Project Outline

The aim of this project is to develop a new hybrid diagnostic approach that allows for the rapid analysis of lateral flow devices (LFDs) by mass spectrometers. This will involve designing LFDs that can isolate from medically relevant media, e.g., blood and saliva, a target viral/bacterial analyte for detection by mass spectrometry without further purification.

Background & Project Outline

Due to the COVID-19 pandemic, diagnostics have been rapidly rolled out globally, with rRT-PCR (real-time reverse transcription-polymerase chain reaction) being the gold standard but turn-around time can be a limiting factor. In July 2020, in the United States, the average wait time for a COVID-19 RT-PCR test was 4 days, and only 37% of people received results within 2 days. A comparison of rRT-PCR to LFDs (Lateral flow devices) showed that LFD sensitivity was 85% and its specificity 95%, with a run time of just 15 minutes, far faster than RT-PCR.

LFDs can provide the combination of low-cost, and robustness required for point-of-care testing (POCT). Furthermore, the POCT market is estimated to be worth ~$70 billion USD by 2030. However, LFDs do have their drawbacks, they are less sensitive than lab-based RT-PCR.

This project aims to overcome the sensitivity problems of LFDs and the slow turn-around time of RT-PCR by coupling lateral flow testing to mass spectrometry – a highly sensitive analytical technique using the highly parallelised and rapid MALDI ionisation methodologies which will also keep the net per-analysis costs very low.

This exciting project will involve multidisciplinary aspects from biochemistry, nanomaterials synthesis, polymer science and analytical chemistry to deliver a novel diagnostic approach ready for the next pandemic. The project will be based in both the Baker Humanitarian Chemistry Group (BHCG) that specialises in developing lateral flow-based diagnostic techniques and the Peter O’Connor group that specialises in mass spectrometry.

The BHCG has previously developed novel lateral flow devices that sense for COVID-19 in patient samples in under 30 minutes. These devices used synthetic glycopolymers rather than antibodies to sense for the target analyte. The O’Connor group has developed a wide range of mass spectrometry approaches that are consistent with LFD technologies including use of MALDI mass spectrometry for detection of analytes directly desorbed from amorphous surfaces. It is also credible to elute the LFD separated materials and analyse them using electrospray (ESI) mass spectrometry, but MALDI is more consistent with high throughput assays and already exists in clinical diagnostic laboratories in most hospitals as the Biotyper instrument.

Vital to this approach is how glycans (sugars) act as anchors for viruses, bacteria, and toxins to bind hosts early in infections. By understanding pathogen/glycan binding we aim to mimic these structures on nanomaterial surfaces to generate sensing components in our diagnostics. These have broad applicability across animal health (both domestic and agricultural), bioterrorism (e.g ricin detection), sanitation (cholera detection) and more.

Key Objectives

• Explore LFD technology, notably the glyco-assay systems developed by BHCG, to elucidate glycan binding of a variety of biological targets (viruses, bacteria, venoms etc)
• Design paper-based and microfluidic systems to purify target analytes from blood and saliva.
• Couple lateral flow technology to MALDI and ESI mass spectrometry techniques.
• Demonstrate the first lateral flow linked mass spectrometry diagnostic

References

1. Baker, A. N.; The SARS-COV-2 Spike Protein Binds Sialic Acids and Enables Rapid Detection in a Lateral Flow Point of Care Diagnostic Device. ACS Cent Sci 2020, 6 (11), 2046–2052.
2. O'Connor, P. B., A high pressure matrix-assisted laser desorption ion source for Fourier transform mass spectrometry designed to accommodate large targets with diverse surfaces. J. Am. Soc. Mass. Spectrom. 2004, 15 (1), 128-132.

Techniques

Organic synthesis and techniques, RAFT polymer synthesis and techniques, GPC/SEC, NMR (1H, 13C, 19F, 2D approaches), FTIR, UV-vis (including aggregation assays for studying binding), dynamic light scattering, MALDI and Electrospray mass spectrometry on ToF, timsTOF, and solariX FTICR mass spectrometers, biolayer interferometry/surface plasmon resonance, x-ray photoelectron spectroscopy and lateral flow/diagnostic design and testing approaches. Expertise in these techniques falls across both the Baker Humanitarian Chemistry Group and Peter O’Connor laboratory.