Microwaves and nanoparticles combined to generate 'lethal bullet' in cancer

The use of photodynamic therapy (PDT) in cancer treatment has been hampered by the limited penetration of light to the target tumor. Now a research team has shown that photosensitizers can be activated by microwaves which can reach deeper tumors. The results may lead to improved cancer treatment. 

The team, led by Wei Chen, a professor of physics at the University of Texas at Arlington, published their results in the Journal of Biomedical Nanotechnology.

"Our new method using microwaves can propagate through all types of tissues and target deeply situated tumors," said Chen in a release

PDT has previously relied on visible, UV or infrared light for its therapeutic gain. However, light at these wavelengths is unable to reach deep tissue, so targeting tumors with them has remained problematic. Chen and colleagues set about to change this. With harnessed nanoparticles activated by microwaves, they were able to use a wavelength that can travel deeper into the tissue--activating a "lethal bullet" in the tumor.

They used a nanoparticle of copper-cysteamine (Cu-Cy) that on activation by microwaves produce a singlet oxygen, enough to generate reactive oxygen species in the tumor and effectively kill the cell. In previous studies, Cu-Cy had been activated by X-rays, but the radiation from X-rays meant researchers had to seek an alternative approach.

In comparison, microwaves can target the tumor cells directly without harming the surrounding tissue. Moreover, the nanoparticle Cu-Cy has very low toxicity, it is cheap and easy to produce and also gives off an intense luminescence, meaning it doubles as an imaging agent.

"Dr. Chen's research into nanoparticle activation has led to important discoveries that could potentially transform cancer treatment," said Alex Weiss, head of the physics department at the university, in the statement. "This new paper on the possibilities of microwave activation demonstrates yet again how Dr. Chen's search for new modalities of therapy could play a key role in finding safe, viable and inexpensive treatments for cancer."