Colleen Alexander prepares cancerous cells that could soon be treated with drug-bearing nanoparticles invented in the Syracuse University laboratory of James Dabrowiak. Photo: Syracuse University |
About
every three days, Colleen Alexander, a chemistry graduate student,
feeds cells that cause a deadly type of brain cancer. It’s a ritual that
involves assessing the health of the cells under a microscope, washing
away dead cells with a special solution, and instilling clean medium that
will nurture the living cells and generate new ones. At some point,
these cells will be subjected to chemotherapy agents attached to
nanoparticles made of gold.
It’s
a revolutionary idea for a molecular drug delivery system developed by
two chemists in Syracuse University’s College of Arts and Sciences who
have combined their very different areas of expertise. Their work was
recently featured in the Journal of the National Cancer Institute (NCI)
in a news article that highlights the NCI’s increasing focus on using
nanotechnology to diagnose and treat cancer. It’s an area of research in
which the NCI is investing $30 million per year, nationally, over the
next five years.
The
idea for attaching chemotherapy drug molecules to nanoparticles made of
gold developed from a series of hallway conversations and “what ifs”
between James Dabrowiak and Mathew Maye. Both are members of the
college’s Department of Chemistry and of the Syracuse Biomaterials
Institute, which provides highly specialized laboratory facilities for
their work.
Dabrowiak
has devoted the better part of his career to cancer drug research and
is Alexander’s PhD faculty adviser. Maye’s expertise lies in
nanotechnology. He uses biomimetic methods to assemble nanomaterials.
Biomimetic means using DNA to make nanoparticles mimic nature.
“You
can put an enormous amount of small drug molecules onto a single
nanoparticle,” Dabrowiak says. “That results in very high concentrations
of the drug getting into cancer cells, making the drug a more effective
killing agent with fewer side effects.”
The
trick is in finding the most effective way to build the drug-laden
nanoparticles. That’s where Maye’s expertise comes in. His laboratory has
developed a way to attach DNA to gold nanoparticles. The drug molecules
stick to the DNA-coated nanoparticles, coded to attract specific types
of drugs. Once the drug is attached, the surface of the nanoparticle is
coated with inert materials to prevent the immune system from attacking
the nanoparticle as a foreign invader before it makes its way to the
tumor.
“Ours
is a completely different way of designing a molecular drug delivery
system,” Maye says. “The method we use to attach drug molecules to the
DNA is a unique part of the system. It’s an area of research that no one
is exploring.”
In
addition to delivering a higher concentration of drugs to individual
cancer cells, the scientists say nanoparticles could potentially be more
efficient at getting inside tumors than current drug delivery systems.
Because of their rapid growth, tumors are less densely packed and more
porous than healthy tissues. Drug molecules are small and tend to leak
out of the pores, reducing the drug’s effect on the tumor. In contrast,
the larger nanoparticles tend to get stuck inside the pores, allowing
the drug more time to penetrate the tumor.
“The
nanoparticles are more easily caught by tumors than by normal tissue,”
Dabrowiak says. “More drug gets inside tumors and less gets inside
healthy tissue, which leads to fewer side effects for patients.”
The
scientists’ ultimate goal is to develop “smart nanoparticles” that
would only seek out cancer cells, leaving healthy cells and tissue
untouched. “We can attach several kinds of molecules to a single
nanoparticle, including particles that recognize specific features of
cancer cells,” Maye says. “Our goal is to develop smart nanoparticle
delivery systems for existing chemotherapy drugs.”
