Nanoscopic 'pearl necklaces' track and attack cancer cells

A team of investigators at Purdue University has developed nanoscale probes that can help pinpoint the location of tumors and might one day be able to directly attack cancer cells.

Joseph Irudayaraj, Ph.D., led the team that developed the tumor-targeting multifunctional probes. "If we have a tumor, these probes should have the ability to latch on to it," Dr. Irudayaraj said. "The probe could carry drugs to target, treat, and reveal cancer cells." This study appears in the journal Angewandte Chemie International Edition.

Researchers have developed probes that use either gold nanorods or magnetic iron oxide nanoparticles, but Dr. Irudayaraj's nanoprobes use both, making them easier to track with different imaging devices as they move toward cancer cells. The magnetic iron oxide particles can be traced using magnetic resonance imaging (MRI), whereas the gold nanorods are luminescent and can be traced through microscopy, a more sensitive and precise process. Dr. Irudayaraj noted that an MRI is less precise than optical luminescence in tracking the probes but has the advantage of being able to track them deeper in tissue, expanding the probes' possible applications. The gold nanorods act as the "string," while the iron oxide nanoparticles, which are linked to the nanorods, serve as the "pearls."

The probes contain the antibody herceptin, which is used in the treatment of metastatic breast cancer. Experiments demonstrated that these probes targeted and were taken up by cultured breast cancer cells expressing the Her-2 protein. The investigators also showed that the nanoprobes, when illuminated with near-infrared light, could serve as photothermal anticancer agents. The investigators are now working to add additional anticancer agents to these nanoscale constructs.

This work is detailed in the paper "Gold nanorod/Fe₃O₄ nanoparticle 'nano-pearl-necklaces' for simultaneous targeting, dual-mode imaging, and photothermal ablation of cancer cells." An abstract of this paper is available at the journal's Web site. View abstract