Development of a rapid multiplex Lab on a Chip system for detection of 10 STI pathogens using Biochip Array Technology

Over the past decade the world has seen a significant growth in the prevalence of sexually transmitted infections STIs in the UK for example Syphilis, Chlamydia and Gonorrhoea have shown increases of 1800%, 150% and 42%, respectively, resulting in over 2 million tests being performed in genito-urinary medicine (GUM) clinics across the nation. The availability of a rapid, cost-effective and robust test for the detection of all of these and other STIs, which could be used at the point of care, would not only enhance the delivery of patient care services but would also aid in reducing the further spread of infection. At present no such test exists, with current methodology offering at best duplex target infection assays that fail to meet the sensitivity and specificity of laboratory based tests. The challenge is therefore to develop cost-effective, automated information rich tests that are as accurate as those conducted in the laboratory and that can be used in both primary and secondary care settings. The aim of this project is therefore to realise this unmet challenge through the integration of two existing and complimentary processes (the DNA extraction and PCR amplification chip from Hull and the DNA hybridisation array and chemiluminescence based detector from Randox), to create appropriate technology. The Randox - Hull consortium not only has the technical and engineering capability to develop such technology but also through Randox's commercial presence in the field a clear route to market. Based on recently funded research (EPSRC EP/H007385/1, EP/D040930 and BBSRC BBE0027221), this project will develop a single shot diagnostic chip, which will come pre-loaded with all the necessary reagents and waste containment requirements for it to operate in conjunction with a specifically designed portable low power control and data processing instrument. In practice the user will only need to add a urine or swab sample directly to an adsorbent in a sample introduction chamber on the chip. This level of sample handling and on-chip processing is key in creating technology that will practically reduce both potential exposure to infection and cross contamination between samples when used out of the laboratory environment. Manual closure of the sample chamber will initiate the release of DNA from the sample by mixing with pre-loaded guanidine hydrochloride with the DNA being trapped on a silica monolith from where it will be eluted into a PCR chamber containing pre-loaded reagents. Following amplification the biotin-labelled DNA targets will be transported electrophoretically, to avoid volumetric changes, into the detection chamber where a hybridisation reaction will tether them to an array of specific complimentary nucleotide sequences. Actuators in the control box will then hydrodynamically deliver reagent and wash solutions held on chip to generate a chemiluminescence signal for any positive hybridisation of controls and target analytes present on the array which will be detected using a CCD camera. The chip will be located in a control instrument which will house the required power supplies, pressure actuators, resistively heated air cooled thermocycler and the CCD detector. Software will be developed to control the sequencing and data acquisition of the proposed instrument together with a suitable user interface for presenting information to a clinician prior to them seeing a patient.