Dendrimers are particles consisting of tree-like branches extending in a sphere from a central core.
Dendrimers belong to the class of polymericcompounds whose molecules have a large number of branches. When they are obtained, with each elementary act of molecular growth, the number of branches increases. As a result, with an increase in the molecular weight of such compounds, the shape and rigidity of the molecules change, which, as a rule, is accompanied by a change in the physicochemical properties of dendrimers, such as intrinsic viscosity, solubility, density, etc.
The synthesis of dendrimers is carried out in such a way thatduring the growth of the polymer molecule, there was no connection of the growing branches, no association of molecules with each other. Likewise, the branches of one tree or the crowns of adjacent trees do not grow together. The "construction" of such molecules is carried out according to a predetermined plan, for example, using reacting groups of three types (A, B, and C), which must satisfy the requirements of a certain logical scheme: each group cannot react with its own kind (A does not interact with A and etc.), groups A and B can react with each other, but each of them cannot react with C, group C must be able to transform at a certain moment into group A.
Illustration of a dendrimer with tiny tentacles that get smaller as they branch further from the nucleus.
Newcastle University
The larger the dendrimer grows, the more tentacles it grows and the less space there is between them. It turned out that at some point this makes them invisible to the immune system.
Sensors called recognition moleculescomplement images (CPR), help immune cells to recognize foreign pathogens such as bacteria and viruses, thanks to the unique patterns on their surface. These CPR molecules can respond to patterns that repeat in the range of 2 to 15 nanometers. When scientists created dendrimers with tentacles less than 1 nm apart, it turned out that the CPR molecules could not detect them.
The study authors explain that, for example,such very tiny dendrimers can be used as carriers to deliver drugs to the body without triggering the immune system. For example, these tiny particles can protect implants from immune rejection. The fact is that the activation of the complement system as the defense mechanisms of our immune system sometimes leads to inflammation and also induces anaphylactic reactions.
The study was published in the journalNature Communications.
Read more
See the fastest hypersonic aircraft
The slowing down of the Earth's rotation caused the release of oxygen on the planet
What Happens to Cryptocurrency: From Rise and Fall to State Recognition