Yorkshire Philosophical Society

Event Information

Photonic Biosensing of Alzheimer’s Disease Biomarkers

Dr Steven D. Quinn, Senior Lecturer & ARUK Fellow*, School of Physics, Engineering and Technology, University of York

A major issue facing the diagnosis of dementia is the availability of an accessible, scalable, and sensitive technology. Compelling evidence suggests that the abundance of blood-based biomarkers, including ß-amyloid (Aß) and tau implicated in Alzheimer’s disease, change considerably before clinical symptoms arise. Assessing these biomarkers via a straightforward blood test could facilitate early-stage diagnosis, revolutionise the recruitment of patients into clinical trials, and open a platform for at-home treatment monitoring. Current technologies for biomarker analysis are resource-intensive, rely on cerebrospinal fluid extraction, and are not widely adopted.

In this talk, I will demonstrate the detection of blood-based biomarkers using a next-generation photonic biosensor. Based on the principle of Guided Mode Resonance (GMR) spectroscopy, our technology is a low-cost handheld biosensor capable of real-time, sensitive and parallel readouts of biomarker levels. Our technology outperforms competing modalities, has sensitivity to clinically relevant biomarker concentrations, and opens exciting opportunities for democratizing testing.

*ARUK Fellows undertake research supported by The Alzheimer’s Society.  https://donate.alzheimersresearchuk.org/publicnew/

7pm in the Tempest Anderson Lecture Theatre in the Yorkshire Museum.

Member’s report

Steven Quinn started his lecture by providing some facts and figures regarding Alzheimer’s disease such as the cost for Alzheimer’s and Dementia which is currently 25 billion pounds and set to rise to 47 billion pounds by 2050. In addition, that Alzheimer’s and dementia were the leading cause of death in 2022, considerably more than that of COVID-19. There are a number of risk factors for Alzheimer’s and two recently discovered ones are uncorrected vision and high cholesterol.

The two principal proteins involved in Alzheimer’s are Tau and Amyloid beta (Ab). In Alzheimer’s patients Tau forms tangles inside cells and Ab forms plaques 10 microns across. These proteins come from extracellular vesicles which are emitted from cells. One current approach to diagnosing Alzheimer’s is to use PET scanners. However, this approach is very expensive and there are only a few PET scanners in the country (among other drawbacks). Recent work has shown that Alzheimer’s patients show increased levels of Tau and Ab in the brain and blood, but the proteins are present at levels of ng/mL (equivalent to 1000 grains of sand in an Olympic size swimming pool).

Since new therapies for Alzheimer’s are appearing, it is important to catch the disease early, hence the need for new ways to diagnose Alzheimer’s before cognitive decline sets in. At this point Steven Quinn introduced the technologies that he has been using in the development of a new diagnostic test for Alzheimer’s. Guided Mode Resonance uses tiny grooves cut into a Silicon Nitride on Silicon as a basis for the test. When light is shone at this structure, light at a particular wavelength (at a resonance) is absorbed whereas other wavelengths are reflected without absorption. The wavelength that the resonance occurs at can be modified by the presence of material stuck on to the structure. Hence, antibodies are attached to the structure and the Tau or Ab proteins stick to the antibodies and thus cause a change in the resonance conditions. Dr Quinn went on to describe how a much more sensitive test has been devised using gold nanoparticles and the use of grooves which have a fan like appearance and which can be used to create a plate that can be imaged by a mobile phone camera. Hence the test is very cheap and rapid. In addition, multiple biomarkers can be detected (multiplexing) which should enable identifying Alzheimer’s with greater confidence. The technique clearly offers great hope that early diagnosis of Alzheimer’s will soon be possible.

Steven Quinn will be entering the London Marathon in 2025. If you wish to support him, the link is www.justgiving.com/page/runlabrun

Chris Walker