At scene of crime DNA characterisation

Forensic science is an important tool in the fight against crime and this proposal will build on cutting edge research to create technology that will revolutionise the way DNA fingerprinting can be used at crime scenes to generate quick and accurate answers where they are urgently needed. Over the past decade DNA fingerprinting, together with the establishment of a national database, has becoming one of the most important forensic tools in the fight against crime, with its unique analytical capability to biometrically profile suspects. At present such analysis is carried out in the laboratory environment which requires samples to be collected from the scene of a crime, and then be transported to a central facility for subsequent analysis. This current practice clearly adds additional transport and storage time which in turn increase costs and adds unwanted delays in analysis times. Therefore the development of field-based methodology could prove to be most valuable in generating more rapid DNA-based intelligence. Such capability will not only allow DNA profiles to be obtained in say less than 30 minutes but the parallel operation of such methodology will allow reasonably large numbers of samples to be run before the crime scene becomes contaminated or corrupted. Whilst the basic analytical methodology required to carry out DNA analysis is well established (i.e. extraction and purification of the DNA from the biological sample, amplification of the target DNA by polymerase chain reaction (PCR) and electrophoretic size separation and fluorescent detection of the DNA fragments) the development of a portable device which integrates these hitherto separate functions is a unique challenge which form the basis of this proposal.In order to achieve true hand-held portability the technology needs to be mechanically and chemically/biochemically robust and have low power requirements for battery-based operation. In this proposed project the combined expertise of the applicants will be focused on generating a prototype instrument that will meet the portability requirements outlined above. The work builds on early encouraging research in which micro fluidic methodology coupled with efficient microwave-based heating has been demonstrated to be suitable for the PCR amplification of DNA samples. The micro fluidic approach, which offers small sample capability (microlitres), has already been shown by number of researchers, including the applicants, to offer a rapid approach to the thermal PCR cyclic process suggesting realistic processing times of around 20 minutes. Following amplification of the target DNA, analysis can effectively be performed using capillary electrophoresis-based separations with fluorescence detection and once again the micro fluidic approach has proved advantageous in offering an efficient and rapid separation process within a few minutes. The prototype developed in this application will be based on an integrated micro fluidics manifold or chip that will enable sample extraction/preconcentration, PCR amplification and DNA fragment separation to be achieved whilst exploiting low power requirements by using manual and electrokinetic fluidic pumping, low power solid state microwave-based heating and low power fluorescent detection. Whilst all of the sample processing stages indicated have been demonstrated separately, it is important to stress that there is a real scientific challenge in bringing them all together in an integrated unit with compatible functions and requirements at each stage. If successful, the product will be an example of novel low-cost but highly functional technology, which will be of immediate benefit in the fight against crime. We know this is not going to be easy but we believe the research team assembled around this proposal can get the job done and break the integration barrier to success that currently exists.