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Dataset supporting the University of Southampton Doctoral Thesis "Rapid point-of-care testing solutions to meet clinical needs"
No full textDataset supporting the University of Southampton Doctoral Thesis "Rapid point-of-care testing solutions to meet clinical needs".
Dataset consists of Graphpad Prism files and jpg files
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Rapid point-of-care testing solutions to meet clinical needs
No full textThere is increasing demand for point-of-care testing solutions for both the diagnosis and monitoring of diseases. As has been demonstrated during the pandemic, paper-based lateral flow devices are an excellent candidate for rapid and large population testing providing a binary yes or no answer for the presence of a single covid-specific biomarker. For these devices to be most effective and more widely applicable they instead require to be quantitative and deliver multiplexing capabilities, i.e., be able to measure simultaneously more than one disease biomarker. In this thesis the focus is on the inclusion of the above capabilities into create the next generation of lateral flow devices (LFDs) for wider clinical applications. Using the laser-based direct-write (LDW) technique that implements polymerisation of a photopolymer to produce impermeable barriers within the porous membranes inside a LFD I have demonstrated the use of multiple parallel channels for multiplexed detection whilst removing issues such as cross reactivity and the requirement for tests with larger footprints that ensue a higher cost. This multiple channel flow architecture was also utilised to add semi-quantitative measurement capabilities to the LFD. Further the thesis also explored the use of passive flow control within the LFDs enabled via precise laser-patterning of flow constrictions. The constrictions generate a delay in the flow at given points along the LFD and assist in enhancing their detection capabilities, i.e., their sensitivity. These techniques were applied to demonstrate a multiplexed screening test for Tuberculosis that meets real world requirements. This thesis presents a rapid detection of blood-based biomarkers: CRP, SAA1, LBP and CFHR5 with a multiplexed lateral flow test that has the capability to distinguish those patients with TB from healthy controls with significant accuracy. The diagnostic competence expressed in the form of area under the curve (AUC) was 0.92 for the best two biomarkers and its sensitivity and specificity meets the WHO guidelines for a TB rule-out screening test. Tuberculosis was responsible for 10 million cases globally in 2019 and despite huge efforts the numbers are still increasing
Data in support of the article 'Optimization of flow path parameters for enhanced sensitivity lateral flow devices'
No full textDataset to support the article "Optimization of flow path parameters for enhanced sensitivity lateral flow devices" published in Talanta
Published manuscript dataset</span
Laser-patterned lateral-flow devices with multiple flow-paths for semi-quantitative measurement of the inflammatory biomarker, C-reactive protein
No full textLaser-patterned paper-based flow-through filters and lateral flow immunoassays to enable the detection of C-reactive protein
No full textWe report the use of a laser-based fabrication process in the creation of paper-based flow-through filters that when combined with a traditional lateral flow immunoassay provide an alternative pathway for the detection of a pre-determined analyte over a wide concentration range. The laser-patterned approach was used to create polymeric structures that alter the porosity of the paper to produce porous flow-through filters, with controllable levels of porosity. When located on the top of the front end of a lateral flow immunoassay the flow-through filters were shown to block particles (of known sizes of 200 nm, 500 nm, 1000 nm and 3000 nm) that exceed the effective pore size of the filter while allowing smaller particles to flow through onto a lateral flow immunoassay. The analyte detection is based on the use of a size-exclusive filter that retains a complex (~3 µm in size) formed by the binding of the target analyte with two antibodies each of which is tagged with different-sized labels (40 nm Au nanoparticles and 3 µm latex beads), and which is larger than the effective pore size of the filter. This method was tested for the detection of C-reactive protein in a broad concentration range from 10 ng/ml to 100,000 ng/ml with a limit-of-detection found at 13 ng/ml and unlike other reported methods used for analyte detection, with this technique we are able to counter the Hook effect which is a limiting factor in many lateral flow immunoassays
Optimisation of flow path parameters for enhanced sensitivity lateral flow
No full textLateral flow devices (LFDs) are widely used point-of-care (POC) diagnostics. The basic LFD design remains largely unchanged since their first development and this limits their use in clinical applications due to lack of sensitivity. To enhance this, we report the use of laser-patterned geometric control barriers, in the form of a constriction, that leads to a slower flow rate and smaller test zone area. This high sensitivity LFD (HS-LFD) achieved 62% increase in test line colour intensity for the detection of procalcitonin (PCT) and reduced the LOD from 10 ng/ml to 1 ng/ml with contrived human samples
Capillary-based reverse transcriptase loop-mediated isothermal amplification for cost-effective and rapid point-of-care COVID-19 testing
No full textAs the SARS-CoV-2 pandemic continues to spread, the necessity for rapid, easy diagnostic capabilities could never have been more crucial. With this aim in mind, we have developed a cost-effective and time-saving testing methodology/strategy that implements a sensitive reverse transcriptase loop-mediated amplification (RT-LAMP) assay within narrow, commercially available and cheap, glass capillaries for detection of the SARS-CoV-2 viral RNA. The methodology is compatible with widely used laboratory-based molecular testing protocols and currently available infrastructure. It employs a simple rapid extraction protocol that lyses the virus, releasing sufficient genetic material for amplification. This extracted viral RNA is then amplified using a SARS-CoV-2 RT-LAMP kit, at a constant temperature and the resulting amplified product produces a colour change which can be visually interpreted. This testing protocol, in conjunction with the RT-LAMP assay, has a sensitivity of ∼100 viral copies per reaction of a sample and provides results in a little over 30 min. As the assay is carried out in a water bath, commonly available within most testing laboratories, it eliminates the need for specialised instruments and associated skills. In addition, our testing pathway requires a significantly reduced quantity of reagents per test while providing comparable sensitivity and specificity to the RT-LAMP kit used in this study. While the conventional technique requires 25 μl of reagent, our test only utilises less than half the quantity (10 μl). Thus, with its minimalistic approach, this capillary-based assay could be a promising alternative to the conventional testing, owing to the fact that it can be performed in resource-limited settings, using readily available apparatus, and has the potential of increasing the overall testing capacity, while also reducing the burden on supply chains for mass testing
Optimization of flow path parameters for enhanced sensitivity lateral flow devices
No full textLateral flow devices (LFDs) or lateral flow tests (LFTs) are one of the most widely used biosensor platforms for point-of-care (POC) diagnostics. The basic LFD design has remained largely unchanged since its first appearance, and this has limited LFD use in clinical applications due to a general lack of analytical sensitivity. We report here a comprehensive study of the use of laser-patterned geometric control barriers that influence the flow dynamics within an LFD, with the specific aim of enhancing LFD sensitivity and lowering the limit of detection (LOD). This control of sample flow produces an increase in the time available for optimizing the binding kinetics of the implemented assay. The geometric modification to the flow path is in the form of a constriction that is produced by depositing a photo-sensitive polymer onto the nitrocellulose membrane which when polymerized, creates impermeable barrier walls through the depth of the membrane. Both the position of the constriction within the flow path and the number of constrictions allow for an increase in the sensitivity because of a slower overall flow rate within the test and a larger volume of sample per unit width of the test line. For these high sensitivity LFDs (HS-LFD), through optimization of the constriction position and addition of a second constriction we attained a 62% increase in test line color intensity for the detection of procalcitonin (PCT) and were also able to lower the LOD from 10 ng/mL to 1 ng/mL. In addition, of relevance for future commercial exploitation, this also significantly decreases the antibody consumption per device leading to reduced costs for test production. We have further tested our HS-LFD with contrived human samples, validating its application for future clinical use
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