These curved blue lines are not modern art, but a bluish -colored rat brain – and a very special one. Because it has been colored with a new method that allows for the first time to mark complete tissue.
In the chemical coloring, specific proteins can be colored with the help of antibodies and thus observed in terms of functioning. This shows, for example, how different cells react to environmental influences such as illnesses and their treatments. But: “To examine the molecules in cells, you have to break into tissue into individual cells or cut into thin slices, since light and chemicals that are needed for the analysis cannot penetrate deeply into the tissue,” explains Kwanghun from the Massachusetts Institute of Technology (with). It would make it much easier for researchers to be able to color complete tissue samples without having to cut them.
But that is difficult: “Imagine you marinate a thick steak by simply diving it in sauce. The external layers absorb the marinade quickly and intensely, while the inner layers remain largely untouched if the meat is not soaked for a long time. ”To put it in a biochemical manner, the antibodies (the“ marinade ”) quickly bind to their target protein, penetrate the tissue But only very slowly. “As a result, it may take weeks for these molecules to diffuse into intact organs, which makes even chemical processing of tissues at the organ level practically impossible and extremely slow,” explains Chung.
In order to avoid this problem, Chung and his team have now accelerated the hike of the antibodies through the tissue by giving up electrical fields. As a result, they were able to mark proteins in cells of the entire brain of mice and rats and even in whole mouse embryos, mouse organs such as lungs and heart and in parts of the brain tissue of larger animals, including us humans. The method only needed one day per copy. This is extremely fast compared to previous methods and is now completely new to research.