Scientists have figured out how to make an invisible man. This requires the ability of an octopus. This was written by researchers from the University of California at Irvine in their article in Nature Communications.
Octopuses, squids, and other sea creatures have a wonderful ability to disappear, for this, they have special tissues in their organisms that control the transmission and reflection of light. Scientists have managed to grow similar human cells. The researchers were inspired by the structure of the skin of cephalopods, endowing mammalian cells with the same custom transparency and light-scattering characteristics.
“For thousands of years, people have been fascinated by the idea of transparency and invisibility, which inspired them to philosophical speculations, science fiction works and numerous academic studies,” says lead author of the study, Atrowley Chatterjee. “Our project, which is clearly located in the field of science, is aimed at developing and constructing cellular systems and tissues with controlled properties for the transmission, reflection and absorption of light.”
The researchers took as a basis the female squid Doryteuthis opalescens, which can change the color of their mantle from transparent to opaque white, thereby avoiding predators. Scientists took samples of intercellular protein particles involved in this transformation, and found a way to introduce them into human cells.
This type of squid has specialized reflective cells called leukophores – they can change the way light is scattered. Inside these cells are leukosomes, particles associated with the membrane, which are made up of proteins known as reflexins – they can reproduce rainbow camouflage.
In their experiments, researchers cultured human kidney embryonic cells and genetically engineered them to express reflexin. They found that a protein can assemble into particles in the cytoplasm of cells in an disordered arrangement. They also saw through optical microscopy and spectroscopy that the introduced structures made the cells change their light scattering.
“We were amazed to find that the cells not only express reflexin, but also pack the protein into spheroidal nanostructures and distribute them over the bodies of the cells,” said Alan Gorodetsky, co-author of this study. – Through quantitative phase microscopy, we were able to determine that the protein structures had different optical characteristics compared to the cytoplasm inside the cells; in other words, they behaved optically in much the same way as their native cephalopod leucophores”.
In another important part of the study, the team checked whether reflectivity can be turned on and off using external stimuli. They placed cells between coated glass plates and applied various concentrations of sodium chloride. By measuring the amount of light that was passed through the cells, they found that those cages that were exposed to higher levels of sodium scattered more light and were released more from the environment.
“Our experiments showed that these effects are manifested in engineered cells, but not in cells that lack reflexin particles, demonstrating a potentially valuable method for adjusting the light-scattering properties in human cells,” Chatterjee said.
According to scientists, new knowledge will help open the possibility of using reflection as a new type of biomolecular marker for medical and biological microscopy.