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Posted: Jan 20, 2016
Subatomic silver clusters that self-assemble on cyclic peptide nanotubes
(Nanowerk News) The weak attractions between molecules are responsible for, among other things, the existence of solid, liquid or gas materials as well as some of its transformations. For instance, in it’s liquid state, water molecules are held together by the huge number of weak hydrogen bonds that are established between different water molecules.
These weak non-covalent interactions are the basic building blocks of life, playing key roles in essential biological processes such as genetic coding, their translation into proteins, regulation of cellular processes, etc.
Proposed model for the coupling between SCPNs and Ag3 clusters and general AFM images for hybrid model structures.
Exploring tiny things
In the nanoworld everything behaves different than at the normal scale. These remarkable and different properties of matter at the nanosize have fueled, in recent years, the interest towards nanotechnology in the scientific community. At this scale (only visible through the electronic microscope), the design of new materials and, especially, the ability to manipulate their properties at the molecular level, have emerged as key to the development of innovative applications.
In this context, weak interactions between molecules play a crucial role, as from its behaviour largely depends on the viability of manufacturing and self-assembly of these materials in an efficient and controlled form.
The size of metal nanoparticles determines their properties. When a nanoparticle is so small that approaches the Fermi level of an electron (only comprises a few metal atoms) new properties emerge from this, so called, “cluster” of metal atoms. That case it is known as "sub-nanometric metal clusters", and at this level they do not behave as formal metals and they show properties that are typical of the organic molecules.
Molecular metal clusters have special characteristics that would make them ideal candidates for different applications, such as catalysts, magnetic materials or antimicrobial properties. Therefore, it is very important to develop new methods to allow to manipulate them at the nanometer scale.
These peptidic nanotubes incorporate an organic molecule that interacts with the metal clusters. Consequently, the metals clusters interacting with the nanotube end up aligned along the nanotube.
The discovery of these new interactions has given researchers the ability to change the properties of nanotubes, conferring them a metal surface. That can be of great interest to the development of new materials such as the molecular-wires and small machines in a molecular level.