Carbon nanotubes attached to antibodies kill cancer cells under infrared light
25 June 2008
Carbon nanotubes attached to antibodies can kill cancer cells by heating up when exposed to near-infrared light. Biomedical scientists at University of Texas Southwestern Medical Center and nanotechnology experts from UT Dallas describe their experiments in the Proceedings of the National Academy of Sciences.
The researchers used monoclonal antibodies that targeted specific sites on lymphoma cells to coat the carbon nanotubes. Carbon nanotubes are very small cylinders of graphite carbon that heat up when exposed to near-infrared light. Near-infrared light can penetrate human tissue up to about 1½ inches.
In cultures of cancerous lymphoma cells, the antibody-coated nanotubes attached to the cells’ surfaces. When the targeted cells were then exposed to near-infrared light, the nanotubes heated up, generating enough heat to essentially 'cook' the cells and kill them. Nanotubes coated with an unrelated antibody neither bound to nor killed the tumour cells.
“Using near-infrared light for the induction of hyperthermia is particularly attractive because living tissues do not strongly absorb radiation in this range,” said Dr. Ellen Vitetta, director of the Cancer Immunobiology Center at UT Southwestern and senior author of the study. “Once the carbon nanotubes have bound to the tumour cells, an external source of near-infrared light can be used to safely penetrate normal tissues and kill the tumour cells.
“Demonstrating this specific killing was the objective of this study. We have worked with targeted therapies for many years, and even when this degree of specificity can be demonstrated in a laboratory dish, there are many hurdles to translating these new therapies into clinical studies. We’re just beginning to test this in mice, and although there is no guarantee it will work, we are optimistic.”
The use of carbon nanotubes to destroy cancer cells with heat is being explored by several research groups, but the new study is the first to show that both the antibody and the carbon nanotubes retained their physical properties and their functional abilities — binding to and killing only the targeted cells. This was true even when the antibody-nanotube complex was placed in a setting designed to mimic conditions inside the human body.
Biomedical applications of nanoparticles are increasingly attracting the attention of basic and clinical scientists. There are, however, challenges to successfully developing nanomedical reagents. One is the potential that a new nanomaterial may damage healthy cells and organisms. This requires that the effects of nanomedical reagents on cells and organisms be thoroughly studied to determine whether the reagents are inherently toxic.
“There are rational approaches to detecting and minimizing the potential for nonspecific toxicity of the nanoparticles developed in our studies,” said Dr Rockford Draper, leader of the team from UT Dallas and a professor of molecular and cell biology.
