Unpicking Nature’s Invisibility Cloak

Cephalopods are highly intelligent marine creatures. This group within the molluscan class Cephalopoda includes octopus, squid, cuttlefish, and nautilus. These animals are characterized by a prominent head and a set of tentacles, but a less obvious feature is that many have mastered the art of invisibility, easily blending into their environment to evade predators or surprise prey.

However, research into this fascinating natural behavior has been hampered because it is not possible to culture cephalopod skin cells in the lab, and establishing frameworks for describing how these cells manipulate light has proven challenging.

But now, a group working at the University of California, USA, report that they have successfully used mammalian cells to replicate the tunable transparency of squid skin. The researchers presented their incredible findings at the ACS 2023 Spring National Meeting, summarizing research published earlier in the year in ACS Biomaterials Science & Engineering.

The team concentrated their research around leucophores, a special type of cephalopod cell made up of light-scattering reflectin proteins that make the cells appear bright white. They used genetic engineering to create reflectin nanostructures in human embryonic kidney cells and evaluated their refractive indices under physiologically relevant conditions.

"We wanted to engineer mammalian cells to stably, instead of temporarily, form reflectin nanostructures for which we could better control the scattering of light," says Alon Gorodetsky, Ph.D., the principal investigator on the project. "Then, at a cellular level, or even the culture level, we thought that we could predictably alter the cells’ transparency relative to the surroundings or background."

The authors report that their findings could help scientists better understand squid skin cell behavior, proving useful in more advanced imaging techniques and leading to a better understanding of cell growth and development as a whole.