Carbon nanotubes attached to antibodies kill cancer cells under
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
“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.