Biosensor to aid battle against cancer
A nano-sensor that detects biomarkers in urine or saliva samples could detect cancer at the earliest possible stage and save millions of lives.
This is the hope of engineers at Swansea University where work is being conducted to develop a new kind of biosensor made of graphene grown on a silicon carbide substrate using silicon sublimation.
Graphene – discovered in 2004 by physicists at Manchester University – is a one-atom-thick carbon layer that is stronger and possesses greater electrical conductivity than other semiconducting materials such as silicon or gallium arsenide.
Dr Owen Guy, who is leading the research programme at Swansea, said his team will use advanced chemistry to attach ‘bio-receptors’ to nano-channel graphene devices. These receptors will detect the presence of cancer-indicating biomarkers in urine or saliva samples.
Guy said in the early stage of disease certain biomarkers such as 8-hydroxydeoxyguanosine, which is indicative of prostate cancer, are found in low concentration.
Current diagnosis of disease biomarkers is based on detection of fluorescent labelled probe molecules that interact with specific receptors bound to a substrate. Guy said this is expensive and time consuming and lacks the sensitivity needed to pick up lower concentrations of biomarkers.
The Swansea team believes nano-scale electrochemical biosensors can achieve much higher sensitivities, using biomarkers without fluorescent labels.
With prostate cancer, early detection can greatly enhance the chance of survival. The disease is the second most common killer of men in the UK, but there is approximately a better than 70 per cent chance of successful treatment if it is detected early.
Guy is aiming to develop a proof-of-concept hand-held detection device that will incorporate a bio-sensing chip, micro-fluidic system for filtering the liquid bio-sample, a signal receptor and amplifier. The results of the sample test would be read on a digital display on the outside of the device.
Although clinical trials are not likely for at least two years, Guy already sees the technology as a potentially ‘revolutionary’ healthcare solution. In the future he believes these devices could be used for diagnosing and monitoring not only in hospitals and GP offices but also remotely at the point of care. He added that mobile monitoring systems, which transmit a signal to a hand-held readout display, could allow patients to remotely transmit information on conditions such as diabetes to doctors from their own homes.
Dr Kate Holmes, research manager at The Prostate Cancer Charity, backs up Guy’s enthusiasm for the technology’s potential.
’This new technology may be of benefit to the diagnosis of a number of illnesses, but in this study, the researchers have chosen to focus their studies on prostate cancer, to try and tackle the important issue of accurate diagnosis,’ she said.
’If successful, this new test could be of great benefit to men, potentially allowing more accurate testing for prostate cancer to take place in a doctors surgery avoiding the need for further invasive procedures in hospital.’
Holmes added there is an urgent need to improve on the basic tests currently in place to detect the early stages of prostate cancer. ’Currently, the PSA blood test is not a reliable diagnostic marker of the disease and is unable to distinguish cancer from other, non-cancerous prostate problems.
’Very little is currently known about which biomarkers are involved in prostate cancer detection and progression. Around the world, extensive work is being undertaken to identify biomarkers which will enable early diagnosis alongside a more accurate prediction of the aggressiveness of the cancer. It will be critically important to develop these biomarkers and then to apply suitable technologies to enable them to be accurately measured.
’This new nanotechnology offers the potential of facilitating this measurement. A combination of biomarker detection and effective technology would benefit many men who are diagnosed with an early, slow growing prostate cancer to eliminate the risks of unnecessary treatment, and also represent a huge advance in improving early detection of aggressive forms of the disease which require immediate treatment. If this were possible, we could expect to see a significant increase in the survival of men diagnosed with prostate cancer.’
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