Chemically controlling carbon nanotubes' (CNTs) assembly could lead to new biomaterials, say scientists in Italy.

Maurizio Prato and Mildred Quintana at the University of Trieste have developed a chemical method to manipulate CNTs using hydrogen bonding networks. Normally carbon nanotubes assemble in tight bundles that are difficult to disperse and manipulate, says Prato. 'Through intermolecular interactions, carbon nanotubes can be self-assembled into many different structures' he explains. 

The team used two reactions to add components of DNA, know as thymines, around the surface of the CNTs. The thymine units are able to form strong hydrogen bonds as they contain both a C=O acceptor and an N-H donor bond. 'The integration of organic moieties able to perform hydrogen bonding or any other supramolecular recognition facilitates [the CNT's] handling,' explains Prato.

Davide Bonifazi who specialises in molecular architectures at the University of Namur in Belgium says 'this is the first example of nanostructured CNT-based architectures truly controlled by non-covalent molecular recognition.'

Prato says the team were seeking a chemical approach to manipulating CNTs, rather than traditional physical approaches such as chemical vapour deposition, so that CNTs could be manipulated on a smaller scale. This would make them more useful in applications such as small electronics devices, he says. 

Tomas Torres, an expert in molecular organic materials at the Autonoma University of Madrid, Spain, says this is an 'outstanding contribution' which could open up many opportunities for practical use of carbon nanotubes. 'This approach represents a powerful tool since it could be used to produce dispersions in dipolar aprotic solvents, and holds a great potential for application to other carbon nanostructures,' he adds.

In future, Prato says functionalising carbon nanotubes with biomolecules might produce new biocompatible materials that could also show plasticity and be adaptable. 'Culturing of cells on aligned carbon nanotubes might produce novel scaffolds for tissue engineering, neural prosthetics or bone regeneration' he adds. 

Katherine Davies