07 April 2016

Neurons from liposomes

Synthetic "nerves" work in the light

Kirill Stasevich, "Science and Life" based on the materials of the University of Oxford: Scientists create first light-activated synthetic tissues

Researchers from Oxford have created an artificial analogue of the nervous chain: synthetic cells packed with a 3D printer into a kind of conductive tissue were able to conduct an electrical pulse. Let's say right away that the cells in this case are tiny drops of water with a volume of 50-100 picoliters enclosed in a single–layer lipid membrane. It is clear that such drops contained not only water, they also contained DNA with genes encoding transmembrane proteins, and all the necessary apparatus for protein synthesis. Transmembrane proteins synthesized in the "cell" formed a through channel in the membrane – so an "intercellular contact" appeared between two drops, through which an electrical signal could slip. The work of the "nervous chain" depended on lighting – there was also a special photosensitive protein in the "cells", which, under the influence of light, bound to DNA and activated the genes of transmembrane proteins recorded in it.

Dense orderly stacking of droplets was achieved, as mentioned above, using a 3D printer. The technology of three-dimensional printing from such "cells" has been developed for a long time, but now the authors of the work had to develop a new recipe for them, so that both the "cells" themselves and the molecular machines contained in them for transcription (synthesis of RNA copies to DNA) and translation (protein synthesis to RNA), passing through the printer, they would have remained in working condition.

You can learn more about "synthetic nerves" from the article in Science Advances (Light-activated communication in synthetic tissues). The main achievements of Michael J. Booth and his colleagues consider that they managed to build a light switch into the nervous chain, and that the propagation of the pulse was not limited to two "cells", that the signal went further – to the third drop, the fourth, the tenth, etc.


The signal transmission scheme along the chain of "synthetic cells": genes synthesize transmembrane proteins under the influence of light, which are embedded in membranes and form a channel for transmitting an electrical pulse. (Illustration by Michael Booth / University of Oxford).

In such an artificial system, it is quite possible to study some patterns of pulse propagation through conductive tissues, but in the future, researchers want to combine artificial cells with real ones. However, two technological problems need to be solved for this: firstly, the droplet complexes printed by a 3D printer "live" in an oily environment, and real cells need an aqueous solution; secondly, the pore proteins in artificial cells are embedded in a single-layer lipid membrane, whereas in real cells it is two-layered, and it is unknown, whether a transmembrane protein pore will form between them. Maybe the contact between an artificial and a real cell will be organized in the form of a synapse, when a certain space remains between the cell membranes, and the transmission of the pulse occurs with the help of special chemical molecules-neurotransmitters. It's too early to talk about practical application here, although, if you let your imagination run wild, you can imagine how in the future we will be able to create synthetic patches for muscles, or even for the brain.

Portal "Eternal youth" http://vechnayamolodost.ru  07.04.2016

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