Big Mac Ingredient Stabilizes Gold Nanoparticles

Researchers have discovered that gum arabic, a plant extract used to stabilize foods such as Big Macs, yogurt and soda, can be used to absorb and assimilate metals and create a "coating" that makes gold nanoparticles safe for nanomedicine applications.

Scientists think the future of cancer detection and treatment may lay in gold nanoparticles -- tiny pieces of gold so small they cannot be seen by the naked eye. Their potential as in vivo sensors, photoactive agents for optical imaging, drug carriers, contrast enhancers in computer tomography and x-ray absorbers in cancer therapy has been hindered by the difficulty of making them in a stable, nontoxic form that can be injected into a patient.

New research at the University of Missouri-Columbia (MU) has found that gum arabic can be used to overcome this problem, creating a new type of gold nanoparticle that is stable, safe and can be administered orally or injected.

Because gold nanoparticles have a high surface reactivity and biocompatible properties, they can be used for in vivo molecular imaging and therapeutic applications. The promise of nanomedicine comes from the high surface area and size relationships of nanoparticles to cells, making it possible to target individual cells for diagnostic imaging or therapy.

Kattesh Katti, MU professor of radiology and physics and director of the University of Missouri Cancer Nanotechnology Platform, worked with other MU scientists in the fields of physics, radiology, chemistry and veterinary medicine. The team tested plant extracts for their ability as nontoxic vehicles to stabilize and deliver nanoparticles for in vivo nanomedicinal applications.

The researchers became interested in gum arabic, a substance taken from species of the acacia tree, because it is already used to stabilize foods. Gum arabic has unique structural features, including a highly branched polysaccharide structure consisting of a complex mixture of potassium, calcium and magnesium salts derived from arabic acid. The scientists found that gum arabic could be used to absorb and assimilate metals and create a "coating" that makes gold nanoparticles stable and safe.

Katti and Raghuraman Kannan, assistant professor of radiology, have been collaborating on the development of biocompatible gold and silver nanoparticles for medical applications.

"We found that gum arabic can effectively 'lock' gold nanoparticles to produce nontoxic, nanoparticulate constructs that can be used for potential applications in nanomedicine," Katti said. "We have developed a new class of hybrid gold nanoparticles that are stable and can be administered either orally or through intravenous injection within the biological system."

This finding could lead to the development of readily injectable gold nanoparticles. Mansoor Amiji, professor of pharmaceutical sciences in the Bouve College of Health Sciences' School of Pharmacy and co-director of the Nanomedicine Education and Research Consortium at Northeastern University in Boston, said this represents a major scientific discovery that will initiate a new generation of biocompatible gold nanoparticles.

"The excellent in vivo stability profiles of such gold nanoconstructs will open up new pathways for the intratumoral delivery of gold nanoparticles in diagnostic imaging and therapeutic applications for cancer," Amiji said.

A paper describing the team's findings was published in the February edition of the journal Small. Katti's collaborators on this paper include Casteel, Kannan, David Robertson, Evan Boote, Genevieve M. Fent, Kavita Katti, Vijaya Kattumauri and Meera Chandrasekhar.

The work has been supported with a grant from the National Institutes of Health/National Cancer Institute under the Cancer Nanotechnology Platform program.

For more information, visit: www.mizzou.edu