Alzheimer’s Disease International estimates that approximately 50 million people worldwide suffer from dementia.¹ One of the most common forms is Alzheimer’s disease, where the brain is irreversibly damaged by the breakdown of nerve cells, resulting in cognitive and motor impairments. The presence of heavy metals in water may be a risk factor for Alzheimer’s disease. Optical chemosensors could be used to make progress in monitoring water pollution, and thus preventing the neurodegenerative disease. These are being researched in the Nanobiophotonics Research Department at Leibniz IPHT together with the American University in Cairo, Egypt.

Mercury, lead, or arsenic are highly toxic heavy metals that pollute water – with dramatic health consequences. Regular monitoring in order to ensure water quality and possible contamination is therefore required. Optical chemosensors are suitable for checking the levels of toxic metals in water. They are extremely sensitive and capable of detecting low concentrations, even of several toxic metals, quickly and at low cost.

“Such sensors are conceivable, for example, in the form of nanoparticles that change their optical properties in the presence of heavy metals. By modifying their surface and attaching special capture molecules, it would be possible to determine in a short time whether a toxic metal is present in a water sample to be examined. In this case, the metal molecule binds to the capture ­molecule, resulting in a color change of the nanoparticles,” explains Prof. Dr. Wolfgang Fritzsche, head of the ­Nanobiophotonics Research ­Department at Leibniz IPHT. ­Together with Hassan Azzazy, ­Professor of Chemistry at the ­American University in Cairo, who was honored with the Georg Forster Research Award of the Alexander von Humboldt Foundation for his achievements, and who is conducting research at Leibniz IPHT as part of a research stay, he investigates the topic of optical chemosensors.

Prof. Hassan Azzazy is also involved in nanotechnologies, and is working to develop affordable and rapidly deployable diagnostic solutions for his home country. In the Middle East and North Africa (MENA region), in particular, the number of people affected by Alzheimer’s could increase by 400 percent by 2050.² Thanks to optical chemosensors, a valuable contribution can be made to reduce key factors in the development of Alzheimer’s disease.

In collaboration with Prof. Hassan Azzazy, a portable system for on-site detection using a colorimetric assay was developed at Leibniz IPHT. This was successfully demonstrated by the researchers for the DNA-based detection of the bacterium Legionella pneumophila. Infection with this pathogen occurs via contaminated water and can escalate to pneumonia. The solution developed is also based on the use of noble metal nanoparticles, whose color change indicates the presence of the ­bacterial genome.

In the picture:
Prof. Hassan Azzazy from the American University in Cairo is working on developing mobile diagnostic solutions.
©The American University in Cairo

¹ Cf. Statista: Statistics on dementia worldwide

² Cf. Deutsche Welle: Dementia is becoming an increasing challenge in the Middle East and North Africa