Scientists have successfully tested ultrathin retinal prosthesis on mice.
South Korean researchers from Yonsei University in Seoul have developed an artificial retina that could revolutionize vision restoration. In a paper published in the science journal Nature Nanotechnology, the team under Won Gi Chung from the Department of Materials Science & Engineering at Yonsei explains the benefit of the novel retina: Common electronic retinal prostheses, or bionic eyes, are inflexible and their rigid electrodes can inflict damage to soft tissue around the retina. The novel artificial retina is made of softer material, and inflexible electrodes are replaced by integrating phototransistors with three-dimensional liquid metal microelectrodes made of a eutectic gallium-indium alloy. Eutectic means that the alloy has a lower melting point than its constituents. Gallium has a melting point of 29,76 °C, while indium’s is at 156,6 °C. The alloy has a melting point of around 15.7 °C.
The researchers explain that the combination of softer material and the liquid nature of the microelectrodes prevents possible damage to surrounding tissue. In addition, the electrodes are locally coated with platinum, which aids in injecting charges into the retinal neurons, enhancing the electrodes’ transmission properties to the retinal neurons.
Because of the liquid state of the gallium-indium alloy, the artificial retina is rinsed and frozen to solidify before implantation. The device is then implanted into the retina of mice for testing. The team tested the retina successfully more than ten times, and the researchers hope to expand the experiment to a larger scale. However, to help humans suffering from vision loss, the retina will have to be enhanced significantly, as the picture in the experiment was limited to 36 pixels due to the small size of the mouse eye. In comparison, despite humans nor mice seeing in pixels, human eyesight is estimated to be 576 million pixels.
Technology Metals Boost Scientific Breakthroughs
The low melting point of gallium is one of the metal’s core benefits to comparable elements and is one of the reasons the metal has grabbed the attention of researchers trying to enhance technologies. For example, injections and blood sampling could be facilitated using needles that soften when injected. However, gallium’s low melting point is not its only asset. An American startup utilizes gallium nitride semiconductor’s superior efficiency in transmitting currents compared to silicon-based versions to de-frost airplane wings, which could help prevent delays at airports in the future.
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