A
new study has shown that adding boron-nitride nanotubes to the surface of
cancer cells can double the effectiveness of Irreversible Electroporation, a
minimally invasive treatment for soft tissue tumors in the liver, lung,
prostate, head and neck, kidney and pancreas. Although this research is in the
very early stages, it could one day lead to better therapies for cancer.
The study was carried out by researchers in Italy at
the Institute of Life Sciences, Scuola Superiore Sant'Anna in Pisa with BNNTs
provided by researchers at NASA's Langley Research Center, the Department of
Energy's Thomas Jefferson National Accelerator Facility and the National
Institute of Aerospace.
Irreversible Electroporation is a new therapy for
difficult-to-treat cancers in soft tissues. It is offered in many cancer
treatment centers across the United States, and is being studied for effectiveness
on a wide variety of specific cancers. Researchers at the Institute of Life
Sciences began experimenting with BNNTs to see if the nanotubes could make the
treatment more effective.
"Irreversible Electroporation is a way of
putting holes in the wall of a tumor cell," said Michael W. Smith, chief
scientist at BNNT, LLC and formerly a staff scientist at NASA's Langley
Research Center.
Smith explained that when a hole of proper size is
made in the wall of a cell, the cell reacts in a predictable fashion. Although
the exact mechanism has not been pinpointed, researchers suspect that such a
hole could trigger cell suicide. "The cell will literally go, Oh,
something's terribly wrong, and kill itself. That's called apoptosis," he
added.
Smith read about the Italian researcher's trials
with BNNTs in a journal, and he offered the researchers a sample of the very
high-quality Jefferson Lab/NASA Langley/NIA BNNTs. These BNNTs are highly
crystalline and have a small diameter. Structurally, they also contain few
walls with minimal defects, and are very long and highly flexible.
The Italian researchers first suspended the BNNTs in
glycol-chitosan, a type of bio-soap solution, and blasted the tubes with sound
waves to chop them into smaller bits. The solution, containing varying amounts
of BNNTs, was then dumped on clusters of human epithelial carcinoma cells (also
known as HeLa cells) in the lab to see if the BNNTs alone would kill the cells.
The researchers determined the amount of BNNTs that killed roughly 25 percent
of the cancer cells over 24 hours.
The researchers then exposed the HeLa cells to that
amount of BNNTs in solution and zapped the cells with 160 Volts of electricity,
which was the electroporation device supplier's suggested voltage and
corresponds to an electric field of 800 Volts per centimeter. The researchers
also treated unexposed cancer cells with the same voltage.
They found that the Irreversible Electroporation
treatment method killed twice as many cancer cells with BNNTs (88 percent) on
the cell surface than without (40 percent).
"They were able to get, in a petri dish, more
than double the effectiveness. So, this technique works twice as well with our
nanotubes on the cells than without them. That's a big deal, because you can
either use a lot less voltage or kill a lot more cells," said Smith.
Smith and his colleague, Kevin Jordan, a Jefferson
Lab staff engineer and chief engineer at BNNT, LLC, said that BNNTs have a long
list of potential uses.
"Technology researchers say these nanotubes
have energy applications, medical applications and aerospace
applications," said Jordan.
The researchers are now attempting to scale up the
production process, while also improving the purity of the BNNTs. Their aim is
to be able to produce mass quantities of tubes for exploration of the full
gamut of potential applications.
For instance, the Italian researchers will need more
high-quality BNNTs to continue their studies in mice. Moving to this next step
is promising, but the research is still in the very early stages, and it still
has a long way to progress before the technique will be considered for use in
the clinic to treat cancer.
Researchers at NASA's Langley Research Center, the
Department of Energy's Thomas Jefferson National Accelerator Facility and the
National Institute of Aerospace created a new technique to synthesize
high-quality boron-nitride nanotubes (BNNTs).
The pressurized vapor/condenser (PVC) method was
developed with Jefferson Lab's Free-Electron Laser and was later perfected
using a commercial welding laser. In this technique, the laser beam strikes a
target inside a chamber filled with nitrogen gas. The beam vaporizes the
target, forming a plume of boron gas.
A condenser, a cooled metal wire, is inserted into
the boron plume. The condenser cools the boron vapor as it passes by, causing
liquid boron droplets to form. These droplets combine with the nitrogen to
self-assemble into BNNTs.
ScienceDaily
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