A University of Texas at
Arlington physicist working to create a luminescent nanoparticle to use in
security-related radiation detection may have instead happened upon an advance
in photodynamic cancer therapy.
Wei Chen, professor of physics
and co-director of UT Arlington’s Center for Security Advances Via Applied
Nanotechnology, was testing a copper-cysteamine complex created in his lab when
he discovered unexplained decreases in its luminescence, or light emitting
power, over a time-lapse exposure to X-rays. Looking further, he found that the
nanoparticles, called Cu-Cy, were losing energy as they emitted singlet oxygen
– a toxic byproduct that is used to damage cancer cells in photodynamic
Because Chen also is leading
federally funded cancer research, he knew he had found something unique.
Testing revealed that the Cu-Cy nanoparticles, combined with X-ray exposure,
significantly slowed tumor growth in lab studies.
“This new idea is simpler and
better than previous photodynamic therapy methods. You don’t need as many
steps. This material alone can do the job,” Chen said. “It is the most
promising thing we have found in these cancer studies and we’ve been looking at
this for a long time.”
Chen’s research is being
published in the August edition of the Journal of Biomedical Nanotechnology
under the title “A New X-Ray Activated Nanoparticle Photosensitizer for Cancer
Treatment.” Co-authors are Lun Ma, a research assistant professor, and Xiaoju
Zou, a research associate. The paper is available online at http://www.aspbs.com/JBN/contents_jbn2014108.htm.
The University has also filed a
provisional patent application on the new complex.
Photodynamic therapy, or PDT,
harms cancer cells when a photosensitizer introduced into tumor tissue produces
toxic singlet oxygen after being exposed to light. In some studies, this light
exposure is done through use of visible or near-infrared lasers. Others have
found more success by also introducing luminescent nanoparticles into the
tumor. Researchers activate the luminescent nanoparticle with near-infrared
light or X-rays, which in turn activates the photosensitizer.
methods have limitations for treating deep tissue cancers. They are either
inefficient or the light source needed to activate them doesn’t penetrate deep
enough. Chen said that X-ray inducible Cu-Cy particles surpass current
photosensitizers because the X-rays can penetrate deep into tissue. Also, Cu-Cy
nanoparticles don’t need other photosensitizes to be effective so the treatment
is more convenient, efficient and cost-effective.
“Dr. Chen’s commitment to his work in cancer-related therapy, as well
as his work in the area of homeland security, demonstrates the wide-ranging
applications and great value of basic science research,” said Carolyn Cason,
vice president for research at UT Arlington. “These advances have the potential
to change the way some cancers are treated and make therapy more effective – a
benefit that would be boundless.”
Chen’s team tested the Cu-Cy on
human breast and prostate cancer cells in the lab and found it to be an
effective treatment when combined with X-ray exposure. In one test, for
example, a tumor treated with Cu-Cy injection and X-ray exposure stayed virtually
the same size over a 13-day period while a tumor without the full treatment
grew by three times.
Ma said: "Photodynamic therapy is limited to treat superficial
diseases such as skin cancer because current photosensitizers cannot be
activated using high energy irradiations that are able to deeply
penetrate into tissues. As a new photosensitizer, the Cu-Cy can be
effectively activated by X-ray irradiation for cancer cell destruction.
It may be a breakthrough to bring photodynamic therapy to deep cancer
Another advantage of the new
nanoparticle is a low toxicity to healthy cells. In addition, Cu-Cy’s intense
photoluminescence and X-ray luminescence can be used for cell imaging, the
Details of the crystal structure
and optical properties of the new complex are being published in an upcoming
paper from the Journal of Materials Chemistry. It is available here: http://pubs.rsc.org/en/content/articlepdf/2014/tc/c4tc00114a.
The UT Arlington team continues to pursue
photodynamic cancer therapy research under a grant from the Department of
Defense Congressionally Directed Medical Research Programs and with collaborations
from industry. Further research will include reducing the size of the
Cu-Cy nanoparticle to make it more easily absorbed in the tumor tissue.
“For cancer, there is still no
good solution yet. Hopefully this nanoparticle can provide some possibilities,” Chen said.
About UT Arlington
The University of Texas at Arlington is a comprehensive research
institution and the second largest institution in The University of Texas
System. The Chronicle of Higher Education ranked UT Arlington as the
seventh fastest-growing public research university in 2013. U.S. News &
World Report ranks UT Arlington fifth in the nation for undergraduate
diversity. Visit www.uta.edu to learn more.