Molecular Imprinting
Through molecular imprinting or molecular embossing of polymer nanoparticles, technically adapted, fully synthetic affinity receptors can be produced, which offer new production possibilities for biotechnological, biomedical and chemical processes.
Molecular recognition plays a decisive role in biological processes in nature for the respective biological effect.
The immune response , in which antibodies are formed in response to very small amounts of antigen , or the energy saving through enzymes that can stabilize the transition state of a reaction to be catalyzed, are examples of a specific binding between biological host molecules and certain molecular structures.
The high selectivity of these natural systems is z. B. achieved with enzymes by complementary shapes to a substrate to be stored on the enzyme surface. Enzymes are used today as biocatalysts in many technical applications , but in this respect they have a decisive disadvantage due to their instability.
Molecular imprinting offers an alternative to these natural biocatalysts through the use of synthetic polymers.
The result is a matrix that has an affinity for biomolecules with the advantages of a chemically stable base substance.
principle
A polymer network is created around a molecule that acts as a template or template by means of cross-linking polymerization . The template for the molecule that is later to be selectively recognized is enclosed by the polymer.
The template is then washed out of the crosslinked polymer again. What remains is a cavity in the polymer, which is referred to as the imprint and whose shape and polarity distribution ( dipoles , hydrogen bonds , hydrophobic interactions) are complementary to the original.
The area around this cavity thus enters into specific interactions with the template molecule and shows a pronounced affinity for these molecules .
With molecular imprinting, specific binding sites, similar to those in enzymes or antibodies, can be created in cross-linked, synthetic polymers.
Applications
Structure recognition elements that form a strong and selective bond with molecules can be used as tough, sensitive receptors in trace analysis of compounds.
Further possibilities are the separation of undesired compounds from food or body fluids (e.g. blood purification), a preparative separation ( racemate separation) necessary in the industrial production of fine chemicals or the use as artificial enzymes.
literature
- Makoto Komiyama: Molecular imprinting: from fundamentals to applications . Wiley-VCH, Weinheim 2003, ISBN 3-527-30569-6 (English).