Nanoparticles Can Now Kill Brain Tumor Cells

At the same time, they leave healthy cells intact

By Tudor Vieru on August 24th, 2009 19:01 GMT
When treating cancer in the brain, delicacy is the operative word. Any and all methods of treatment, be they chemotherapy, surgery or nanoparticle-based alternatives, need(s) to be able to target the diseased cells specifically, and leave the surrounding networks of neurons undamaged. A newly devised technique does just that. It relies on inorganic titanium dioxide nanoparticles, which are bound to a soft biological material before being inserted at the site of the tumor, ScienceDaily reports.

“It is a real example of how nano and biological interfacing can be used for biomedical application. We chose brain cancer because of its difficulty in treatment and its unique receptors,” Elena Rozhkova, who is a scientist at the US Department of Energy's (DOE) Argonne National Laboratory (ANL) Center for Nanoscale Materials says.

Experts from the Brain Tumor Center at the University of Chicago (UC) have also participated in the research. The method is published in the latest issue of the respected scientific journal Nano Letters.

“The significance of this work lies in our ability to effectively target nanoparticles to specific cell surface receptors expressed on brain cancer cells. In so doing, we have overcome a major limitation involving the application of nanoparticles in medicine, namely the potential of these agents to distribute throughout the body. We are now in a position to develop this exciting technology in pre-clinical models of brain tumors, with the hope of one day employing this new technology in patients,” UC-BTC Director of Neurosurgical Oncology Dr. Maciej S. Lesniak adds.

The new approach is a work of genius in its simplicity. Biological molecules known as antibodies are attached to titanium oxide nanoparticles, which are sensible to light. The antibodies bind to specific locations on the surface of cancerous cells. After this step of the process is done and all nanoparticles have reached their targets, beams of light are shone on the titanium oxide. It responds by releasing free oxygen radicals.

These radicals interact with the mitochondria – the cellular power plant – in cancer cells. When the small structures detect oxygen radicals around them, they start releasing death signals, which kill the cancer cell from within. The results were amazing. Within six hours of shining light on the cells, almost 100 percent of them showed an elevated cell toxicity rate. The rate dropped to 80 percent after 48 hours. Undoubtedly, further enhancements to this method will result in a formidable weapon against brain tumors, which claim thousands of lives each year.
X-ray fluorescent imaging of the TiO2-mAb binding to the single brain cancer cells
   X-ray fluorescent imaging of the TiO2-mAb binding to the single brain cancer cells