Multiplatform sensors for biogenic amines
The deadline for 2012 Doctoral College Studentships has now passed.
The Brighton Doctoral College is pleased to welcome applications from self-funded or externally sponsored students for programmes of research in this or a closely related area, beginning from September 2012. Applications are welcome from students wishing to study full time or part time, and applications are welcome from students in employment who have the support of their employers.
- Based in the Faculty of Science and Engineering
- Supervisors: Dr Peter J Cragg; Dr Bhavik Patel.
Application deadline
The university cannot guarantee that students can start at their requested date unless deadlines are met.
- UK/EU students: The deadline for the university to receive applications for an entry date of October is the 1 August, for January entry it is the 1 November and for May it is the 1 March.
- International students: The deadline for the university to receive applications for an entry date of October is the 1 June, for January entry it is the 1 September and for May it is the 1 January.
Biogenic amines (BAs) are naturally occurring compounds formed predominantly by microbial biotransformations of amino acids, aldehydes and ketones.
They include the heterocycles histamine, tryptamine, tyramine and phenylethylamine, and the linear polyamines putrescine, cadaverine, spermine and spermidine. These compounds are found in high levels in foodstuffs that involve microbial processing steps, e.g. cheese which contains up to 1 g kg-1 of BAs. Their concentrations are closely linked to the presence of toxic bacteria, particularly in fish decomposition where BA levels can reach 5 g kg-1.
The central problem for the food industry is the lack of a fast, reliable, test for these compounds, with current methods almost universally involving laboratory tests based on chromatographic methods. This project aims to design and synthesise a group of molecular receptors with specific affinities for the key biogenic amines. These molecular receptors will then be incorporated into a number of sensor platforms that are capable of addressing industry requirements. It is envisaged that the studentship would involve developing two classes of sensors:
- The first will use surface modified gold nanoparticles, later to be replaced by more commercially viable silver nanoparticles, to give a colorimetric test for the presence of BAs. This test would be appropriate for on-site use by a non-expert and would give a simple ‘safe/unsafe’ reading.
- The second class of sensors is based on electrochemical methods. The molecular receptors will be incorporated within electrode and micro-electrode matrices for use in a laboratory environment to give accurate concentrations of BAs at, and below, the safe limits. In a parallel development, the molecular receptors will be chemically bound to gold surfaces, using the same well-tried technology used to modify gold nanoparticles, so that other electrochemical detection systems, such as the quartz crystal resonant sensor (QCRS), can be employed. These systems will also give highly accurate responses but have the potential to be used in portable devices.
Extensive electrochemical testing will be used to assess sensitivity, selectivity and limits of detection for a range of biogenic amines. Modified nanoparticles will be investigated by optical and spectroscopic methods. As BAs are produced by numerous common bacteria including Enterobacter sp., Pseudomonas sp., Micrococcus sp. and some Lactobacillus strains, the student will incubate a range of these to monitor the production of BAs directly. An attempt will be made to determine species-dependent profiles for each BA as these may prove to have diagnostic applications in microbial analysis. The ultimate goal of the project is to produce detectors for expert and non-expert staff to assess when unhealthy levels of biogenic amines have accumulated in foodstuffs.
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