Scientists from the University of Missouri encased gold nanoparticles (AuNPs) with gum-arabic matrix, a natural phytochemical, and made such particles nontoxic, thus making them potentially useful for diagnostic and therapeutic applications in nanomedicine:
Writing about their studies in the journal Small, the investigators reasoned that gum arabic, a natural polymer made of sugars and some protein, would bind tightly to gold nanoparticles because of its chemical composition. Sure enough, the researchers found that simply mixing a commercially available gold salt with a dilute solution of gum arabic and a chemical-reducing agent resulted in the nearly instantaneous formation of gum arabic-labeled gold nanoparticles. The investigators noted that over 98 percent of the gold salt was converted to gum arabic-labeled gold nanoparticles. The resulting nanoparticles were stable in biological fluids for at least seven days.
Next, Katti and his collaborators studied biodistribution properties of these nanoparticles following intravenous injection into pigs. These experiments confirmed that gum arabic could effectively stabilize gold nanoparticles in the body. This study also found that most of the nanoparticles accumulated in the liver and lungs.
Preliminary imaging studies showed that the gum arabic-labeled gold nanoparticles could function as x-ray imaging contrast agents. As part of these experiments, the investigators compared the signal enhancement produced by the gold nanoparticles with that generated by iodine-containing compounds used today as CT imaging contrast-enhancing agents.