|
|
Professor
Stephen Mann FRS |
|
Centre for Organized Matter Chemistry Tel: +44 (0) 117 9289935 Fax: +44 (0) 117 9251295 |
- Research Themes -
The aim of our research is to investigate the chemistry of organized matter. In particular, we are interested in bio-inspired chemically-derived routes to complex inorganic materials. For this, we are attempting to integrate concepts and knowledge of how organisms fabricate biominerals such as bones, shells and teeth, within a biomimetic approach to the synthesis of organized inorganic-based materials with structural hierarchy and morphological complexity across a range of length scales [refs 1, 4].
Several areas are currently being explored. These include the use of proteins with micellar structures as small-scale reaction environments for the production of bioinorganic nanocomposites with magnetic and quantum dot properties [ref 5] and the application of organized supramolecular assemblies of surfactant molecules as templates for the oriented nucleation of inorganic crystals [ref 2]. Recently, we have used microemulsions to induce the formation of inorganic materials with complex forms such as microskeletal calcium phosphates [ref 3] and honeycombed thin films and hollow micro-shells of calcium carbonate [refs 6].
Schematic showing the mechanism of formation of calcium carbonate microsponges in water-in-oil microemulsions
Walsh, D., Lebeau, B. L. and Mann, S. Adv. Mater. 11, 324-328 (1999).
We
are also exploring the use of biological micro-structures for the template-directed
synthesis of organized inorganic architectures. We have used superstructural
arrays of bacterial filaments to fabricate ordered silica macrostructures [ref
7], two-dimensional protein crystals for the synthesis of ordered superlattices
of quantum-sized cadmium sulfide nanocrystals [ref 8], and tobacco mosaic virus
for the fabrication of inorganic nanotubes [ref 9].
Other work currently under investigation involves the template-directed
synthesis of ordered silica-surfactant mesostructures with covalently linked
organic functionalities [refs 10-12] and the synthesis of lamellar magnesium
organosilicates incorporating functionalized arrays of organic moieties [ref
13].
Schematic showing synthesis route to a dye-containing mesostructured silica (MCM-41).
Very
recently, we have developed a new approach using inorganic nanoparticles to
prepare magnetic spider silk! [ref 14].
We are also investigating new biomolecular recognition approaches to the
self-assembly of inorganic nanoparticles into superstructures [refs 15, 16].
Schematic showing biotin-streptavidin cross-linking of inorganic magnetic nanoparticles encapsulated within the protein ferritin.
New synthetic approaches to self-assembled nanostructures are being studied. For example, we use microemulsions as confined reaction media for the synthesis and self-assembly of inorganic nanoparticles into organized superstructures such as linear chains of prismatic nanoparticles [ref 17].
Schematic showing self-assembly of surfactant-coated nanorods.
In general, projects can involve synthetic methods (materials chemistry) and/or structural characterization (electron microscopy, X-ray diffraction, FTIR and solid state NMR spectroscopies. Interdisciplinary projects on environmental or biological materials (biomineralization) and polymer-inorganic hybrid materials are also available.
References
1. Mann, S. Nature 365, 499-505 (1993).
2. Heywood, B. R. and Mann, S. Adv. Mater. 6, 9-20 (1994).
3. Mann, S. and Ozin, G. A. Nature 382, 313-318 (1996).
4. Mann, S. et al.Chem. Mater. 9, 2300-2310 (1997).
5. Douglas et al. Science 269, 54-57 (1995).
6. Walsh, D., and Mann, S. Nature 377, 320-323 (1995).
7.
8. Shenton, W. et al. Nature 389, 420-423 (1997).
9. Shenton, W., et al. Adv. Mater. 11, 253-256 (1999).
10. Burkett, S. L. et al. Chem Commun.,1367-1368 (1997).
11. Fowler, C. F. et al. Chem Commun., 1769-1770 (1997).
12. Fowler, C. E., Lebeau, B. and Mann, S. Chem. Commun. 1825-1826 (1998).
13. Burkett, S. L. et al. Chem. Mater.9, 1071-1073, (1997).
14. Mayes, E. L., Vollrath, F., and Mann S. Adv. Mater. 10, 801-805 (1998).
15. Li, M., Wong, K. K. W. and Mann S. Chem. Mater. 11, 23-26 (1999).
16. Shenton, W., Davis, S. A. and Mann S. Adv. Mater. 11, 449-452 (1999).
17. Li M, Schnablegger H and Mann S. Nature 402, 393-395 (1999).