Nanoparticles with X-rays can kill cancer cells deep within the living body

Melbourne: Nanoparticles used in combination with X-rays are a viable method for killing cancer cells deep within the living body, a new study has found.

The findings by researchers from the Centre for Nanoscale BioPhotonics (CNBP) in Australia are based on the successful quantification of singlet oxygen produced during photodynamic therapy for cancer.

Singlet oxygen molecules (a highly reactive form of oxygen) are able to kill or inhibit growth of cancer cells in the body due to their toxicity.

"Photodynamic therapy is where light sensitive compounds are placed near diseased cells, then activated by light, producing short lived molecular by-products that can destroy or damage the cells being targeted," said Ewa Goldys from CNBP.

"In this case, X-rays (a form of light) were used to stimulate cerium fluoride (CeF3) nanoparticles which had been placed near a group of cells. Singlet oxygen was produced as a by-product of the X-ray and CeF3 interaction, which was then successfully measured," she added.

The findings are significant as this is the first time that anyone has been able to quantify accurately, the number of singlet oxygen molecules produced in this type of procedure, researchers said.

"Singlet oxygen molecules are a far more reactive form of oxygen but they can only kill cancer cells if generated in sufficient quantity," said Ms Goldys.

"In our testing we established that therapeutic radiation dose X-rays, produce enough singlet oxygen molecules to be effective in photodynamic therapy," she said.

Photodynamic therapy has traditionally utilised near-infrared or visible light which has been unable to penetrate far into the body, limiting its use to cancer treatment, on or near the surface of the skin, Ms Goldys said.

The treatment uses different biological pathways to kill cells as compared to chemotherapy, radiotherapy and other current cancer practices.

"We are looking to target cancer cells deeper in the body hence the use of X-rays, which can really penetrate into deeper levels of tissue, and are already used in medical diagnostic and therapy," Ms Goldys said.

"What we have shown through our measurements is the applicability of the photodynamic therapy approach to effectively treat tumours within," she said.

Deep tissue photodynamic therapy will potentially provide new treatment options for the cancer patients of the future, researchers said.

The findings were published in the journal Scientific Reports.