Near Patient Genetic Testing
Molecular diagnostics involves the analysis of trace quantities of nucleic acids such as DNA. Clinical applications for molecular diagnostics currently include (a) identification of infectious disease pathogens (i.e. virus, fungi or bacteria), (b) identification of mutations associated with various genetic disorders (e.g. cystic fibrosis), and (c) genetic profiling of patients and / or disease tissues to determine the optimal therapeutic strategy. However, due to the combination of equipment, facilities and expertise necessary for molecular diagnostics, it is currently only feasible to perform such analysis in centralised laboratories. Researchers in Tyndall, in collaboration with partners in Ireland and elsewhere in EU, have developed platforms for molecular diagnostics which are compatible with near-patient or point-of-care use.
A number of challenges have to be overcome in order that near-patient molecular diagnostics may become practical, the most important of which is the need for development of suitable technologies to enable the complete analysis process to be implemented in near-patient / point-of care settings such as a GP surgery. The “building blocks” necessary for a functional platform include modules for samples preparation, target biomolecule amplification, detection, signal processing, and data interpretation. This multidisciplinary challenge is being addressed in Tyndall, through the development of integrated genetic analysis systems based on state-of-the-art “lab-on-chip” technologies. Leveraging from the extensive experience available for microfluidic device design, fabrication and testing, together with packaging and systems integration, the platforms under development will be capable of performing genetic analysis from patient samples without user intervention (i.e. automated specimen-to-data solution) in order to minimize the expertise required and to ensure reproducibility. Micro- and nanofluidic technologies are being exploited in combination with novel molecular processes to minimise sample and reagent volumes, so that the platform enables rapid analysis during the patient’s visit, while ensuring that the accuracy of results must be at least as high as those achieved in existing centralised clinical laboratories. The platforms comprise of two parts: an instrument and a disposable cartridge. The instrument exploits state-of-the art components to enable a relatively low cost and a user-friendly interface, the disposable part comprises a cartridge, with all of the required fluidic and electronic functionality, squeezed into a miniaturised “lab-on-a-chip” not much bigger than a credit card. Thus, once a specimen sample is applied to the cartridge, all of the rest of the analysis sample and interpretation of the data will be automated. As such, there is a need for integrated systems combining modules for DNA extraction, amplification and detection from blood specimens, for a simplified “blood-to-data” solution for molecular diagnostics. As part of the research in Tyndall, a novel lab-on-chip PCR device has been developed and demonstrated, which enables direct whole blood DNA amplification. The costs for the materials and reagents required for the disposable lab-on-chip device are currently estimated as <€2. The performance of the device is highly reproducible yielding >200nM PCR product from a 0.3mL blood sample.
Collaborations with national and international experts on clinical aspects (i.e. industry and clinician perspectives) have clarified the required performance characteristics, while collaborations with a range of leading technology research groups have enabled a range of alternative “building blocks” to be evaluated on the platform. Ongoing research is focussed on the development of integrated genetic analysis systems, targeting applications including rapid diagnosis of infectious diseases, and gene expression analysis for pharmacogenetics as an enabling technology for personalised medicine. Given that PCR is regarded as the “gold standard” for molecular diagnostic tests, this technology provides the basis for enabling these tests to be performed away from centralised clinics in near-patient contexts, such as local clinics. This will provide the clinician with the capability to perform a diagnosis to inform a decision on which, if any, treatment is required during a single patient visit