Research Highlight

Molecular sieves for nanotubes

Biplab Das

doi:10.1038/nindia.2008.231 Published online 30 June 2008

An Indian research team has devised a type of molecular sieve containing iron and cobalt that aid in making carbon nanotube production1. The molecular sieves play the role of catalysts in synthesizing carbon nanotubes, which have huge practical applications, especially in biomedicine.

Far thinner than the width of a human hair, carbon nanotubes are promising nanostructures. These nanotubes can be used on the cellular level, including the delivery of therapeutic molecules into cells. Many studies have shown that biological molecules like peptides, medicinal molecules, and nucleic acids, when bonded to carbon nanotubes, are delivered more safely and effectively into cells than by traditional methods.

A recent research has shown that being water-soluble single walled carbon nanotubes (SWNT) can easily be translocated into cytoplasm or nucleus of a cell through its cell membrane. This produces no toxic effects. But, increasing their yield at lab has been a challenge to researchers.

Using a special hydrothermal method, the researchers sysnthesized a porous MCM-41 (mobile composition of matter 41) incorporating a mixture of iron and cobalt. This gave rise to molecular sieves and worked as catalyst in the yield of SWNTs.

"Using optimum conditions, MCM-41 containing iron and cobalt showed the best results for selective SWNTs with high yield when compared with either only iron with MCM-41 or only cobalt with MCM-41," says lead researcher A. Pandurangan from the Department of Chemistry at the Centre for Nanoscience and Nanotechnology of Anna University in Chennai.


  1. Somanathan, T. et al. Catalytic activity of Fe, Co and Fe-Co-MCM-41 for the growth of carbon nanotubes by chemical vapour deposition method. Appl. Surf. Sci. 254, 5643-5647 (2008) | Article |