The sea slug Aplysia californica is a slimy, homely creature that can be found at low tide along the California shore.
When this creature feels threatened in its underwater habitat, it releases a bright purple ink laced with anti-predator chemicals.
Georgia State researchers are studying the powerful antimicrobials in that ink and developing applications that could serve the medical and shipping industries.
Charles Derby, Eric Gilbert, Phang C. Tai and Binghe Wang believe they can use the ink's active ingredient to solve problems that, on the surface, seem unrelated – promoting better healing of wounds and preventing barnacles from attaching to the hulls of ships.
They are targeting biofilms, populations of cells that grow on a surface and are tightly connected, making them difficult to remove and sometimes allowing infections to take hold.
“There’s a huge interest in developing products for that,” Derby said.
In fact, the demand for disinfectant and antimicrobial chemicals in the United States is expected to rise 6.1 percent annually to $1.6 billion in 2017, according to the Freedonia Group, an international business research company.
In the shipping industry, studies have found that the drag created by barnacles growing on ships’ hulls can increase fuel costs by 40 percent.
The researchers want to coat the surfaces of ships and piers to prevent and break down barnacles and worms, which begin to grow after biofilm has formed. The paints now used to prevent biofilms contain heavy metals, making them toxic to the environment and potentially dangerous to humans who could absorb the toxins by eating tainted shellfish.
In healthcare, the researchers hope to prevent and break down biofilms on human tissue, such as wounds, possibly embedding the active ingredient in a bandage or applying it with a spray.
Antimicrobials that work in new ways are needed because the overuse of some bacteria-killing products has led to drug resistance. Derby said the group’s new product could also be used for treating tabletops and medical and cleaning supplies.
Ten years ago, P.M. Johnson, Hsiuchin Yang, Ko-Chun Ko, and other colleagues under the direction of Derby and Tai discovered the purple ink from this species of sea slug, also known as a sea hare, contains an enzyme called escapin, which produces antimicrobial molecules. The ink also contains L-Lysine, the molecule that escapin bonds to in order to act. With Wang’s help, the group learned how to synthesize the active ingredient in the lab.
The challenge is that it quickly breaks down into a less effective compound.
“That’s kind of a pain actually, but that’s also what makes us excited because these are very reactive molecules,” Derby said. “If they’re in water at room temperature, the molecules are not stable. They have their effect, but very briefly. We’re identifying the conditions whereby we can hold these molecules as commercial products.”
The researchers have found that mixing the molecules with hydrogen peroxide can be effective for some uses. But this might not be needed for human wounds because immune cells migrate to the site of the injury, where the body naturally produces hydrogen peroxide.
The researchers received in March a provisional patent for their work with the synthetic molecules and biofilms and they are applying for a full patent. They have two other patents for related work.
Ripple Management, a technology commercialization company with a specialty in the life sciences, is helping the researchers to develop a business plan and advising them on experiments to perform to keep moving toward commercialization. The researchers are considering whether to form their own company or find someone to license and develop their product. The partnership is funded by a Georgia Research Alliance Ventures grant.
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