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A machine vision system for improving the productivity of LFD rapid diagnostic test devices S&T1

  • School: School of Science and Technology
  • Study mode(s): Full-time / Part-time
  • Starting: 2022
  • Funding: UK student / EU student (non-UK) / International student (non-EU) / Fully-funded


NTU's Fully-funded PhD Studentship Scheme 2022

Project ID: S&T1

A Lateral Flow Device (LFD) is a rapid and low-cost point-of-care, membrane-based platform for detecting and quantifying analytes in complex liquids in a wide range of applications such as food safety, pregnancy tests, and more recently in the detection of SARS-CoV-2 virus (Hsiao et al. 2021, Biosensors, 11(9), p.295). Despite their increased use and great success, LFDs still face challenges including relatively low sensitivity and reproducibility (recent reviews: Sajid et al, (2015), J. Saudi Chem. Soc,19(6), 689 and Shirshahi et al., (2021), TrAC Trends in Analytical Chemistry, p.116200).

In an LFD, a liquid sample containing the analyte, deposited on a sample pad of a test strip, moves via capillary action through the various sections of the strip on which molecules that interact with the analyte are attached. The detection zone consists of a porous reaction membrane (normally made of Nitrocellulose) on which specific biological components (mostly antigen or antibodies) are immobilised in lines. Measuring and controlling capillary flow speed in the membrane is crucial in improving performance and increasing batch-to-batch reproducibility. Wicking speed depends on the membrane physical and chemical characteristics, such as pore size and distribution, porosity, thickness, and chemical treatment, but is also is affected by other factors such as humidity and temperature. We still lack a full understanding of the underlying processes that determine the flow.

Current industry standards of wicking speed measurements rely on introducing liquid at one end and measuring the time taken to fill a strip of a defined length. Whilst useful, this does not account for the decrease in speed with distance travelled, which makes reliability testing and quality control in the manufacturing process of LFDs difficult.

This is in collaboration with Flexotronix. a contract manufacturing organisation producing next generation of high quality rapid LFD diagnostics tests.

Projects aims:

  • To develop new diagnostic tools for measuring wicking rates in open porous membranes. The tools will use machine vision and automated fluid delivery system to establish a high throughput, autonomous system for measuring wicking speed. This will enhance manufacturing workflow and quality control. The diagnostic tool will be distributed to low and middle income countries, as well as providing a desperately needed industry standard for quality control and increased productivity.
  • To develop a theoretical model of capillary flow through membranes, based on their physical and chemical properties to predict the flow speed, which in turn can inform the optimisation of the membranes.

School strategic research priority

This project aligns with two of the research centres, namely the Imaging Materials and Engineering Centre and the Centre for Health, Ageing and Understanding Disease. In addition, it aligns with two of the NTU strategic themes, namely the Health and Wellbeing and the Medical Technology and Advance Material research themes.

Entry qualifications

For the eligibility criteria, visit our studentship application page.

How to apply

For guidance and to make an application, please visit our studentship application page. The application deadline is Friday 14 January 2022.

Fees and funding

This is part of NTU's 2022 fully-funded PhD Studentship Scheme.

Guidance and support

Download our full applicant guidance notes for more information.

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