The experiment carried out by American scientists does not yet mean the appearance of the invisible man, but the first step in this direction, one might say, has already been taken.
Some animals are able to change the light transmission of their tissues for camouflage purposes. This ability is possessed, for example, by the opalescent squid (Doryteuthis opalescens), whose camouflaging properties served as a starting point for an experiment with human cells by scientists from the University of California, Irvine.
“For millennia, people have been fascinated by dreams of transparency and invisibility that have inspired philosophers, science fiction writers and many scientists,” said study leader Atrauli Chatterjee. "Our project, definitely in the scientific field, is focused on designing cellular systems with controlled ability to transmit, reflect and absorb light."
The opalescent squid can quickly switch stripes on its mantle from near-transparency to matte whiteness, allowing it to elude predators. This squid has special reflective cells - leukophores - that can change their ability to scatter light. Inside these cells are leucosomes - membrane-bound particles composed of special proteins - reflexins.
In their experiment, scientists grew human kidney cells by genetically altering them so that they could produce reflectin. Then it was found that proteins are collected in the cellular cytoplasm into particles, and these structures, in turn, change the ability of cells to scatter light.
However, the authors of the study did not stop there, and continued experiments with modified cells, now acting on them with a solution of sodium chloride in various concentrations and simultaneously measuring their light transmittance. As a result, it turned out that the higher the sodium chloride level, the more cells scatter light.
According to scientists, the creation of an invisible man is still in the realm of fantasy, but they nevertheless managed to prove the very possibility of creating human cells with adjustable optical properties.