04 June 2008

Amyloids as a nanomaterial

Amyloid plaques are most often associated with Alzheimer's disease – the most common cause of senile dementia. But amyloidosis – protein metabolism disorders of heterogeneous origin, in which the glycoprotein amyloid is deposited extracellularly in tissues – can manifest itself in a variety of organs, causing severe and practically incurable diseases.

However, amyloids are not only substances that indicate pathologies. They can also be used as nanomaterials.

According to Ehud Gazit and Yitzhak Cherny, the possibilities of using supramolecular associates of amyloids are much higher than nanostructures based on synthetic polymers – mainly because these building blocks can be responsible not only for mechanical, but also for biological properties.

Even in nature, amyloids are not only abnormal, improperly bound proteins, they are physiologically significant substances. For example, they are an important protective material for the shells of fish and bird eggs. Amyloids are also involved in the formation of coatings on the surface of bacterial cells that protect them from antimicrobial compounds, facilitating the attachment of bacterial cells to surfaces.

Amyloid fibrils are bundles of highly ordered protein strands assembled by the type of ladder bundles, which can reach several micrometers in length. In cross section, amyloids are hollow cylinders. Despite the fact that amyloid fibrils are proteins, their properties are much closer to synthetic polymers than to ordinary globular proteins. The mechanical properties of amyloids often resemble the properties of a spider web, which can be stronger than steel, and can also be stretched many times without breaking – these properties still cannot be reproduced for synthetic fibers.

Researchers from Tel Aviv University note that the self-organization of amyloids, along with their plasticity, allows us to consider them as very attractive building blocks for creating new nanostructures and nanomaterials.

The properties of these building blocks can be easily adjusted by using simple biological techniques. For example, controlled adjustment of biologically compatible surfaces in flow analysis systems in medicine or biotechnology can be performed. It is also possible to use amyloid hydrogels for encapsulation and controlled release of drugs or as scaffolding for cell culture or tissue formation. Functional proteins, such as enzymes, can also be associated with amyloids.

Amyloid fibrils can also be used as matrices for creating nanostructures. For example, it is possible to create a conductive coaxial nanocable by filling amyloid nanotubes with silver and coating them with gold.

The article Amyloids: Not Only Pathological Agents but Also Ordered Nanomaterials is published in Angewandte Chemie International Edition, Volume 47 Issue 22, Pages 4062-4069.

Portal "Eternal youth" www.vechnayamolodost.ru according to the materials ChemPort.Ru


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