AsianScientist (July 5, 2017) – Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) have developed a novel photosensitizer that uses the amino acid taurine to make brain cancer treatments more effective. Their research has been published in Chemical Communications.
During photodynamic therapy, a drug called a photosensitizer is injected into the patient’s bloodstream where it preferentially accumulates in cancer cells. When exposed to light, the photosensitizer emits reactive oxygen species (ROS) that kills the cancer cells. Because photodynamic therapy reduces the damage inflicted on healthy cells, it is a more specific way to treat brain and other tumors.
This method is far from perfect, however. Although the polypyridyl Ruthenium (Ru)-complexes that make up the photosensitizer are stable, biocompatible and highly efficient in emitting ROS, their bulky chemistry makes them insoluble in water. This impedes the dispersal of photosensitizer through the blood which is over 90 percent water.
To solve this problem, the OIST research team added the natural amino acid taurine into chemical makeup of the Ru-complex to create a new type of photosensitizer. Taurine is one of most abundant amino acids in the central nervous system and assists with essential brain functions such as the transmission of signals. It is also biocompatible and naturally soluble in water.
“Taurine-modification is pretty simple,” said Professor Zhang Ye from the Bioinspired Soft Matter Unit who co-authored the paper with Dr. Du Enming.
Notably, the OIST researchers found that the taurine-modified Ru-complexes were able to enter cells effectively while retaining their ROS-dependent cell killing activity. In addition, they observed that the modified complexes were particularly effective at destroying brain cancer cells, as opposed to other types of cancer cells.
For years, researchers have been exploring different chemical components to create an effective photosensitizer for photodynamic therapy, yet no one method has yielded optimal results. The taurine-modified photosensitizer created by the OIST research team is a promising new avenue of exploration. With further modification, it could pave the way for better brain cancer treatment using photodynamic therapy.
The article can be found at: Du et al. (2017) Taurine-modified Ru(II)-complex Targets Cancerous Brain Cells for Photodynamic Therapy.
Source: Okinawa Institute of Science and Technology Graduate University.
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