Recently, an international team of researchers from Tel Aviv University in Israel, the Hebrew University in Jerusalem and the University of Newcastle in the United Kingdom has developed a film containing carbon nanotubes and nanorods that could be used as a wireless implant to induce photostimulation in the retina. Related papers were published in the recent nano express.
Light shining on the retina behind the eye is the first step in the visual process, according to a recent report on the Physicist Network. If the macular degeneration causes the photoreceptors on the retina to degenerate, the retina will no longer respond to light, causing the patient to lose all vision. But if the retina can be sensitized again with the help of a photoelectric implant, the patient may regain vision.
At present, the development of artificial retina is still facing many challenges: implantation equipment to be able to long-term photosensitivity, have a high spatial resolution, without wires, can adapt to the body without rejection, but also a certain degree of mechanical flexibility. Candidates for artificial retina include conductive polymers and quantum dot films, but each has its advantages and disadvantages in meeting these requirements. Another way is to restore the photosensitivity of the retina by inserting photoreceptor proteins (bacterial visual proteins) into retinal neurons using photogenic techniques. But this method still needs electrodes to assist neurons in light induced stimulation.
In the membrane structure, nanorods are dispersed in the whole three-dimensional matrix of porous nanotubes, and finally a flexible matrix layer suitable for implantation is formed. Researchers point out that the new material has many advantages, such as high light absorption, tight binding with neurons, and high efficiency in conducting electricity. Other candidate materials for artificial retina, such as silicon, are hard and opaque, and require external power, but the new material does not have these problems. With these advantages, the new membrane will have a bright future in the application of artificial retina in the future.
"The greatest significance of this work is to show how new materials (quantum rods combined with carbon nanotubes) form a new system that effectively stimulates the nervous system." Iyer Hanetn, a co-author of the thesis, said Professor Iyer Hanetn.
The researchers attached the membrane to the retina of a 14-day-old chick, which is completely blind and has no photoreceptor, and the retina produces a photoelectric current, a neural signal that can be interpreted and processed by the brain.
The researchers also hope to continue to improve it in future research. "At present, we are studying this new implant in vivo, hoping to observe its performance in long-term applications." "We're working with retinal surgeons to develop this implant and test its compatibility with conventional surgery, with the goal of making it available for clinical use in humans in the future," Hahn said.