Role of Dynamics in Self-Organisation of Amino Acids on Coinage Metal Surfaces

Biomolecules exhibit a number of subtleties in their chemistry that have profound impacts upon the roles they play in living systems. Amongst the most important are their propensity to form special kinds of chemical bonds (known as "hydrogen bonds") and their tendency to exist in two complementary mirror image ("chiral") forms. Chirality is crucial in many biological situations because left- and right-handed forms of a molecule may behave very differently when interacting with other chiral molecules. Hydrogen bonds, on the other hand, are important because they are just strong enough to be stable at room temperature, but not so strong that they cannot be severed when necessary during biological processes. Both hydrogen bonds and the phenomenon of chirality have consequently been much studied in the context of molecular biology.

Just recently, however, the behaviour of biomolecules at surfaces has received a great deal of attention, in particular focusing upon amino acids - the simple building blocks from which complex proteins are constructed according to the blueprint of DNA. Drivers for this interest include development of new biocompatible materials for medical use, biosensors (especially chirally sensitive biosensors, capable of discerning between left- and right-handed versions of otherwise identical molecules) and routes towards chiral synthesis of drug precursors (producing exclusively the left- or the right-handed version of a molecule, as required). In these efforts, the role of hydrogen bonds in dictating how molecules arrange themselves at the surface has become a key focus of attention, and appears to be strongly related to the way in which molecular chirality is manifest in the geometry of extended molecular networks. Previous studies, however, have generally been limited to reporting on the kinds of network that can be produced, but shed relatively little light on how and why they form in the way that they do. Our project aims to uncover precisely this latter type of information, through a combination of scanning probe microscopy, electron diffraction, helium atom scattering, infra-red spectroscopy and theoretical modelling. Furthermore, we aim to learn how the properties of chiral molecular networks may be tuned by interaction with hydrogen (mimicking the effects of acidity variation in solution chemistry) to alter chemical reactivity, with a view towards ultimately controlling chiral chemical reactions at surfaces.

Much of our initial attention will focus upon the structures formed by amino acids on copper surfaces, where some progress has already been made by ourselves and others. Our emphasis on the dynamic and kinetic processes by which these structures are formed sets this work apart from prior studies, however, and in addition we will incorporate work on other metals such as silver and gold, which have received far less notice in the literature to date. This phase of the project will greatly advance our understanding of the link between the short-range chirality of individual molecules and the long-range chirality exhibited by the surface networks into which they self-assemble. Subsequently, we will devote considerable efforts toward understanding the role of surface hydrogen in modifying the properties of amino acids. In living cells, biological molecules exist in aqueous solution, and the pH of the water environment can have profound effects upon the reactions that may occur. At the surface, we anticipate that varying concentrations of hydrogen may mimic variations in the acidity that are so important in solution.

Finally, we aim to combine our understanding of the manifestation of chirality at surfaces with our findings on the tuning of reactivity, in order to conduct chiral surface chemistry. Target reactions include transformation of non-chiral pyruvic acid into chiral alanine by reaction with (for example) urea, or into chiral lactic acid by reaction with hydrogen.

In addition to academic beneficiaries, working particularly in the field of surface science, we believe that our proposed work promises to significantly impact upon a range of individuals and institutions throughout the wider world. Many of these impacts derive from the possible application of our fundamental research in the development of future biophysical and biochemical technologies, including but not limited to biocompatibility, biosensing and biocatalysis, with potential to contribute towards both wealth creation and healthcare. We identify a variety of stakeholders in our research, including corporations, taxpayers and policy-makers, and propose specific strategies to ensure that an appropriate dialogue is maintained throughout the grant period and beyond.

Our engagement with industry in the field of heterogeneous catalysis already has a solid foundation through our links with collaborative partners (currently Johnson Matthey, Shell and Dow Corning) and our direct communication with the research base of these companies provides an excellent basis for efficient knowledge transfer. As the work described in this proposal progresses, we aim to develop similarly close partnerships with selected companies active in cognate biotechnologies. We therefore seek to further diversify our industrial contacts and plan to make use of initiatives available at Departmental and University level to achieve this (the Corporate Associates Scheme within the Chemistry Department at Cambridge; strong departmental ties at both institutions with biochemical/pharmaceutical companies including Merck, Johnson and Johnson, Roche, Bristol Myers Squibb, Celgene, etc.; the Research Horizons and Research Focus magazines of Cambridge and Rutgers respectively).

Engagement with the public is primarily addressed through the websites of the two partner groups, which maintain staff profiles, list of publications, explanation of techniques and summarised highlights of recent research. The aim of both groups is to communicate enthusiasm for the fundamental blue-sky aspects of our work, whilst simultaneously outlining the practical applications that may eventually follow. Work from the Cambridge group is also publicised on the Department of Chemistry website, and within the Department's broadly distributed Chem@Cam newsletter. We plan to ensure greater coverage on the University of Cambridge website in future through contact with the Office of External Affairs and Communications, which hosts a staff member dedicated to promoting the public profile of the University's scientific research. We believe this will also prove to be a valuable resource in helping us achieve coverage in the national and international press (newspapers, popular scientific periodicals, websites, etc). As an example, some of the Cambridge group's work on ammonia synthesis was recently publicised on the University website and via press release, leading to extensive coverage on technology blogs, a feature article in a chemical engineering magazine, and an enquiry from a new industrial contact.

In respect of engagement with policy-makers, we intend to foster contact with Julian Huppert, the new MP for Cambridge and a working scientist who completed his PhD within the Chemistry Department only five years ago (in biological chemistry). He has been working to represent an informed view of science within Westminster, and we plan to invite him to visit the Cambridge laboratories at the earliest opportunity, so that he can be brought up to speed on the benefits to society of biologically relevant surface science. At the same time, the Departments' Chemistry Advisory Boards provide another opportunity to present our work to influential figures in local and national establishments, as does the Cambridge College system. We furthermore expect that our links with key individuals at the Smith School of Enterprise and the Environment, at Oxford, will yield additional routes to inform policy-maker