Project Outline

This project has two key aims; 1) develop robust tools to explore the glycan binding of snake venoms for diagnostic applications and 2) apply this research in rapid diagnostics for snake envenomation.

Background & Project Outline

Every 5 minutes, 50 people are bitten by a snake worldwide, 4 will be permanently disabled and 1 will die. Snake envenomation is a neglected tropical disease (NTD) that requires urgent attention. Current research has focused on antibody-based solutions, both in diagnostics and treatments. However, this does not need to be the case; other sensing units are possible.

In 2021, Dr. Baker’s research put forward a new sensing unit for lateral flow devices – glycans (sugars), in a lateral flow glycoassay (LFGA) for COVID-19. During the COVID-19 pandemic, Dr Baker explored the glycan binding of SARS-COV-2 (SC2) spike protein using nanoprobes, that mimic the multivalency of glycans on cell surfaces in the glycocalyx. Baker et al. (2020 & 2021) were the first to elucidate the sialic acid glycan binding preference of SARS-COV-2 spike protein. This research was applied by Dr Baker into lateral flow devices used to sense for SARS-COV-2 in patient samples and laid the foundations for others to explore the role of glycan binding in SARS-COV-2 infection. The COVID-19 pandemic highlighted the capabilities and value of point-of-care tests (POCT) such as lateral flow devices. Indeed, it is anticipated that the POCT market will be worth almost $70 billion USD by 2030.

Glycan-protein interactions are fundamental in biology: however, they are difficult to dissect, requiring centralised high-resolution spectroscopy/spectrometry or arrays with labelled (non-native) protein probes. This is exemplified by understudied snake venoms, which are known to contain glycan binding proteins (lectins), in potentially more than 200 species. The role of these lectins is not understood, and their biotechnology potential not deployed.

This project will develop unique glycan probes which can be used with native and un-purified snake venom to identify new lectins, decode their binding capability, and produce a new generation of rapid medical diagnostics for snake envenomation as a neglected tropical disease. There is a pressing need for this research and technology with WHO estimating that snake envenomation (bites) cause ~100,000 deaths a year and approximately three times as many amputations and permanent disabilities.

Key Objectives

1. Study the key components of nanoparticle systems, considering stability and specific binding in aggregation and lateral flow assays.
2. Use the tools developed to explore the glycan binding of diamondback rattlesnake (C. atrox) venom, a venom with well-studied glycan binding.
3. Use the tools developed to explore the glycan binding of D. russelii (Russell’s viper) venom, a venom with known but poorly explored glycan binding.
4. Produce a lateral flow diagnostic for detecting Russell’s viper (D. russelii) venom in blood versus the other members of the “Big Four” (the four species that cause the greatest number of medically significant bites in India and the surrounding countries; Indian cobra - N. naja, common krait – B. caeruleus, Indian saw-scaled viper – E. carinatus)

References

1. Baker, A. N.; Glycan-Based Flow-Through Device for the Detection of SARS-COV-2. ACS Sens 2021, 6 (10), 3696–3705.
2. 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.
3. Baker A.N., Glycosylated Gold Nanoparticles in Point of Care Diagnostics: from Aggregation to Lateral Flow. Chem. Soc. Rev., 2022, 51, 7238-7259
4. Hartweg M.; Synthetic Glycomacromolecules of Defined Valency, Absolute Configuration, and Topology Distinguish between Human Lectins. JACS Au, 2021, 1, 10, 1621-1630

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, mass spectrometry, biolayer interferometry/surface plasmon resonance, x-ray photoelectron spectroscopy and lateral flow/diagnostic design and testing approaches.