pharmacoactive molecule is bound to a small magnetic particle, and the particle is
guided to its in vivo target through the use of magnetic fields. In the latter, cancerous tumors are destroyed by injecting magnetic particles into them and then
coupling the particles to a strong radio-frequency magnetic field, resulting in large
amounts of heats being delivered locally to, and eventually destroying, the tumor.
While heterogeneous catalysis is a traditional area of chemistry and is not usually classified as an application of nanoparticles, a recent development in cleanerburning fuels is worth mentioning here. Two major manufacturers of diesel automobiles in Europe, Peugeot–Citro ¨en and Ford, inject sub-10 nm CeO 2 nanoparticles
(called by the trade name EOLYS TM, manufactured by the French company Rhodia) into diesel fuel before it is burnt in the engine. This results in an in situ catalyst that not only improves fuel efficiency but also greatly reduces the emission of
particulates. Were the particles not sub-10 nm, it would not be possible to make
homogeneous dispersions in the diesel fuel. It is expected that more than a million
diesel automobiles will incorporate such systems by the year 2005. Another area
where large quantities of nanoparticulate oxide materials are expected to be consumed is in the preparation of transparent sunscreens for topical application. Traditionally, sunscreens are applied as opaque creams. The active principle is a ZnO
powder that absorbs most of the UV radiation incident upon the skin. There is
great interest however, in material that can be sprayed on, and that is invisible. For
this, the ZnO particles have to be sub-100 nm.
Acknowledgments
I thank the office of the Dean of Engineering, UCSB for a seed grant. In writing
this review, I have benefited greatly from discussions with Paul O’Brien and his
group in Manchester during a recent visit made possible by a grant from the Royal
Society of Chemistry. Susanne Stemmer is thanked for inputs on bulk oxide materials. My many coauthors in the area are acknowledged in the papers listed;
Michael Rajamathi and Moumita Ghosh are thanked for their help in collating
references. Larken Euliss is thanked for critically reading the manuscript.
References
1 M. Faraday, Philos. Trans. R. Soc.
London, 1857, 147, 145–181.
2 M. Jose ´-Yacama ´n, L. Rendo ´ n, J.
Arenas et al., Science, 1996, 273, 223–
225.
3 Oxford English Dictionary at http://
dictionary.oed.com/
4 A. Fojtik, H. Weller, U. Koch et al.,
Ber. Bunsen-Ges. Phys. Chem., 1984, 88,
969–977.
5 M. L. Steigerwald, A. P. Alivisatos,
J. M. Gibson et al., J. Am. Chem. Soc.,
1988, 110, 3046–3050.
6 C. B. Murray, D. J. Norris, M. G.
Bawendi, J. Am. Chem. Soc., 1993,
115, 8706–8715.
7 M. Brust, M. Walker, D. Bethell et
al., J. Chem. Soc., Chem. Commun.,
1994, 801–802.
8 R. G. Nuzzo, D. L. Allara, J. Am.
Chem. Soc., 1983, 105, 4481–
4483.
5 Oxide Nanoparticles
110
guided to its in vivo target through the use of magnetic fields. In the latter, cancerous tumors are destroyed by injecting magnetic particles into them and then
coupling the particles to a strong radio-frequency magnetic field, resulting in large
amounts of heats being delivered locally to, and eventually destroying, the tumor.
While heterogeneous catalysis is a traditional area of chemistry and is not usually classified as an application of nanoparticles, a recent development in cleanerburning fuels is worth mentioning here. Two major manufacturers of diesel automobiles in Europe, Peugeot–Citro ¨en and Ford, inject sub-10 nm CeO 2 nanoparticles
(called by the trade name EOLYS TM, manufactured by the French company Rhodia) into diesel fuel before it is burnt in the engine. This results in an in situ catalyst that not only improves fuel efficiency but also greatly reduces the emission of
particulates. Were the particles not sub-10 nm, it would not be possible to make
homogeneous dispersions in the diesel fuel. It is expected that more than a million
diesel automobiles will incorporate such systems by the year 2005. Another area
where large quantities of nanoparticulate oxide materials are expected to be consumed is in the preparation of transparent sunscreens for topical application. Traditionally, sunscreens are applied as opaque creams. The active principle is a ZnO
powder that absorbs most of the UV radiation incident upon the skin. There is
great interest however, in material that can be sprayed on, and that is invisible. For
this, the ZnO particles have to be sub-100 nm.
Acknowledgments
I thank the office of the Dean of Engineering, UCSB for a seed grant. In writing
this review, I have benefited greatly from discussions with Paul O’Brien and his
group in Manchester during a recent visit made possible by a grant from the Royal
Society of Chemistry. Susanne Stemmer is thanked for inputs on bulk oxide materials. My many coauthors in the area are acknowledged in the papers listed;
Michael Rajamathi and Moumita Ghosh are thanked for their help in collating
references. Larken Euliss is thanked for critically reading the manuscript.
References
1 M. Faraday, Philos. Trans. R. Soc.
London, 1857, 147, 145–181.
2 M. Jose ´-Yacama ´n, L. Rendo ´ n, J.
Arenas et al., Science, 1996, 273, 223–
225.
3 Oxford English Dictionary at http://
dictionary.oed.com/
4 A. Fojtik, H. Weller, U. Koch et al.,
Ber. Bunsen-Ges. Phys. Chem., 1984, 88,
969–977.
5 M. L. Steigerwald, A. P. Alivisatos,
J. M. Gibson et al., J. Am. Chem. Soc.,
1988, 110, 3046–3050.
6 C. B. Murray, D. J. Norris, M. G.
Bawendi, J. Am. Chem. Soc., 1993,
115, 8706–8715.
7 M. Brust, M. Walker, D. Bethell et
al., J. Chem. Soc., Chem. Commun.,
1994, 801–802.
8 R. G. Nuzzo, D. L. Allara, J. Am.
Chem. Soc., 1983, 105, 4481–
4483.
5 Oxide Nanoparticles
110