If one were to take nanoparticles, add them to the oil-water emulsion and shake it at the right speed, the droplet size can be controlled. After doing an optical characterization of the beads, the researchers found that they function very similarly to the clam cells.

Irodycites, the "sparkly" cells on the surface of clams, cause light to propagate very deeply into the clam tissue and spread out. When the light is distributed evenly among the thick layer of algae living inside the clam, the algae quickly converts the light into energy.

"It's very efficient, and it's very difficult to achieve," Yang says. "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."

The researchers' next step is to try to mimic the organization of the algae within the clams by getting algae to grow in gel pillars. Once they figure out how to do so, they hope to then marry their artificial iridocytes and the algae and measure the system to see if it can produce fuel to the same high efficiencies as the giant clam.

If successful, the method can be used for photosynthesis to enhance the efficiency of biofuel production. It can also be used in solar panels for generating, storing or preventing heat to allow for better temperature control in buildings.

"It's exciting to see the clever, non-intuitive ways that life has come up with to solve problems," Sweeney says. "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. It's figuring out these really clever design strategies that you wouldn't get to from a top-down human approach."
-end-
This research was supported by National Science Foundation/INSPIRE Grant No. IOS-1343159.

University of Pennsylvania

Related Nanoparticles Articles from Brightsurf:

An ionic forcefield for nanoparticles
Nanoparticles are promising drug delivery tools but they struggle to get past the immune system's first line of defense: proteins in the blood serum that tag potential invaders.

Phytoplankton disturbed by nanoparticles
Products derived from nanotechnology are efficient and highly sought-after, yet their effects on the environment are still poorly understood.

How to get more cancer-fighting nanoparticles to where they are needed
University of Toronto Engineering researchers have discovered a dose threshold that greatly increases the delivery of cancer-fighting drugs into a tumour.

Nanoparticles: Acidic alert
Researchers of Ludwig-Maximilians-Universitaet (LMU) in Munich have synthesized nanoparticles that can be induced by a change in pH to release a deadly dose of ionized iron within cells.

3D reconstructions of individual nanoparticles
Want to find out how to design and build materials atom by atom?

Directing nanoparticles straight to tumors
Modern anticancer therapies aim to attack tumor cells while sparing healthy tissue.

Sweet nanoparticles trick kidney
Researchers engineer tiny particles with sugar molecules to prevent side effect in cancer therapy.

A megalibrary of nanoparticles
Using straightforward chemistry and a mix-and-match, modular strategy, researchers have developed a simple approach that could produce over 65,000 different types of complex nanoparticles.

Dialing up the heat on nanoparticles
Rapid progress in the field of metallic nanotechnology is sparking a science revolution that is likely to impact all areas of society, according to professor of physics Ventsislav Valev and his team at the University of Bath in the UK.

Illuminating the world of nanoparticles
Scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) have developed a light-based device that can act as a biosensor, detecting biological substances in materials; for example, harmful pathogens in food samples.

Read More: Nanoparticles News and Nanoparticles Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.