KAIST: "OLED 'Red Light' Shows Improvement in Alzheimer's"

A study has found that it is possible to achieve improvement in the treatment process for Alzheimer's disease using only OLED light, without any medication. Based on this, there is potential to precisely control the color, brightness, flicker ratio, and exposure time of OLED light, enabling the development of personalized OLED "electroceuticals."

(From top) Research team led by Professor Kyungchul Choi at KAIST, research team led by Dr. Jaewook Koo at the Korea Brain Research Institute, research team led by Dr. Hyangsook Heo at the Korea Brain Research Institute members. Provided by KAIST

KAIST announced on November 24 that a research team led by Professor Kyungchul Choi from the Department of Electrical Engineering at KAIST, along with research teams led by Dr. Jaewook Koo and Dr. Hyangsook Heo at the Korea Brain Research Institute (KBRI), have developed a three-color OLED photostimulation technology with uniform luminance. They confirmed that among blue, green, and red, "red 40Hz light" most effectively improves Alzheimer's pathology and memory function.

The joint research team established an OLED-based photostimulation platform that emits light uniformly, addressing structural limitations of existing LED methods, such as brightness imbalance, heat generation risk, and stimulation variation due to animal movement. They compared white, red, green, and blue light under identical conditions (40Hz frequency, brightness, exposure time) and found that "red 40Hz" light produced the most significant improvement in memory function.

Notably, in early-stage (3-month-old) animal models, just two days of stimulation led to improvements in both pathology and memory.

When early-stage Alzheimer's animal models were exposed to light for one hour per day over two days, both white and red light improved long-term memory. In addition, the amount of amyloid beta (Aβ) plaques-protein aggregates known as a key cause of Alzheimer's disease-accumulated in critical brain regions such as the hippocampus was reduced.

The experiments also confirmed a significant increase in the enzyme ADAM17, which helps remove plaques.

This suggests that even short-term light stimulation can reduce harmful proteins in the brain and improve memory function.

Most importantly, under red light, the inflammatory cytokine IL-1β-which can worsen inflammation or stress brain tissue and influence the progression of Alzheimer's disease-was significantly reduced, confirming an anti-inflammatory effect.

The joint research team also verified through experiments that the greater the reduction in plaques, the greater the improvement in memory, demonstrating a direct link between pathological improvement and cognitive function enhancement.

In mid-stage (6-month-old) models, statistically significant pathological improvement was observed only with red light. When mid-stage Alzheimer's models received long-term stimulation under the same conditions for two weeks, both white and red light improved memory, but a statistically significant reduction in plaques was observed only with red light.

At the molecular level, color-specific differences were clear. When exposed to red light, the enzyme ADAM17, which helps remove plaques, increased, while the enzyme BACE1, which contributes to plaque formation, decreased, demonstrating a "dual effect" of inhibiting plaque formation and promoting removal.

In contrast, white light only reduced the enzyme BACE1, making its therapeutic effect more limited than that of red light. This scientifically demonstrates that the color of light is a key factor in determining treatment efficacy.

Schematic diagram of the mechanism by which red OLED stimulates nerve cells to reduce amyloid beta in Alzheimer's experimental mice. Provided by KAIST

To determine which brain circuits were activated after light stimulation, the joint research team analyzed the expression of the marker gene c-Fos, which is the first to turn on when brain cells are activated.

This revealed that the entire "visual-memory circuit"-from the visual cortex to the thalamus to the hippocampus-was activated, providing neurological evidence that light stimulation awakens the visual pathway, leading to enhanced hippocampal function and memory.

The uniform luminance OLED platform also ensured that light was evenly delivered even when the animals moved, resulting in consistent experimental outcomes. The effects were reproducible in repeated experiments, confirming the reliability of the results, according to the joint research team.

This study is significant in that it is the first to demonstrate that cognitive function can be improved using only light, without medication, and that Alzheimer's pathological indicators can be modulated by combining color, frequency, and duration.

The OLED platform developed by the joint research team can precisely control color, brightness, flicker ratio, and exposure time, making it suitable for designing personalized stimulation protocols for human subjects.

Accordingly, the joint research team plans to expand the research to the clinical stage by exploring various conditions such as stimulation intensity, energy, duration, and combined visual and auditory stimulation.

Professor Choi stated, "The uniform luminance OLED platform overcomes the structural limitations of conventional LEDs, enabling high reproducibility and safety assessment. The joint research team expects that wearable 'RED OLED electroceuticals' for daily therapeutic use will present a new paradigm for Alzheimer's treatment."

This research was supported by the National Research Foundation of Korea, the National Information Industry Promotion Agency, and the basic research program of the Korea Brain Research Institute.

The research results (paper) were recently published online in the international journal 'ACS Biomaterials Science & Engineering,' which specializes in biomedical and materials science.

This content was produced with the assistance of AI translation services.