Rice, MD Anderson researchers refine the technique to attack hard to reach tumors

Rice, MD Anderson researchers refine the technique to attack hard to reach tumors -

Short, custom carbon nanotubes have the potential to provide drugs to pancreatic cancer cells and destroy them from within, according to researchers at Rice University and the University of Texas MD Anderson cancer Center.

nanotubes Pristine products through a new process in moss can be modified to carry drugs to tumors through gaps in the walls of blood vessels that larger particles can not not get through

nanotubes can then target and infiltrate the nuclei of cancer cells, where drugs can be released by sonication - .. that is, shaking

directed research rice chemist Andrew Barron has been reported in the Royal Society of Chemistry Journal of Materials Chemistry B .

cancer patients most of the pancreas die within a year of diagnosis and have a five year survival rate of 6 percent, partly because there is no method for early detection, according to the American Cancer Society. The tumors are often inoperable and pancreatic cancer cells are also difficult to reach with chemotherapy, said co-author Jason Fleming, professor of surgical oncology at MD Anderson.

"These results are encouraging because they offer a potential delivery solution for patients with cancer of the pancreas with tumors resistant to standard chemotherapy," said Fleming. "There are molecular and biological barriers the effective delivery of chemotherapy for tumors of pancreatic cancer, and these nanotubes may be able to do some of those irrelevant. "

the rice scientists made sufficiently pure nanotubes to change profit and small enough to slip through the defenses of the body, Barron said the researchers knew of previous work that the nanotubes could be modified. - a process called functionalization. - When carrying chemotherapy agents and release at a controlled rate by sonication

"This time, we tried to work on the length of the tubes should be and the extent of functionalization maximize absorption by the cells," said Barron.

Several discoveries were the key, he said. First, the rice graduate student, former student and co-author Alvin Orbaek purified iron catalysts of carbon nanotubes need to grow by rinsing with chlorine. "Iron particles Leftover damage the tubes by oxidation," Barron said. "This makes it difficult for future use."

The next step was to cut the nanotubes to size. Very long nanotubes are floppy and difficult to treat, Barron said. Enrico Andreoli, a postdoctoral research associate in the group and the Barron lead author of the paper, used a thermal process to chop an average length of 50 nanometers. (A human hair is about 100,000 nanometers wide.)

"Instead of experiencing a nanotube powder fluffy, we get something that looks like a hockey puck," said Barron. "It's very dense - it looks like a sponge washer - .. But you can cut it with a razor blade can weigh and make accurate chemistry with her"

Laboratory Barron added polyethyleneimine (PEI) to the nanotube

surfaces. in laboratory tests, the tubes were modified easily dispersed in a liquid and able to pass through the barriers in living cancer cells to infiltrate the nuclei. a small molecule variant of PEI turned out to be less toxic to cells than larger versions, Barron said.

"This research shows that the particles are small enough to penetrate inside cells where you want them and they may have increased benefit kill - but it is still unknown, "said Fleming

Fleming, whose work focuses on improving the administration of medication for pancreatic cancer, has warned that more research is needed .. "the next step will be to test this approach in mice that have allografts taken from human tumors," he said. "The architecture of these tumors look more like that of human pancreatic cancer."