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Salisbury, United Kingdom

Sigle D.O.,University of Cambridge | Perkins E.,Dstl Porton Down | Baumberg J.J.,University of Cambridge | Mahajan S.,University of Cambridge
Journal of Physical Chemistry Letters | Year: 2013

Surface-enhanced Raman scattering (SERS) with deep-UV excitation is of particular interest because a large variety of biomolecules such as amino acids exhibit electronic transitions in the UV spectral range and resonant excitation dramatically increases the cross section of the associated vibrational modes. Despite its potential, UV-SERS is still little-explored. We present a novel straightforward scalable route to fabricate aluminum nanovoids for reproducible SERS in the deep-UV without the need of expensive lithographic techniques. We adopt a modified template stripping method utilizing a soluble template and self-assembled polymer spheres to create nanopatterned aluminum films. We observe high surface enhancement of approximately 6 orders of magnitude, with excitation in the deep-UV (244 nm) on structures optimized for this wavelength. This work thus enables sensitive detection of organics and biomolecules, normally nonresonant at visible wavelengths, with deep-UV surface-enhanced resonant Raman scattering on reproducible and scalable substrates. © 2013 American Chemical Society. Source


Harper M.M.,University of Strathclyde | Dougan J.A.,University of Strathclyde | Shand N.C.,Dstl Porton Down | Graham D.,University of Strathclyde | Faulds K.,University of Strathclyde
Analyst | Year: 2012

Developments in specific DNA detection assays have been shown to be increasingly beneficial for molecular diagnostics and biological research. Many approaches use optical spectroscopy as an assay detection method and, owing to the sensitivity and molecular specificity offered, surface enhanced Raman scattering (SERS) spectroscopy has become a competitively exploited technique. This study utilises SERS to demonstrate differences in affinity of dye labelled DNA through differences in electrostatic interactions with silver nanoparticles. Results show clear differences in the SERS intensity obtained from single stranded DNA, double stranded DNA and a free dye label and demonstrate surface attraction is driven through electrostatic charges on the nucleotides and not the SERS dye. It has been further demonstrated that, through optimisation of experimental conditions and careful consideration of sequence composition, a DNA detection method with increased sample discrimination at lower DNA concentrations can be achieved. © 2012 The Royal Society of Chemistry. Source


Biosensors are desired for the detection of a wide range of analytes in various scenarios, for example environmental monitoring for biological threats, from toxins to viruses and bacteria. Ideally a single sensor will be capable of simultaneous multianalyte detection. The varying nature, and in particular disparate size, of such a variety of analytes poses a significant challenge in the development of effective high-confidence instruments. Many existing biosensors employ functionalized flow cells in which spatially defined arrays of surface-immobilized recognition elements, such as antibodies, specifically capture their analyte of interest. To function optimally, arrays should provide equivalent responses for equivalent events across their active area. Experimental data obtained using a grating coupled surface plasmon resonance (GC-SPR) instrument, the BIAcore Flexchip, have revealed differences in response behaviors between proteinaceous and particulate analytes. In particular, the magnitude of responses seen with Bacillus anthracis spores appears to be influenced by shear and gravitational effects while those from soluble proteins are more uniform. We have explored this dependence to understand its fundamental impact on the successful implementation of multianalyte environmental biological detection systems. © Published 2012 by the American Chemical Society. Source


Kirkman E.,Dstl Porton Down | Watts S.,Dstl Porton Down
Journal of the Royal Army Medical Corps | Year: 2014

The Combat Casualty Care research programme is an integrated suite of projects designed to address Defence Medical Services' research needs for casualty care. The programme covers a broad spectrum of topics ranging from the pathophysiological and immunological impact of military relevant injuries to the effects of these disturbances on the response to early treatment. Dstl Porton Down has a long history of studying military injuries and has developed models, both in vivo and physical, to address the research needs. The work is conducted in close collaboration with clinical colleagues at the Royal Centre for Defence Medicine who have direct experience of the clinical issues faced by combat casualties and insights into the potential clinical implications of emerging strategies. This article reviews progress in research areas spanning forward resuscitation, with a particular focus on blast-related injuries, trauma coagulopathy, effects of drugs on the response to haemorrhage and deployed research. A significant 'value added' component has been the underpinning of higher degrees for seconded military clinicians at Dstl Porton Down who have made a valuable contribution to the overall programme. © Crown copyright 2014. Source


Lindsay C.D.,Dstl Porton Down | Griffiths G.D.,Dstl Porton Down
Human and Experimental Toxicology | Year: 2013

Staphylococcal enterotoxin B (SEB) is of concern to military and civilian populations as a bioterrorism threat agent. It is a highly potent toxin produced by Staphylococcus aureus and is stable in storage and under aerosolisation; it is able to produce prolonged highly incapacitating illness at very low-inhaled doses and death at elevated doses. Concerns regarding SEB are compounded by the lack of effective medical countermeasures for mass treatment of affected populations. This article considers the mechanism of action of SEB, the availability of appropriate experimental models for evaluating the efficacy of candidate medical countermeasures with particular reference to the need to realistically model SEB responses in man and the availability of candidate countermeasures (with an emphasis on commercial off-the-shelf options). The proposed in vitro approaches would be in keeping with Dstl's commitment to reduction, refinement and replacement of animal models in biomedical research, particularly in relation to identifying valid alternatives to the use of nonhuman primates in experimental studies. © 2013 The Author(s). Source

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