Researchers enhance cancer-fighting radiation therapy with iodine nanoparticles

One of the most researched diseases scientists around the world are fighting to cure is cancer. Recently, researchers discovered a way to enhance radiation therapy using novel iodine nanoparticles. The team says cancer cell death is triggered within three days when x-rays are shined onto tumor tissue containing iodine-carrying nanoparticles. The iodine releases electrons that break the tumor's DNA, leading to cell death.

The findings were announced by scientists from Kyoto University's Institute for Integrated Cell-Material Sciences working with colleagues in Japan and the US. Project researchers say that exposing the metal to light leads to the release of electrons, which is called the photoelectric effect. Einstein explained that phenomenon in 1905, ushering in the birth of quantum physics. This new research provides evidence suggesting that it's possible to reproduce that effect inside cancer cells.

One of the biggest challenges with radiation therapy for treating cancer today is that it's ineffective in the center of tumors, where oxygen levels are low due to the lack of blood vessels. X-ray radiation requires oxygen to generate DNA-damaging reactive oxygen when the rays hit molecules inside the cells. Researchers have been trying to overcome the issue by discovering direct ways to damage cancer DNA. Earlier work showed that gadolinium-loaded nanoparticles could kill cancer cells when irradiated with 50.25 kilo electron volts of synchrotron-generated x-rays.

For the new study, scientists designed porous iodine-carrying organosilica nanoparticles. They note that iodine is cheaper than gadolinium and releases electrons at lower energy levels. The nanoparticles were dispersed through tumor spheroids, which are 3D tissue containing multiple cancer cells. After irradiating the spheroids for 30 minutes with 33.2 keV of x-rays, the cancer cells completely died within three days.

The team was able to show through systematically changing energy levels that optimum tumor destruction occurred with 33.2 keV X-ray. Researchers say the study represents an important example of employing a quantum physics phenomenon inside cancer cells.