Japan develops new flexible MicroLED array film
Supported by the Strategic Creation and Research Promotion Division of Japan Science and Technology Agency (JST), Japan Dokyo Medical University, Toyohashi University of Technology, and Okinawa Institute of Science and Technology University jointly developed a flexible multi-point Micro LED array medical film. It can flexibly adhere to specific areas of the brain for light irradiation, and is expected to comprehensively analyze the causal relationship between neural activity hidden in brain information, behavior, and diseases, and has broad application prospects in the field of optogenetics.
According to the JST official website, the Japanese scientific research team has successfully achieved the control of nerve cell activity by irradiating light from outside the organism through in-depth research in recent years, using optogenetics methods. For this reason, the element for light irradiation becomes the key. Through this embedded component, the target nerve cells can be freely manipulated with light. However, there is no replacement for embedded optics that cover the entire cerebral cortex.
For this reason, in order to realize light, thin, and flexible embedded components, it is necessary to establish a technology to achieve high-precision configuration on an extremely thin biocompatible film in an LED layer with a thickness of several μm. The research team has successfully developed a high-density, high-definition Micro LED hollow structure formation technology, and established a high-precision unified transfer technology through the application of thermal peeling sheets, forming a thin and light structure that does not reduce light performance even if it is bent The multi-point Micro LED array ultra-thin film.
At present, the scientific research team is trying to study the use of light to control the activity of various functional molecules in living organisms. Among them, optogenetic methods use light to control neural activity by expressing light-sensing proteins in nerve cells that respond to specific colors of light. This method has high temporal resolution and has been used to understand brain function. In order to fully understand the complex brain neural network formed by nerve cells, researchers have been studying light stimulation techniques that can freely control specific nerve cell sites that are widely distributed in the brain. However, using traditional fiber optics and microscopy methods, it is difficult to illuminate a specific site or multiple sites at the same time, and studies in freely moving animals are limited. Therefore, high expectations are placed on the embedded LED components.
However, the size of the LEDs sold in the market is usually 200 μm, and the thickness is also tens of μm to 100 μm. The larger size is not suitable for covering the entire brain, and it is not suitable for light stimulation of a specific nerve cell component equipment use.
The research team aimed at thin, light, and bendable flexible films, and on this basis, tried extremely small Micro LED arrays with a size of less than 100 μm and a thickness of several μm. To this end, the Micro LED thin film was prepared by anisotropic wet etching method, which selectively removes the bottom LED layer by potassium hydroxide, thereby forming a very densely arranged Micro LED hollow structure. Since the hollow structure separates the LED layer and the substrate, the LED layer can be peeled off at one time by a thermal release sheet (transfer technique) without damaging the Micro LED or biocompatible parylene film.
The overall size of the flexible Micro LED film is less than 100 nanometers and the thickness is a few nanometers. Even in the case of bending, the Micro LED will not deteriorate the illumination characteristics and can still maintain the same performance. In addition, when the researchers covered the surface of the mouse brain with a flexible Micro LED film, they also obtained bright blue light and used it in practical optogenetic experiments.
The multi-point Micro LED film developed by the Japanese R&D team that can be widely used in the brain realizes the free control of complex brain activities in space and time through light. Various regions of the brain have different functions and complex control of whole-body activity. In the future, it is expected that by combining with measurement technology, new neuroscience research will be developed with the goal of comprehensively understanding brain activity, behavior, and disease based on causality. In addition, through further research on photosensitive biofunctional molecules, depending on light irradiation, it is expected that the locking site can function for a set time, and the phototherapy technology using embedded elements is also expected to be widely used.