A new blood test that can detect early markers of Alzheimer's disease has been developed in UK. The test provides an accurate diagnosis by identifying even small quantities of amyloid-beta clusters- the toxic proteins responsible for Alzheimer's disease- present in the blood stream, and differentiating them from the individual amyloid proteins found in healthy people.

Alzheimer's disease, that leads to the destruction of memory and other important functions of the brain, including thinking, communication and behaviour has been strongly linked to the protein plaques and tangles formed in the brain. The accumulation of cellular waste products including beta-amyloid subsequently damages and kills brain cells, leading to memory problems.

According to Fisher Center for Alzheimer's Research Foundation in the US, the disease strikes every 68 seconds and is one of the most common causes of dementia.

Currently, there hardly exists any test to diagnose the condition. According to experts, a person starts getting clinical symptoms nearly 10 years after the disease starts developing. Doctors diagnose it through symptoms and testing thyroid disorder, vitamin deficiency, brain imaging and neuropsychological factors. The whole procedure takes time to give an accurate diagnosis, thus delaying the treatment and possibility of recovery. Examination of brain after death is the only accurate way presently available to confirm the disease.

The new biosensor, developed by a team of scientists from the University of Leeds in UK, brings hopes as it helps detect the condition early by measuring and identifying the harmful protein clusters formed in the blood. Presence of these toxins in the blood stream has long been linked directly to the level of these protein clusters found in the brain.

"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," Dr Jo Rushworth, who led the study, said in a news release.

"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 biosensor works by producing an electrical signal on detecting amyloid clusters in the blood. To examine effectiveness of the test, researchers grew amyloid clusters, similar to Alzheimer's disease in a test tube. During the experiment, the biosensor correctly identified the amyloid clusters.

Based on their findings, researchers are planning to develop a finger-prick blood test to determine the condition early. "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," Rushworth, explained.

The study has been published in the journal Biosensors and Bioelectronics.

Efforts to develop an effective test that facilitate an early diagnosis of Alzheimer's disease have been going on from a long time. In March last year, a team of researchers from the University of Nottingham in the UK developed a blood test that gives an early diagnosis of Alzheimer's disease by measuring markers in the blood, mainly certain proteins linked to the disease -amyloids and APOE.

In December last year, researchers at the King's College in London announced that they are close to developing a blood test that helps diagnose the condition during the early stages.