Optical sensing platform for real-time detection of zoonotic pathogens

Around 60% of all pathogens infecting humans are shared with non-human vertebrates (i.e. are zoonoses) and, as exemplified by the current COVID pandemic, the vast majority of new and emerging infectious diseases (EID) of humans are zoonotic in origin. Although EID tend to grab the headlines, endemic zoonoses are probably the greatest burden on human health and livelihoods globally, not just in low and middle-income countries but also in the UK, where, for example, zoonotic campylobacteriosis is the most common gastrointestinal infection.
Surveillance and investigation of outbreaks of zoonotic disease are often hampered by the inability to undertake real-time diagnostics either in the living host, in meat or other food products during processing and retail.
This proposal will address the issue of inability to undertake real-time diagnostics by developing a novel, transformative technology based on functionalised optical fibre sensing platform, as a means of identifying zoonotic pathogens in appropriate tissues, all of which could be scalable to routine use. The optical fibre sensor is highly versatile, it is the width of a human hair and can be easily incorporated into a needle probe for easy, rapid and low cost use in the field. By coating the optical fibre with a sensitive material, the light transmitted from one end of the fibre to the other will be affected by the amount of pathogen present. Changing the coating on the fibre enables different pathogens to be detected.
The proposed sensing platform will have a significant positive impact on global scientific, and health and well-being landscapes. Industries and healthcare organisations will be the immediate beneficiaries of campylobacteriosis and coxiellosis testing, which is currently both slow and expensive, and rolling out this technology in the UK would give UK food industries a huge trade advantage internationally. The potential to adapt the technology to other diseases will lead to even greater impact.

Sensing techniques based upon optical fibre devices can be used to probe the optical characteristics of materials that exhibit changes in their optical properties upon exposure to targeted chemical species. The research proposed will develop a novel optical fibre sensor system based on long period gratings (LPGs) modified with appropriate sensitive layers that will measure exemplar analytes Campylobacter spp and C. burnetti.
An LPG is a core-cladding mode coupling device where the in-fibre grating has a period of order 100-500 um. The high attenuation of the cladding modes results in the transmission spectrum of the fibre containing a series of resonance bands centred at discrete wavelengths. An LPG sensor provides wavelength encoded information where the position of the attenuation band in the transmission spectrum depends on the surrounding refractive index and grating period.
Such devices are particularly attractive due to their high sensitivity, selectivity, low cost instrumentation and the prospect for portable measurement in the field. Our group has develop medical devices and diagnostics based on optical fibre sensors, publishing a proof of concept for a diagnostic device based on an LPG optical fibre sensor, modified with gold nanoparticles and anti-IgM - the first demonstration of using this highly sensitive sensor for antibody detection.
In this proposal we will adopt this approach and develop LPG sensors to detect pathogens in human specimens (faeces and blood) and source samples such as poultry meat, waste water, milk and ruminant tissues. Crucially, the approach proposed here can be adapted to detect the range of other key zoonotic pathogens, for example Salmonella spp (genus-specific Salmonella LPS), Avian Influenza (Influenza A neuraminidase), Hantaviruses (hantavirus nucleocapsid protein) and Hepatitis E virus (surface and 'e' antigens).