Nanotech News

January 9, 2006

Nanoparticles Provide View of Drug Delivery into the Brain

At the boundary between the brain and the body lies a tightly knit set of cells, known as the blood-brain barrier, that helps protect the brain from infection or exposure to potentially harmful molecules. Unfortunately, the blood-brain barrier also blocks most anticancer drugs from entering the brain, making it difficult to treat brain cancer and spurring researchers to search for methods of breaching the blood-brain barrier without damaging it. One such technique, known as convention-enhanced delivery, or CED, has shown initial promise in human clinical studies, and investigators are now attempting to improve this method.

Caption: A real-time MR image shows gadolinium-loaded nanoparticles that have diffused through two different regions of the brain when administered using convection-enhanced delivery. Courtesy of Dr. Krystof Bankiewicz, University of California, San Francisco. Caption: Real-time magnetic resonance image showing gadolinium-nanoparticle formulation diffusing through a small region of the brain. Courtesy of Dr. Krystof Bankiewicz, University of California, San Francisco.

To help these efforts, a group of investigators led by Krystof Bankiewicz, M.D., and Tracy McKnight, Ph.D., at the University of California, San Francisco (UCSF), has turned to nanoparticles in order to visualize how drug travels through the brain when administered using CED. In a paper published in the journal Experimental Neurology, the UCSF team shows how liposomes loaded with gadolinium can provide detailed magnetic resonance images of drug moving through a living primate brain following CED.

The investigators tracked the distribution of gadolinium-containing liposomes using real-time magnetic resonance imaging (MRI). Liposomes were detected in targeted brain regions between 10 to 20 minutes following injection. The investigators note that the MR images were highly accurate at determining tissue distribution. Based on the results of their experiments in non-human primates, the researchers conclude that nanoparticle technology combined with MRI and CED may provide new opportunities for treating human brain tumors.

This work, funded in part by the National Cancer Institute, is detailed in a paper titled, “Gadolinium-loaded liposomes allow for real-time magnetic resonance imaging of convection-enhanced delivery in the primate brain.” An abstract is available through PubMed.
View abstract.