Browsing by Author "Warwick, Christopher"

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    An assessment of the suitability of using streptavidin coated microspheres on the test line of a lateral flow immunoassay with a hydrophilic membrane
    (Cranfield University, 2008-09) Warwick, Christopher; Taylor, J.
    Lateral flow immunoassays provide quick, qualitative detection of biomolecules. They are designed to be easy to use, cheap and suitable for applications away from the laboratory. Most lateral flow assays detect a single analyte and use two analyte specific antibodies. One antibody is labelled, and physically separated from the other, which is bound to the test line of a hydrophobic membrane. When a liquid sample is applied, the sample and labelled antibodies flow towards the capture antibodies on the test line. If the analyte is present in the sample, a sandwich assay forms on the test line, giving a visual signal to indicate the presence of the analyte. This research investigated using Streptavidin coated microspheres on the test line of a hydrophilic membrane and a mobile, analyte specific, biotinylated capture antibody upstream of the test line. A hydrophilic membrane material reduced the number of materials required, compared to a traditional design and the Streptavidin provided a method for designing a multi-analyte assay with an analyte independent test line. The mobile biotinylated capture antibody and Streptavidin based test line gave variable results. Only one in four of the target assays developed could detect the analyte used (Rotavirus antigen) and only at higher concentrations, compared to traditional lateral flow designs. Better results were achieved by pre-incubating the biotinylated capture antibody with the Streptavidin microspheres, although it was unable to match the sensitivity of the traditional lateral flow assays. Furthermore, traditional lateral flow designs produced obvious results within ten minutes, while hydrophilic membrane based assays, with Streptavidin test lines, took approximately sixty minutes to produce less distinct signals. Experiments were performed to reduce the time taken to generate signals, but no significant improvement was achieved. Further work should investigate the antibodies, buffers, choice of label, alternative test line capture methods and membrane materials.
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    A molecular imprinted polymer based sensor for measuring phosphate in wastewater samples
    (IWA Publishing, 2014-01-31) Warwick, Christopher; Guerreiro, Antonio R.; Wood, Elizabeth; Kitson, James; Robinson, James; Soares, Ana
    Phosphate detection in water samples is still completed using colorimetric standard methods, which have a number of disadvantages, to such as being time consuming, requiring filtration, a number of different reagents, frequent calibration and proper disposal of waste chemicals generated. Hence, a simple cost effective analytical method and instrumentation is highly desirable to aid the optimisation of treatment processes and assist the water industry in their efforts to comply with stringent regulations such as the EU's Water Framework Directive. A sensor based on molecular imprinted polymer (MIP) and a conductance transducer was developed for direct and label-free detection of phosphate in water. The sensor was able to measure the presence of phosphate in wastewater samples with good reproducibility, a linear range of 0.66-8 mg P L-1 and a lower detection limit of 0.16 mg P L-1. The sensor was further tested to measure phosphate concentrations in unfiltered field samples such as domestic wastewater treatment influent and river water and demonstrated a close correlation with reference measurements. The phosphate MIP sensor offers a way forward as either a handheld sensor for use in the field, or as a potential solution for remote, continuous monitoring of phosphate,