dendrimer (rus. дендример otherwise арборол) — macromolecule with symmetrical regular branching tree structure.

Description

Dendrimer branches have a common centre. A first generation dendrimer has one branch point in each branch, a second generation dendrimer has two branch points, etc. The structure of dendrimers is achieved through their multistep synthesis process (see Fig.). Dendrimers have been actively studied since 1980s, and hundreds of different types of such macromolecules have already been obtained.

Dendrimers of the third and higher generations are characterised by their high-density molecular structures and have a nearly spherical shape. Dendrimer solutions have a much lower viscosity than solutions of other substances with a similar molecular weight. The properties of dendrimers are largely determined by the type of functional groups on their surface. Thus, dendrimers with hydrophilic end groups (e.g., carboxyl) are soluble in water, and those with fluoro-organic end groups are soluble in supercritical CO2.

Currently, dendrimers have been actively investigated to determine the possibilities of their use in various fields. Dendrimers can serve as a container for systems of metal nanoparticles of practically the same size that can be used as catalysts of chemical reactions in the manufacturing of electronic devices and special coatings. Dendrimers with photochromic groups are able to convert light energy, which makes them suitable for use in optical devices. Dendrimers can form complexes with other molecules, and the stability of such complexes is determined by the state of the environment. This opens up new possibilities for using dendrimers in medicine as carriers for the targeted delivery of genes or drugs.

As the size of macromolecules can be controlled and reproduced with great precision, dendrimers are already being used for calibration in mass spectrometry, electron and atomic spectroscopy, and ultrafiltration. Dendrimers containing heavy metals are used in medical diagnostics as radiopaque substances.

Illustrations

Synthesis of dendrimer growing from the core (2D-projection).
Synthesis of dendrimer growing from the core (2D-projection).

Authors

  • Khokhlov Alexey R.
  • Govorun Elena N.

Sources

  1. Dendrimers and other dendritic polymers / Ed. by J.M. Frechet, D.A. Tomalia. — N.Y.: Wiley & Sons, 2001.
  2. Semchikov Ju. D. Dendrimers, a new class of polymers (in Russian) // Sorosovskijj obrazovatel'nyjj zhurnal. 1998. #12. 45–51 pp.
  3. Levickijj M.M. Dendrimers / / Online Encyclopedia Krugosvet (in Russian). — www.krugosvet.ru/enc/nauka_i_tehnika/himiya/DENDRIMERI.html (reference date: 12.12.2011).

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