Monitoring for Water Quality

Dr Helen Bridle holds a Royal Academy of Engineering/EPSRC Fellowship, at Heriot-Watt University, investigating the detection of waterborne pathogens. The main focus of her work at present is developing methods, particularly those which offer the potential for automated and/or miniaturised systems, for the detection of protozoan pathogens, like Cryptosporidium and Giardia.

This talk will start by giving an introduction to existing methods and current challenges in the monitoring of waterborne contaminants. Subsequently, the talk will cover the costs and benefits of monitoring as well as future directions. Finally, recent research results will be presented.

One major challenge in detecting waterborne contaminants is the concentration and enrichment of low or numbers of pathogens in large volume water samples. Therefore, the first research project presented in this talk is focussed on sample processing, characterising the interactions of pathogens with filter materials to design more efficient concentration procedures with high recovery rates. Prior to this project only one previous study had considered polymer-protozoa interactions. Using a novel polymer microarray approach, to simultaneously screen over 650 different polymers, Dr Bridle, in collaboration with the Bradley group, has identified polymers which either enhance or prevent the adhesion of protozoan pathogens, both of which have potential filter applications.

Following sample processing, pathogen detection is performed. At present concentrated samples are fluorescently stained and studied under the microscope by highly trained technicians. Dr Bridle will present one ongoing project which looks at replacing the microscopic evaluation with biosensor technology. Prior to the utilisation of immuno-based biosensors, a selection of surface modification protocols, to immobilise pathogen capture antibodies on the sensor surface, were characterised. The experiments aimed to optimise the capture efficiency of sensors and the best protocol has now been applied to cantilever sensors.

Another challenge is the detailed characterisation of pathogens in terms of infectivity, providing accurate information to properly assess public health risk. Dr Bridle will present several ongoing or new projects, looking at different methods of determining both the species and viability of the protozoan pathogen Cryptosporidium. The techniques include Raman spectroscopy, dielectrophoresis and excystation protocols and our projects aim to evaluate and apply these techniques in novel miniaturised formats.