Scientists at the University of Leeds have developed a new technology that could form the basis of a simple blood test for Alzheimer's disease.
The new biosensor measures harmful clusters of the protein amyloid-beta, an early indicator of Alzheimer's disease. The study is published in the Biosensors and Bioelectronics journal.
Alzheimer's disease is the most common form of dementia, with more than 37 million sufferers worldwide, but currently cannot be conclusively diagnosed until after death.
Dr Jo Rushworth, who led the study by a team in the University of Leeds' Faculty of Biological Sciences, said: "At present, if you go to a doctor, they will do a memory test and they may say you have dementia. They may also say that Alzheimer's is the probable cause, but the only way to definitely find out whether someone had the disease is to examine the brain after death."
Dr Rushworth added: "Because we are relying on symptoms, drugs are given to the patient late. What we need is a reliable early test so we can intervene when it is actually going to be of some use. If we were able to diagnose Alzheimer's disease earlier, the symptoms could be better managed and future treatments could be given at a time when they would have most effect."
The team at the University of Leeds devised a biosensor that can detect very small quantities of amyloid-beta clusters, an early indicator of Alzheimer's disease. The biosensor, which is contained on a small gold chip, generates an electrical signal in the presence of amyloid clusters, the strength of which indicates the number of clusters in the sample.
Previous research had shown that the level of amyloid clusters in a patient's bloodstream correlates with the level of amyloid clusters in the brain, which is linked to Alzheimer's disease onset and severity.
Dr Rushworth said: "Amyloid-beta is a bit like chewing gum; it is very sticky and clumps together in balls. In Alzheimer's disease, you get lots of big sticky balls of amyloid-beta, made up of many individual amyloids, which latch on to brain neurons. This key event triggers disruption of neuronal communication and leads to the eventual death of the neurons.
She added: "Until now, it has been very difficult to pick out these amyloid clusters from the individual amyloid proteins which are present in healthy people. Our biosensor test uses a new molecular recognition tool that works like a lock that only fits one key; it picks out the ball-shaped amyloid clusters without detecting the individual amyloids."
The team at Leeds tested their biosensor on amyloid clusters generated by cells grown in a test tube. The biosensor was able to pick out amyloid clusters similar to those found in human Alzheimer's disease patients.
"We are still at the laboratory stage but, eventually, if we are able to develop this technology, we would be looking to have a mobile phone-sized device where you could do a finger-prick blood test and get an immediate readout telling the doctor the level of these markers in your system."
Biosensors, such as the finger-prick blood sugar monitor used by diabetics, have the advantage of being rapid, easy to handle and can be used in a doctor's surgery or by a patient at home.
As well as speeding up diagnosis, an Alzheimer's biosensor would also allow doctors to distinguish Alzheimer's from other types of dementia and avoid prescribing drugs that are not relevant to a patient's condition.
Dr Simon Ridley, Head of Research at the charity
who provided research funding, said: "A blood test to help diagnose Alzheimer's could be extremely beneficial for patients, but this new technology is still at an early stage of development and further research will be needed to determine its potential for use in the clinic. Diagnosing diseases like Alzheimer's is a challenge and a biosensor for markers of the disease could be a helpful addition to the current methods used. The search for diagnostic markers of Alzheimer's is developing at a rapid pace and investment in research is crucial if we are to explore the true potential of this kind of technology for helping people with dementia."
Dr Jo Rushworth is available for interview.
Images of the biosensor and copies of the paper are available on request.
Contact the University of Leeds Press Office on 07712 389448 or firstname.lastname@example.org
The full paper: Jo V. Rushworth, Asif Ahmed, Heledd H. Griffiths, Niall M. Pollock, Nigel M. Hooper and Paul A. Millner "A label-free electrical impedimetric biosensor for the specific detection of Alzheimer's amyloid-beta oligomers," Biosensors and Bioelectronics (2013) was posted on ScienceDirect on December 24 (URL: http://www.sciencedirect.com/science/article/pii/S095656631300907X; DOI: 10.1016/j.bios.2013.12.036)
Jessica Kwok and Ronaldo Ichiyama, International Spinal Research Trust (Feb 2018), £94,450
Dave Lewis and Colleagues in South Africa, HEFCE Global Challenge Research (Jan 2018), £48,000
Sarah Calaghan, Ed White, John Colyer, Isuru Jayasinghe, BHF (Jan 2018), £128,308
Christine Foyer and Alison Baker, HEFCE GCRF Grant (Jan 2018), £71,158
Alison Baker, Yun Yung Gong and Lindsay Stringer and ICRISAT India, HEFCE GCRF Grant (Jan 2018), £27,000
Graham Askew, Simon Walker, BBSRC (Jan 2018), £699,781
Jennifer Tomlinson, Royal Society (Jan 2018), £512,801
Alison Dunn, NERC (Dec 2017), £18,000
Jennifer Tomlinson, Royal Society-Research Fellows Enhancement Award (Dec 2017), £94,681
Helen Miller, AB AGri Grant (Dec 2017), £73,600
Simon Walker, Royal Society Enhancement Award (Dec 2017), £10,000
Carrie Ferguson, Bryan Taylor, Harry Rossiter, The Physiological Society (Dec 2017), £7,392
Ralf Richter, Royal Society (Dec 2017), £6,000
Christine Foyer, British Council Newton Fund (Dec 2017), £49,840
Adrian Whitehouse and colleagues in School of Chemistry and University of Liverpool, MRC (Nov 2017), £622,319
Michelle Peckham, Neil Ransom, MRC (Nov 2017), £495,159
Dave Lewis, British Council India (Nov 2017), £22,540
Hannah Dugdale, Royal Society (Nov 2017), £15,000
Elton Zeqiraj, Royal Society (Nov 2017), £15,000
Shaunna Burke, Cancer Research UK Innovation Grant (Nov 2017), £20,000
Alex O'Neill and colleagues in Chemistry, BBSRC (Nov 2017), £431,865
Jessica Kwok, Wings for Life (Nov 2017), £87,365
Tom Bennett, BBSRC (Oct 2017), £523,679
Neil Ranson, Darren Tomlinson, BBSRC (Oct 2017), £494,318
Nikita Gamper, BBSRC (Oct 2017), £490,426
Amanda Bretman and colleagues from UEA, NERC (Oct 2017), £430,886
Juan Fontana, Rosetrees Trust consumables grant (Oct 2017), £22,500
Helen Miller, DSM Nutritional Products AG (Sep 2017), £69,988
Neil Ranson, Juan Fontana, Mark Harris, Michelle Peckham, Ralf Richter, Peter Stockley, Patricija Van Oosten-Hawle and colleagues in Engineering, FMH and MAPS, Wellcome Trust Equipment Call (Sep 2017), £418,000
Jamie Johnston, Physiological Society (Sep 2017), £10,000
Frank Sobott, Adrian Goldman, Mark Harris, Andrew Macdonald, Stephen Muench, Sheena Radford and colleagues in FMH and MAPS, Wellcome Trust Equipment Call (Aug 2017), £415,000
Ralf Richter, David Brockwell, Eric Hewitt, Jessica Kwok, Emanuele Paci and MAPS/FMH, BBSRC (Jun 2017), £600,000
Eric Blair, Adrian Whitehouse, Nicola Stonehouse, Alison Baker, Richard Bayliss, Joan Boyes, Ryan Seipke, Sally Boxall and MAPS/FMH, BBSRC (Jun 2017), £376,000
Stefan Kepinski, Yoselin Benitez-Alfonso, Tom Bennett, Michelle Peckham, BBSRC (Jun 2017), £331,000
Roman Tuma, Lars Jeuken, Paul Millner, Sheena Radford, Peter Stockley and MAPS/FMH, BBSRC (Jun 2017), £222,000
Vas Ponnambalam, Darren Tomlinson, Stephen Wheatcroft, BHF (May 2017), £107,878
Graham Askew in collaboration with Bangor University, BBSRC (Mar 2017), £477,383
Stephen Muench, BBSRC (Mar 2017), £132,945
Nic Stonehouse, MRC (Mar 2017), £906,341
Bill Kunin, Steve Sait, BBSRC (Mar 2017), £602,831
Adrian Goldman, EU (Mar 2017), £546,576
Sheena Radford, Wellcome Trust (Mar 2017), £1,836,482
Tom Bennett, Royal Society (Mar 2017), £15,000
Jamie Johnston, Royal Society (Mar 2017), £15,000
Beatrice Filippi, Royal Society (Mar 2017), £15,000