In a groundbreaking discovery, scientists have successfully replicated the tunable transparency of certain squid skin cells in mammalian cells that can be cultured in the lab.
Squids and octopuses have long been known for their impressive ability to blend into their environment through camouflage due to the chromatophores present in their skin.
Just about everything squids do is interesting, but the way they can change their pattern of pigmentation with respect to the substratum is particularly striking. When on a light background, a squid tends to contract its pigment-containing cells so that the pigment becomes concentrated in tiny, widely spaced flecks; the body as a whole thus becomes lighter. On a dark background, the pigment cells expand, diffusing the pigment over a larger area and making the body darker.
Editor’s Note From Seashore Life of the Northern Pacific Coast, by Eugene N. Kozloff
What are Chromatophores?
Chromatophores are cells that produce color, of which many types are pigment-containing cells or groups of cells.
Still, the exact mechanisms behind their reversibly transparent skin have remained largely unknown.
The mechanism was unknown due to the unculturable nature of cephalopod skin cells in labs.
This research could provide insights into basic squid biology and revolutionize how many cell types are imaged in the future.
Working of light scattering cells
The study, presented at the spring meeting of the American Chemical Society, focused on cephalopod cells called leucophores, which have reflectin proteins that scatter light.[1]
Atrouli Chatterjee, Alon Gorodetsky, and other team members of the University of California, Irvine introduced squid-derived genes into human cells, which produced the protein and formed light-scattering nanostructures with high refractive indices.
The researchers were then able to control the scattering of light by altering salt concentration, thus changing the opacity of the cells.
The reflectin proteins could act as genetically encoded tags to track structures in cells with advanced microscopy techniques, potentially leading to better imaging strategies for cell growth and development.
Engineering Transparent Human Cells.
Scientists at the University of California, Irvine, have engineered human cells to have similar transparent abilities to cephalopod skin, allowing for the manipulation of light transmission and reflection.[2]
Researchers drew inspiration from female Doryteuthis opalescens squid, which can dynamically switch a stripe on their mantle from nearly transparent to opaque white to evade predators.
They found a way to introduce intercellular protein-based particles from cephalopods into human cells, testing whether the light-scattering powers were transferable to other animals.
The team was able to determine that the protein structures had different optical characteristics when compared to the cytoplasm inside the cells, suggesting that these reflectin proteins could be used as a new type of biomolecular marker for medical and biological microscopy applications.
References
- Atrouli Chatterjee et al., ‘Cephalopod-inspired optical engineering of human cells’, Nature Communications, 2 June 2020, “Many of the internalized photonic architectures that enable the optical functionalities of cephalopod skin cells (including leucophores) are composed of proteins known as reflectins”, https://www.nature.com/articles/s41467-020-16151-6[↩]
- Brian Bell, ‘Scientists engineer human cells with squid-like transparency’, Phys.org, 3 June 2020, “The researchers then borrowed some of the intercellular protein-based particles involved in this biological cloaking technique and found a way to introduce them into human cells to test whether the light-scattering powers are transferable to other animals”, https://phys.org/news/2020-06-scientists-human-cells-squid-like-transparency.html[↩]
