Alzheimer’s disease  affects about 17 million people worldwide, causing severe memory and cognitive impairment. This often has a significant effect on patients’ mental health, leading to depression, stress and anxiety. It’s also an expensive disease: the World Health Organization (WHO) estimates it costs $600 billion, making it a global socio-economic problem.

While researchers continue to unravel the mechanisms behind the disease and work out how to tackle it, it’s important that patients get the best possible care. Regular monitoring of the disease is part of this, and we’re working on a way to make this faster, easier and cheaper.

Alzheimer’s disease is caused by high levels of a peptide called beta-amyloid in the brain, which leads to the degeneration of brain cells. Doctors use different types of scans and immunoassays, like MRI and ELISA, to estimate the amount of beta-amyloid in the brain. This gives them an indication of how the disease is progressing. But these scans require big, expensive equipment, and trained professionals. This can be challenging, particularly in developing countries and rural settings.

Beta-amyloid can also be found in lower levels in blood, so it’s a useful biomarker to diagnose and monitor disease progression. There is a test that doctors can use to monitor beta-amyloid in the blood, but it’s not very sensitive and takes a long time. The test, called ELISA, requires relatively big samples and takes six to eight hours to produce a result – this isn’t so helpful if a doctor wants to know a patient’s status immediately.

Research has been undertaken to assess each of the methods available to measure beta-amyloid concentration in brain tissue and in blood. None of the existing tests can be done at the bedside and all need special expertise and large samples. They also take a long time to generate a useful result.

Researchers at the Herbert Wertheim College of Medicine, Florida International University in Miami have developed portable sensors that can help patients by supporting personalized therapeutics. They have developed an electrochemical sensor and tested it to detect cortisol – a stress hormone. They say that it’s far better than the conventional technique, ELISA; as it’s more sensitive and faster.

Using similar technology, they are now working towards something that can detect beta-amyloid. The goal is to develop a test that’s sensitive, small and affordable – one that can measure beta-amyloid in the blood at tiny concentrations in just half an hour.

Click here to read more about the study.

This article originally appeared in Biosensors and Bioelectronics, 80, 2016, Pages 273–287.

Biosensors & Bioelectronics is the principal international journal devoted to research, design, development and application of biosensors andbioelectronics.