Wei Chen, a physics professor at University of Texas at Arlington, knows first-hand that some of the best inventions are born through chance observations in the laboratory. While working with copper-cystamine nanoparticles (Cu-Cy) on a security-related radiation detection project, Dr. Chen noticed that the complexes lost their bright pink luminescence [which results from their crystal structure] when exposed to X-rays over time. He explored further and found the Cu-Cy were losing energy through singlet oxygen emission.
Singlet oxygen is a toxic byproduct used to damage cancer cells during photodynamic therapy (PDT): a photosensitizer is introduced into tumor tissue and exposed to visible or near-infrared lasers light, causing the photosensitizer to release singlet oxygen. The downside to this treatment is that an external light source has difficulty penetrating through thick tissue and inefficiently activates the photosensitizers. Since Dr. Chen is also federally funded for cancer research, he was knowledgeable of PDT. When he made his discovery, he knew he had found something unique. “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,” said Dr. Chen in a news release. Cu-Cy emit singlet oxygen when excited by X-rays, which can penetrate much deeper than visible light. Additionally, they are not toxic to healthy cells.
Two professors at UT Arlington, Lun Ma and Xiaoju Zou, exemplified the utility of Dr. Chen’s Cu-Cy for cancer treatment in a study published online ahead of print by Journal of Biomedical Nanotechnology. They conducted in vitro and in vivo tests on human breast cancer cells and found that tumors treated with Cu-Cy and X-rays remained unchanged 13 days after exposure, compared to unexposed tumors that tripled in size. The authors concluded that Cu-Cy are potent photosensitizers and can be used for deep cancer treatment. The university has filed a provisional patent for Cu-Cy. “It is the most promising thing we have found in these cancer studies and we’ve been looking at this for a long time,” said Dr. Chen.
The versatility of Dr. Chen’s work does not go unnoticed: “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.” Future endeavors will include reducing the size of Cu-Cy to allow for more absorption in tumor tissue. Dr. Chen is optimistic about the future of these nanoparticles and stated, “For cancer, there is still no good solution yet. Hopefully this nanoparticle can provide some possibilities.” He is able to pursue this work under a grant from the Department of Defense Congressionally Directed Medical Research Programs and with industry collaborations.