Nanobombs aim to eradicate cancer

Source:
http://www.scienceblog.com/cms/nanobombs_aim_to_eradicate_cancer_9083

Nanobombs aim to eradicate cancer

University of Delaware researchers are opening a new front in the war on
cancer, bringing to bear new nanotechnologies for cancer detection and
treatment and introducing a unique nanobomb that can literally blow up
breast cancer tumors.

Balaji Panchapakesan, assistant professor of electrical and computer
engineering at UD, has recently reported on the discoveries in the
journals NanoBiotechnology and Oncology Issues.

He is the lead investigator for a team that includes Eric Wickstrom,
professor of biochemistry and molecular biology at Thomas Jefferson
University in Philadelphia and his student Greg Cesarone, and UD graduate
students Shaoxin Lu, Kousik Sivakumar and postdoctoral researcher Kasif
Teker.

Panchapakesan said this is basic research in the very early stages of
inquiry and that it would take extensive testing and years of clinical
trials before the nanobombs could actually be used in medical applications
to treat human beings.

“Make no mistake, we are focused on eradicating cancer,” Panchapakesan
said, explaining that the nanobombs are the result of work over the past
two years with carbon nanotubes, which are atoms of carbon arranged in
tubular form.

Originally, he said, the research team was looking at the use of the
carbon nanotubes as drug delivery vehicles. Because they are smaller than
the size of a single cell, the nanotubes can provide for the highly
selective injection of drugs into individual cells.

As they undertook various experiments, however, the team made a startling
discovery. “When you put the atoms in different shapes and forms, they
take on different properties at the nanoscale,” Panchapakesan said. “We
were experimenting with the molecules and considering optical and thermal
properties, and found we could trigger microscopic explosions of nanotubes
in wide variety of conditions.”

Explosions in air of loosely packed nanotubes have been seen before in an
oxygen environment, creating ignition. However, the work reported by
Panchapakesan uses the localized thermal energy imbalance to set off
explosions that are intrinsic in nature.

Panchapakesan said the nanobombs are just that, tiny bombs on the
nanoscale. “They work almost like cluster bombs,” he said. “Once they are
exposed to light and the resulting heat, they start exploding one after
another.”

The bombs are created by bundling the carbon nanotubes. With a single
nanotube, the heat generated by the light is dissipated by surrounding
air. In bundles, the heat cannot dissipate as quickly and the result is
“an explosion on the nanoscale,” Panchapakesan said.

When the UD researchers saw the explosions, they realized it might be
possible to use the microscopic bombs to kill cancer cells. They recreated
the explosions in solutions including water, phosphate and salt, which
meant the nanobombs could be used in the human body. In fact the
explosions were more dramatic in saline solutions, Panchapakesan said.

“The nanobomb is very selective, very localized and minimally invasive,”
Panchapakesan said. “It might cause what I would call nanopain, like a pin
prick.”

He believes the nanobomb holds great promise as a therapeutic agent for
killing cancer cells, with particular emphasis on breast cancer cells,
because its shockwave kills the cancerous cells as well as the biological
pathways that carry instructions to generate additional cancerous cells
and the small veins that nourish the diseased cells. Also, it can be
spread over a wide area to create structural damage to the cancer cells
that are close by.

The nanobombs are superior to a variety of current treatments because they
are powerful, selective, non-invasive, nontoxic and can incorporate
current technology, including microsurgery.

An advantage over other carbon nanotube treatments being considered by
scientists is that with nanobombs, the carbon nanotubes are destroyed
along with the cancer cells. Once the nanobombs are exploded and kill
cancer cells, macrophages can effectively clear the cell debris and the
exploded nanotube along with it.

Other treatments retain the carbon nanotubes and nanoparticles intact. If
the material finds its way to the kidney or accumulates in the blood
vessels, the nanoparticles might cause blockage and create problems,
Panchapakesan said. Furthermore, the nanobomb route is probably the only
way to use nanotubes without any cytotoxicity as the nanotubes are
destroyed completely.

Current surgical techniques are not precise and cancerous cells are often
left behind. In addition, cancers in some part of the body, such as
arteries and veins, are sometimes considered inoperable. Nanobombs can be
used to target any remaining cancerous cells and can be used in any part
of the body, allowing the creation of nanobomb therapy for a wide variety
of cancers.

Panchapakesan said the method is far better than modern chemotherapy,
which is non-selective, kills normal cells as well as cancerous cells and
leads to a decline in the quality of life for the patient. “This is
valuable in patient management, pain management and overall quality of
life,” he said.

Furthermore, Panchapakesan said, the nanobomb is a “very simple technique”
and as such will likely prove to be “more robust and with the best chance
to succeed.”

Panchapakesan added, “We are just getting started in this area. There is
plenty of work ahead to successfully translate this into clinical
medicine.”

In addition to treatment, he believes nanotechnology can provide new tools
for cancer diagnosis through the use of tiny nanosensors.

“In the future, my vision is that people will have at-home kits that can
detect cancer. After work they will be able to go to a clinic, be treated
with nanobombs and go home,” Panchapakesan said. While these initial
experiments are on breast cancer cells, he is also working to extend his
method to prostate cancer and pancreatic cancer.

He also foresees nano-bio-robots or nano-surgical tools that can be placed
inside the body to remove tumors in areas previously inaccessible using
traditional treatment methods.

Panchapakesan said the team’s findings are the result of interdisciplinary
research. “Different sciences come together to make this work,” he said,
citing cancer biology, physics, electrical and computer engineering and
chemistry. “Interdisciplinary research provides for fresh perspectives and
brings about new ideas, which is probably the way to go in the future.”

Funding for the research was provided in part by the Department of
Defense’s Congressionally Directed Medical Research Program.

Panchapakesan received his bachelor’s degree in materials engineering at
Regional Engineering College in India and doctorate in mechanical
engineering from the University of Maryland at College Park in 2001 before
joining the faculty at UD. His work is in the area of micro- and
nano-electromechanical systems (MEMS),
nanotechnology and biomedical research.

From University of Delaware

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Submitted by BJS on Fri, 2005-10-14 04:29.


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