Nanostructures Protect Healthy Cells from Radiation Damage

[grantnano]

Scientists at the University of Central Florida Use Nanostructures to Protect Healthy Cells from Radiation Damage

Working from an observation that nanoparticles, but not microparticles, extend the lifespan of cells grown in culture by acting as a powerful antioxidant, researchers at the University of Central Florida have developed nanostructures made of cerium oxide that can protect cells from intense radiation. Such particles could prove useful in sparing healthy cells during radiation therapy to treat cancer.

Writing in the journal Nano Letters, a research team led by Roy Tarnuzzer, Ph.D., described the technique it used to create 2 to 5 nanometer diameter cerium oxide nanoparticles that contained cerium atoms in two different electronic states. It is the presence of both electronic states – only one or the other is present in larger particles – that gives the nanoscale material its antioxidant properties, according to the investigators.

During radiation therapy, a focused beam of high-energy ionizing radiation bombards a tumor. Unfortunately, healthy tissue surrounding the tumor, even if it doesn’t directly receive radiation, can suffer damage and death, too. Radiation is thought to be toxic to these healthy cells through a process called oxidative damage - irradiated cells release reactive oxygen species as they die, and these reactive oxygen species can trigger a series of events that cause neighboring cells to die.

To determine if cerium oxide nanoparticles could stop oxidative damage, and potentially spare healthy cells from radiation damage, Dr. Tarnuzzer and his colleagues incubated both normal breast cells and malignant breast cells with the cerium nanoparticles for 24 hours. The nanoparticles themselves were non-toxic to either type of cell, but when the two types of cells were then treated with high-dose radiation, only the breast cancer cells were killed. In contrast, almost 100 percent of the normal breast cancer cells survived a normally lethal dose of radiation.

Additional research showed that healthy cells take up more of the cerium nanoparticles than do the malignant cells. The investigators note, too, that nanoscale cerium oxide particles are long-lived and thus would be able to confer radioresistance with a single dose.

This work is detailed in a paper titled, “Vacancy engineered ceria nanostructures for protection from radiation-induced cellular damage.” This work was published online in advance of print publication. An abstract is available at the journal’s website.

Source: NCI Alliance for Nanotechnology in Cancer.

URL: http://nano.cancer.gov/news_center/nanotech_news_2005-12-19a.asp

This story was posted on 20 December 2005.