In medical emergencies such as stroke, accurate diagnosis as soon as possible following symptom onset is vital to guide critical clinical decisions that will determine the outcome for the patient. Rapid treatment can facilitate perfect recovery. Nevertheless, clinicians lack analytical tools to assist their diagnosis of stroke at these very early stages. Research from Warwick has led to novel biosensors that can measure substances in blood produced from the earliest moments of stroke. These are currently undergoing trials to assess their diagnostic efficacy and how they may transform the stroke treatment pathway and hence patient outcomes.
Stroke is one of the leading causes of death and disability in the UK – in 2010 there were an estimated 150,000 strokes and 50,000 deaths attributable to stroke. Stroke currently costs the UK economy approximately £9bn per year in health and social care costs, including informal care costs, lost productivity and benefit payments. Rapid treatment of ischaemic strokes (to remove the blockage of cerebral circulation) can allow perfect recovery and avoid lasting disability.
On average for every 15 minutes saved in the period from stroke onset to the provision of treatment, one extra month of disability-free life is achieved. As clinical imaging (CT and MRI) is only of limited utility at these very early stages, point-of-care tests that can detect stroke from its earliest moments would help to shorten treatment delays and ensure that as many patients as possible receive treatment.
Professor Nicholas Dale pioneered highly sensitive analytical devices known as microelectrode biosensors, which can be used to monitor in real-time the levels of purines - neurochemicals that influence the function of the nervous system. In 2007 Professor Dale’s lab reported the creation of highly selective biosensors capable of measuring these small metabolites in unprocessed whole blood. By making measurements in blood of patients undergoing carotid artery surgery, during which blood supply to the brain is reduced, Dale and collaborators showed that the purines are indeed a rapidly-produced and sensitive indicator of brain ischaemia.
Most recently, these biosensors have been used to demonstrate that purines are elevated in the blood of stroke patients compared to healthy controls.
The biosensors are currently being developed into a planar array by Sarissa Biomedical Ltd, a spin-out company founded by Professor Dale. These biosensor arrays can measure purines in drops of blood, and make a finger-prick test for ischaemia an attainable vision in the near future. Deployment of this test with paramedics will allow speedier identification of stoke victims at the point of injury, and facilitate rapid coordination of the clinical treatment pathway to maximise the chances of the best possible patient outcomes.
Future work will adapt the underlying biosensor technology for use in other emergency settings where rapid treatment is vital for patient outcome such as foetal hypoxia, diagnosis of trauma and detection of sepsis.