As the silicon glass becomes the base material for making optical fiber, silicon has become the main material in the field of inorganic photoelectric equipment. Not only is it easy to get, but from a material point of view, the way it works is simple. But in the field of organic optoelectronics, scientists need to find a material that has the same advantages, and it's best to live in the world of life.
The material we're going to introduce today is DNA. It can be used to make waveguides like silicon fibers that transmit light in the body. In the future, these organic devices will be easier to make, more flexible than silicon, and more environmentally sound.
Recently, researchers at Yonsei university in Seoul, South Korea, wanted to make organic membranes from the DNA of salmon.
The membrane is usually used for cancer treatment and health monitoring, it not only has the function of all silicon base equipment, but also has the advantage of more compatibility with living tissue, which can be made into better medical electronic equipment and photonics equipment.
As the name suggests, the film is just a layer of optical materials
with nanometers or microns thick to guide the light. If the membrane is insulative, that is to say, insulators like glass, we don't have to worry about it conducting electricity when used.
In optical equipment, one of the key properties of the material is the refractive index, which determines the direction of light transmission. The optical fiber needs the fiber core with the same refractive index and the coating of different refractive index. So when the light hits the core and the cladding interface, it is forced to return to the core instead of leaking out. The manufacturer of the optical fiber needs not only the material with two different refractive index, but also the order of magnitude of the difference to obtain the desired effect.
In the fine-tuning method, which uses DNA to make films that can be used in optical devices, Oh's team can achieve a refractive index that is four times higher than silicon. With a higher refractive index difference between the core and the cladding, they can make thinner fibers, compared to the 10 microns that use silicon, and they are as low as 3 microns in diameter. For the light that comes out of the fiber, it brings a smaller speckle size, so it can be used for applications that require more careful targeting of light.
The potential applications of this membrane include photodynamic therapy, with this treatment, cancer patients receive drugs or other substances that bind to cancer cells in the tumor, use light to activate drugs and kill cancer cells, without harming healthy tissue.
The membrane can also be used in optogenetics, which can be used to control specific brain cell activity, or make sensors that measure blood pressure or oxygen levels, and wear them for long periods of time without causing allergies, because they are organic.
The membrane can be used for temperature sensors, and the changes in light through the membrane are associated with temperature changes. Oh's lab is also expanding other options for controlling the optical properties of DNA. He hopes to develop a range of basic features and processes that will allow manufacturers to make a variety of optical devices, including a new generation of wearable sensors.