Study Identifies How Squid Have Evolved to See in Dim Ocean Water

In a new paper published in Science, research led by postdoctoral fellow Jing Cai and Alison Sweeney, an assistant professor of Physics and Astronomy, provided a detailed look into how self-assembled squid lenses have evolved to adjust for light distortion, which allows them to see clearly in the dim waters of the open ocean.

In addition to contributing to the field of nanotechnology by outlining self-assembly at the nanometer length scale, the research could one day help scientists build improved artificial lenses that can focus light perfectly. It could also allow them to better understand cataracts, a clouding of the human eye lens that leads to blurred vision.​​​​​​​​​​​​​​

“In biology,” Sweeney says, “you're dealing with proteins, DNA and RNA, not Lego bricks. Our analog for Lego bricks in this study was the individual proteins that make up the refractive material in the lens. We found that squid have a really elegant optical design whereby having a very dense material in the center, made of proteins with lots of linkage sites, and a very sparse material on the edge, made of proteins with two linkage sites, they can form a spherical lens that doesn't suffer from spherical aberration. This work was a really nice case study that enabled us to talk about the evolution of self-assembly, or how evolution invents new materials through a random process, in detail, without needing to be speculative about it.”

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