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a.m.squires@rdg.ac.uk
2002-4 Postdoctoral research associate, Cavendish Laboratory, Cambridge
2004-5 Research Fellow, Cavendish Laboratory/Dept of Chemistry, Cambridge
Our research interests primarily focus on biomaterials and biomolecule assemblies. These include lipid bilayers, protein fibres, and elastic protein networks.
We are interested in developing methods to control, align and investigate these systems without their needing to be dehydrated or crystallised. Molecular alignment yields a wealth of additional structural information on the biomolecules themselves. In addition, dynamic time-resolved experiments probing the timescales of changes in molecular alignment can help us to understand the material's viscoelastic mechanical properties.
The main research technique we employ is x-ray scattering, both wide- and small-angle. We are also interested in developing new methods based on polarised vibrational spectroscopy on aligned protein samples.
The structures and materials we have investigated so far fall into three categories
Also on this page:
Amyloid fibrils are insoluble protein aggregates that have been associated with a range of diseases including BSE, Alzheimer’s, Parkinson’s and Creutzfeldt-Jakob Disease (CJD). The fibrils can be created in the laboratory from a range of different proteins and peptides. Whatever the starting protein, the same structure is always found at the core of the fibril. Stacks of parallel peptide strands running perpendicular to the fibril axis hydrogen-bond to form extended beta-sheets (above, left). These then stack across the fibril axis, and then intertwine to fibrils a few nanometres in diameter, and up to several microns in length (above, right).
More information on our work on these fibres may be found here .
When amphiphilic molecules such as lipids are mixed with water, they can self-assemble to form mesophases with a range of different structures. Some are based on bilayers similar to cell membranes. Others - the "bicontinuous cubic" phases - are based on exotic mathematical shapes called triply periodic minimal surfaces. These structures have applications in biosensors, templating, and drug delivery. We are interested in controlling the different mesophases, and in understanding the kinetics and geometric pathways of their formation and inter-conversion. Such pathways are shown in these Quicktime movies.
Much of this work has been carried out with Professor Richard Templer, Professor John Seddon, and Dr Oscar Ces, at the Biophysical and Interfacial Chemistry sections at Imperial College, London.
My work analysing synthetic liquid crystal elastomers using dynamical mechanical, optical and x-ray scattering analysis is summarised in this Powerpoint presentation. This work has been carried out with Professor Eugene Terentjev in the BSS sector at the Cavendish laboratory in Cambridge. We have ongoing collaborations with Professor Terentjev's group in projects looking at nanotube-elastomer composites, and gelatin.