Nanotech News

June 6, 2005

Iron Oxide Nanoparticles Deliver Anticancer Agents

Magnetic nanoparticles have shown promise as contrast-enhancing agents for improving cancer detection using magnetic resonance imaging, as miniaturized heaters capable of killing malignant cells, and as targeted drug delivery vehicles. Now, researchers at the University of Nebraska have developed a novel coating for magnetic nanoparticles that allows the particles to carry large amounts of drug and to disperse efficiently in water. This development may enable targeted delivery of water-insoluble anticancer agents or imaging agents.

Writing in the journal Molecular Pharmaceutics, a group headed by Vinod Labhasetwar, Ph.D., at the University of Nebraska Medical Center, and Diandra Leslie-Pelecky, Ph.D., of the University of Nebraska-Lincoln, report on its development of a multi-component coating system for iron oxide nanoparticles that does not diminish the magnetization of the core particle. The coating is formed by layering oleic acid onto the core nanoparticle and then adding a polymer known as PluronicT, consisting of alternating segments of polyethylene oxide and polypropylene oxide. The oleic acid layer solubilizes and holds water-insoluble drugs, while the polymer layer acts as a surfactant that enables the nanoparticles to disperse in water. Coating the iron oxide nanoparticles in this manner actually increased their magnetization.

To model the particles drug-carrying and drug-releasing characteristics, the investigators loaded the nanoparticles with the poorly soluble drug doxorubicin. They measured uptake of the drug by several cultured cancer cell lines in addition to cytotoxicity following drug administration. Approximately 28 percent of the drug was released over two days, and about 68 percent was released over one week. The researchers observed that the drug-loaded nanoparticles caused dose-dependent cytotoxicity.

This work is detailed in a paper titled, "Iron Oxide Nanoparticles for Sustained Delivery of Anticancer Agents." This paper has been posted online at the journal's website in advance of publication. An abstract of the paper is available there.
View abstract.