Immuno Diagnostix (IDX) - An ultrasensitive, low cost photonic biosensor

Around 400,000 people in the UK live with rheumatoid arthritis (RA). RA is an inflammatory disease that affects the joints, causing swelling, restricted movement and pain. Although there is no cure for RA, there are today a wide variety of treatments that can help reduce inflammation, relieve pain and minimise joint damage. Given the wide number of treatments, how do we know which treatment is the best for each individual patient? Furthermore, the drugs used to treat RA can have detrimental side effects, including cardiovascular disease and a higher susceptibility to infection. It is therefore critical that patients are monitored regularly to check whether their treatments are working and that the side effects of their medication are reduced. At present, this is done using blood tests which are usually performed every month at the hospital. However, the frequency of these tests leads to disruption to patients who are often functionally incapacitated by their disease, and significant costs to the NHS. In the last few years, there has been increasing interest in reducing the number and frequency of patient visits through the introduction of technology that would enable remote monitoring. The advent of the COVID-19 pandemic has accelerated the need for this technology, as telephone or internet-based appointments have become the norm and it is desirable to not have immunocompromised patients attending medical centers for blood tests.
We previously demonstrated a new diagnostic technology that can detect and quantify the proteins in blood that are used to check the efficacy of RA treatments. This diagnostic technology, called a guided mode resonance (GMR) sensor chip, is based on an optical diffraction grating that is rendered sensitive to specific proteins by grafting of antibodies on the sensor surface. Unlike traditional blood tests, our technology only requires very small volumes of blood (just a fingerprick), can be performed by non-specialists, potentially even the patient themselves, and only requires very low cost components. Despite this, the sensitivity of the technology is comparable to the larger, more complicated systems currently used for blood tests in hospitals. To date, this new technology has been shown to work well in trials in our dedicated laboratories. In this project, we will work with industrial partners to develop the technology, involving clinicians specialising in RA and with RA patients themselves, so it can be used to allow blood testing remotely. Specifically, we will design, build and test a small, low-cost instrument that is capable of reading the sensor chip and quantifying the protein concentration. At the same time, we will construct a simple microfluidic device that is capable of accepting a droplet of blood from a fingerprick, delivering the sample to the sensor for analysis and counting the number of white and red blood cells. Finally, we will test the device using blood samples from RA patients and compare our new technology to tests performed in the hospital using established methods.