Biosensor could enable early Alzheimer’s diagnosis

Technology under development by researchers in Spain could help clinicians perform early non-invasive diagnosis of Alzheimer’s disease.

Brain section of a transgenic mouse for AD showing accumulations of amyloid plaques (green) and ferritin (red).

The group at the Universidad Politécnica de Madrid (UPM), has designed a new contrast agent for magnetic resonance imaging (MRI) based on functionalised magnetic nanoparticles that could work as a biomarker for an early diagnosis of this disease.

Alzheimer’s affects around 47 million people worldwide, but diagnostic techniques are currently limited to behavioural and neuropsychiatric evaluations, whilst a definitive diagnosis is only possible by analysing the brain of a patient after their death.

The Madrid group’s work could pave the way for new non-invasive methods that could enable far earlier diagnosis of the condition.

The technique focusses around the detection of iron deposits in the brain, which is one of the tell-tale signs of Alzheimer’s disease.

Whilst MRI techniques are able to detect these deposits, it has hitherto only been possible to detect them when they are present in high concentrations, making it difficult to use the technique for early detection.

The UPM group has developed contrast agents that significantly boost the sensitivity for detecting these accumulations.

In a study on its work – published in  the journal Chemical Neuroscience– the team describes the presence of accumulated iron and the protein that stores iron (ferritin) in a hippocampal area of transgenic mice for Alzheimer’s disease.

These accumulations of iron and ferritin are observed around the amyloid plaques which are characteristics of the disease. This finding helped the group develop a contrast agent for magnetic resonance imaging based on the functionalisation of magnetic particles with an antibody that recognises ferritin.

Leader of the group Dr Milagros Ramos explained: “the accumulation of functionalised nanoparticles in the specific area cause a significant decrease in certain values obtained through magnetic resonance, this indicates that the new contrast agent can be useful in the future for an early and non-invasive diagnosis of this pathology through magnetic resonance”.