Chemical technology news from across RSC Publishing.
Instant insight: The shape of things to come
20 August 2007
Paul Midgley, Edmund Ward, Ana Hungria and John Meurig Thomas discuss using nanotomography to take a 3D glimpse at the nanoworld.
A montage of projections of a scanning electron tomogram. It shows the distribution of catalyst nanoparticles within a mesoporous silica support.
There is little doubt that medicine has benefited greatly from the ability to visualise the internal organs of the human body using a variety of radiation including X-rays, positrons, ultrasound and nuclear magnetic resonance. The invention of the 'cat-scan', or CT-scan, in the 1960s enabled such views to be further improved by allowing a full three-dimensional reconstruction of the internal architecture of the body. The basis behind the reconstruction is the technique of tomography, from the Greek word 'tomos' meaning 'slice' or 'section', in which a series of images, or projections, is used to create a three-dimensional view by back-projecting these images into a 3D space in a computer.
In the chemical sciences, relatively little advantage has been taken of tomographic techniques even though it has long been clear that the spatial resolution ultimately attainable by the use of X-rays and electron beams far exceed those associated with CT scans and NMR imaging of the human body.
The shape, size and distribution of nanoparticles and nano-structures are all key to their function and the need for tomographic methods applicable to chemical systems (ranging from the physical to the biological) is therefore pressing, just as it is in the engineering and earth sciences.
In our Critical Review we investigate nanotomographic methods that are open to the materials-oriented chemist and present a range of illustrative examples taken from nanoscale chemistry, along with contiguous sub-disciplines encompassing parts of biology and medicine.
The need for three-dimensional visualisation and analysis at high spatial resolution is likely to increase as nanoscience and nanotechnology become increasingly important - nanotomography will play a key role in understanding structure, composition and physico-chemical properties at the nanoscale.
Read the full Critical Review 'Nanotomography in the chemical, biological and materials sciences' in issue 9 of Chemical Society Reviews.
Link to journal article
Nanotomography in the chemical, biological and materials sciences
Paul A. Midgley, Edmund P. W. Ward, Ana B. Hungría and John Meurig Thomas, Chem. Soc. Rev., 2007, 36, 1477
Paul Midgley's website at the University of Cambridge
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Also of interest
Direct visualisation, by aberration-corrected electron microscopy, of the crystallisation of bimetallic nanoparticle catalysts
Edmund P. W. Ward, Ilke Arslan, Paul A. Midgley, Andrew Bleloch and John Meurig Thomas, Chem. Commun., 2005, 5805
High-resolution transmission electron microscopy: the ultimate nanoanalytical technique
John Meurig Thomas and Paul A. Midgley, Chem. Commun., 2004, 1253
Z-Contrast tomography: a technique in three-dimensional nanostructural analysis based on Rutherford scattering
Paul A. Midgley, Matthew Weyland, John Meurig Thomas and Brian F. G. Johnson, Chem. Commun., 2001, 907