Professor Chan Beum Park and his research team from the Department of Materials Science and Engineering here at KAIST collaborated with Dr. Kweon Yu from the Neurophysiology Research Group in the Bionano Center at the Korea Research Institute of Bioscience and Biotechnology (KRIBB) in using light and porphyrins to suppress aggregation of β-amyloid, the main factor that causes Alzheimer's disease. This novel finding can potentially open new possibilities for curing many other neurodegenerative diseases including Alzheimer's disease. The research was titled “Photoexcited Porphyrins as a Strong Suppressor of β-Amyloid Aggregation and Synaptic Toxicity” and published on the German journal, Angewandte Chemie.

Alzheimer's disease is a progressive neurodegenerative disease caused by the aggregation of a protein called β-amyloid that makes plaques in the brain. As a result, extracellular amyloid plaques and intracellular neurofibrillary tangles are the hallmarks of Alzheimer’s. These plaques harm the brain cells and lead to loss of brain functionality.

Curing this neurodegenerative disorder using light, namely photodynamic therapy, has the advantage of allowing temporal and spatial manageability of the treatment and reducing side effects. Despite the fact that the use of organic photosensitizers in photodynamic therapy has many merits, it has not been frequently used in curing neurodegenerative diseases.

The research team effectively suppressed the aggregation of β-amyloid by using porphyrin molecules and blue light illumination. It was important to suppress the aggregation of β-amyloid in order to block the formation of plaques in the brain to prevent or relieve Alzheimer’s. Suppression of β-amyloid aggregation occurs when photosensitizer porphyrin produces reactive oxygen that absorbs light energy after the transition from excited state to ground state. Newly generated reactive oxygen oxidizes the β-amyloid monomer, which interferes with β-amyloid aggregation. The research team applied this principle to the drosophila Alzheimer's disease model and discovered that porphyrin alleviates neural cell death, synaptic toxicity, and behavioral defects.

Professor Park said, "It was very meaningful to verify for the first time that usage of light and photosensitizer in drosophila actually suppressed β-amyloid aggregation and alleviated toxicity."