Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at www.rcuk.ac.uk/StudentshipTerminology. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.

High amplitude ultrasound waves propagating through tissue have been recently reported to induce a range of potentially beneficial phenomena, such as rapid tissue heating, increased permeability of cells to large drug molecules (sonoporation) or enhanced activity of drugs. These bioeffects are heavily correlated with the ultrasound-induced nucleation and subsequent excitation of micron-sized bubbles, yielding two types of acoustic cavitation activity: (1) inertial cavitation, which dramatically increases the energy transfer to tissue and can cause rapid heating and mechanical damage, and (2) stable cavitation, whereby bubbles act as micropumps that dramatically enhance the local mixing and transport length scales of drug molecules. In cancer treatment, local heating combined with chemotherpay will render cancer cells more sensitive to treatment, whilst local micropumping of the drug can help overcome delivery problems arising from the highly complex tumour structure. In the context of breaking down blood clots for stroke therapy, cavitation-enhanced mixing will promote delivery of the drug to a site of low blood flow and greatly increase the diffusion of the thombolyic drug across the clot surface.However, the nucleation of cavitating microbubbles and subsequent interaction with cells in biologically relevant media remain poorly understood. The objectives of the proposed research therefore are (i) to investigate the potential of cell- and site-specific cavitation nucleation using commercially available targeted nanoparticles currently being developed for molecular imaging; (ii) to understand and optimize the mechanism by which ultrasound and cavitation can enhance local drug delivery and drug activity across inaccessible interfaces such as tumours or blood clots; (iii) to develop clinically relevant means of monitoring cavitation activity and exploit them for real-time monitoring of drug delivery and (iv) to test the optimized drug delivery and treatment monitoring protocols in a clinically relevant organ model.It is hoped that the proposed resarch will pave the road for widespread clinical uptake of cavitaiton-enhanced targeted drug delivery by ultrasound. Particular advantages of this technique will include the ability to locally enhance drug activity, thus reducing the necessary drug dosages and their side effects, and to monitor therapy in real time. The outcomes of the proposed research are expected to be directly transferable to many other novel therapeutic ultrasound applications, such as non-invasive tissue ablation by High-Intensity Focussed Ultrasound (HIFU), acoustic haemostasis and ultrasound-induced opening of the blood-brain barrier for transcranial drug delivery.

Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at www.rcuk.ac.uk/StudentshipTerminology. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.

In the medical and food sectors it is vitally important to quickly and accurately detect and identify pathogenic or food spoilage bacteria in samples. Molecular methods are showing great promise in this area but there is still a need to obtain the organism as a pure viable entity on a culture medium for further identification or typing and to obtain details of antibiotic susceptibility that may be used by the clinician for effective treatment of infection [1]. Many selective culture media formulations have changed little since their introduction 50 years or more ago with the exception of the introduction of chromogenic substrates to agar media some 15 years ago. The latter are generally in the form of a sugar joined to a chromogen to form a glycoside that is colourless. Hydrolysis of the glycoside by an appropriate enzyme releases the chromogen and a coloured halo appears around the bacterial colony. Glycosidase enzymes are not widespread and some may be restricted to only a few species that grow on a particular selective medium. This allows a presumptive identification of the organism saving the analyst a great deal of time and effort [2]. Different sugars may be added to the same chromogen to alter specificity since only the sugar affects enzyme activity [3]. In this multidisciplinary project the student will be involved in the design, synthesis and analysis of novel derivatives of industrially useful chromogens for bacterial detection. They will use computational methods to predict the visual absorption maxima and hence the colour of novel derivatives of known chromogens, for example by using software programmes such as WinPPP and/or PISYTEM. Chromogens of interest within the project include the reactive dyes such as Black 5 and Orange G. A particular aim of the project will be to develop novel chromogens with colours that complement the existing range of available chromogenic substrates. This will allow a greater multiplicity of chromogenic substrates to be used in media to separate organisms in mixtures that are difficult to separate on the presence or absence of one or two particular enzymes. A further aim will be to extend the range of sugars linked to chromogens to determine if glycosides not currently commercially available are useful for the differention of bacterial species. Glycosides will be synthesised using organic chemistry techniques and the student will be trained to perform both large and small scale reactions, and also to handle air sensitive materials. The development of some new methodology will be required. Materials will be purified using a range of techniques such as chromotography and recrystallisation. Glycoside products will then be characterised using state of the art analytical chemistry techniques, such as NMR and UV-Vis spectroscopy, and mass spectrometry. Biological analysis will then be performed to determine the ability of specific glycosidase enzymes to release the chromogen from the substrates, to afford coloured precipitates. Studies using whole bacteria present within food and clinical samples will then be performed to determine whether the substrates do indeed allow identification of particular bacteria, based on specific glycosidase enzymes that they contain. Due to the stringent specificity of glycosidase enzymes, it is essential that individual isomers (anomers) of the targets are prepared for the biological results to be meaningful. Relevant synthetic expertise in both carbohydrate chemistry and prodrug therapy within Professor Osborn's group will ensure that pure individual isomers will indeed be prepared. This synthetic expertise will be complemented by that within Dr Bovill's group, which specialises in the analysis and inhibition of growth of food borne pathogens. [1] Orenga, S. et al., J. Microbiol. Methods, 2009, in press [2] Kiernan, J.A. Biotech. Histochem., 2007, 82, 73 [3] Butterworth, L.A. et al., J. Appl. Microbiol., 2004, 96, 170

With the modern climate of the 'super bugs', for example MRSA, and the ever-increasing resistance of bacteria to many of the traditional antibacterial treatments that are available, it is becoming more and more evident that new initiatives are needed to find alternative methods to treat bacterial infections. Although many approaches have been reported that make significant strides in this area, the ideal antibiotic remains elusive and further research is essential [1]. One of the strategies in the hunt for new treatments is to develop alternative and more effective uptake and release systems for delivering antibiotics to bacteria [2]. In this programme we propose to prepare a wide range of novel glycoside or peptide derivatives of existing antibiotics for the treatment of a range of bacterial infections of clinical importance. Antibiotics studied will be those that have shown promising antibacterial profiles in early studies, but whose full utility has not been fully exploited, for example due to their poor water solubility, or poor bacterial uptake properties [3]. In addition, the utility of the antibacterial agents developed to selectively recover pathogens from food or clinical samples that would normally be overgrown by the background flora will be explored. This will provide selective isolation media that do not suffer from the toxicity problems of existing media. In our approach it is hypothesised that linking the antibiotic to carbohydrates or peptides will produce water soluble agents that are actively taken into the bacterial cell via a carbohydrate or peptide permease uptake mechanism [4]. The agents themselves will be non-toxic to bacteria but once inside the cell, enzymes will selectively release the active antibiotic via hydrolysis of the glycoside or peptide linkage. Since different bacteria contain different glycosidase and peptidase enzymes it is envisaged that selective treatment can be effectively delivered by careful tailoring of the appropriate glycoside/peptide to the bacteria of interest. Once specific isomers have been prepared using current organic synthesis methods, biological analysis and bacteriological testing against a range of organisms will be performed. Thus, the student will have an opportunity to investigate the toxicity profiles of the derivatives in a range of cells using cell culture techniques, and will perform computational and physicochemical studies to determine the physicochemical parameters, stability and 'drug-like nature' of the materials of interest. Bacteriological testing to determine the specificity of action of the agents will include media development; exploring variations of amino acids, sugars, vitamins and other growth additives and enzyme inducers to achieve good growth of test organisms and optimum inhibition and selectivity. This project will provide training in a wide range of techniques including organic synthesis, carbohydrate chemistry, purification techniques and analytical chemistry. This will be coupled with the development of complementary skills to assess the antibacterial properties of the compounds, using enzymatic studies, HPLC, bacteriological testing and the development of appropriate media to support the growth of a range of bacteria. In addition, mathematical and computational expertise will be developed. [1] Su, Z. D., et al., Curr. Opin. Invest. Drugs, 2007, 8, 140 [2] Alanis, A. J., Archive. Med. Res, 2005, 36, 697 [3] Falagas, M.E., et al., Exp. Rev. Anti-infect. Ther., 2008, 6, 593 [4] Conners, S. B., et al., J. Bacteriol, 2005, 187, 7267