Stuart Anthony Grant Evans

Electrocatalysis with monolayer modified highly organized macroporous electrodes

For the first time the inner surface of highly organized macroporous electrodes, obtained by electrodeposition of gold into the interstitial spaces of a self-assembled close packed array of latex beads, is modified with a monolayer of a catalyst. The combination of the increased specific surface area of these electrodes and the high catalytic rate constant of the redox mediator allows us to construct surfaces showing good electrocatalytic efficiency. As a model system the electrooxidation of NADH using nitrofluorenone mediators is studied.

Time-Resolved FRET and FLIM of Four-way DNA Junctions

Conformational transitions in a 4-way DNA junction when titrated with ionic solutions are studied using time-resolved fluorescence resonance energy transfer. Parameters characterising the transition in terms of critical ion concentration (c1/2) and the Hill coefficient for ion binding are obtained by fitting a simple two-state model using steady-state spectra. Data obtained from a fluorescence lifetime plate reader and analysed by fitting a single exponential to donor fluorescence lifetime decays are shown to be in good agreement with the parameters obtained from steady-state measurements. Fluorescence lifetimes, however, offer advantages, particularly in being independent of fluorophore concentration, output intensity, inhomogeneity in the excitation source and output wavelength. We demonstrate preliminary FRET-FLIM images of DNA junction solutions obtained using a picosecond gated CCD which are in agreement with results from a fluorescence lifetime plate reader. The results suggest that time-resolved FRET-FLIM is sensitive to subtle structural changes and may be useful in assays based on 4-way DNA junctions.

Interdisciplinary integrated research teams in an academic environment

This paper presents a discussion on the extent to which industrial R&D management techniques can be applied in an academic research environment. Working in highly integrated interdisciplinary teams has been shown to provide significant benefits in industrial R&D, yet organisational forms, reward systems and the culture of the academic environment remain a barrier to team working. A group of four research centres at the University of Edinburgh have trialled a new integrated team approach similar to the use of high-performance teams in industrial product development. This has proved a highly effective method of carrying out novel interfacial research, allows groups to address more substantial research questions and generates a truly interdisciplinary research capability for further work. Using this project as a case study has provided an insight into the value of this approach and the specific issues to be considered.

Positional characteristics of fluorophores influencing signal output of a DNA nanoswitch

The Holliday junction (HJ) structure, consisting of four DNA double helices with a central branch point, is capable of switching between conformational states upon ion binding. The HJ nanoswitch described here comprises a long, dual labeled cloverleaf oligonucleotide and a short, unlabeled oligonucleotide. Fluorescent labeling with donor and acceptor dyes placed on the HJ arms of the cloverleaf strand allows the ion induced conformational switch to be detected optically using fluorescence resonance energy transfer (FRET). The influence of donor and acceptor dye location on the detection of conformational switching has been investigated using two distinct HJ structures. In addition, the effect of increasing HJ arm length in order to increase donor and acceptor dye separation has been evaluated. We report that a preferential HJ nanoswitch structure can be determined, capable of efficient detection of ion induced conformational switching