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Many diseases are characterised by the presence of specific molecules in body fluids. Searching for these molecules is challenging since there are billions of molecules in a sample and finding that specific one requires very sophisticated processes and equipments. Technicians in well equipped labs use chemical procedures to increase the number of these molecules or associate them to other molecules (like antibodies) that act as chemical searchers. When these “searchers” find their target the resulting chemical reaction results in a change of some properties, like the emission of fluorescence, and this can be detected by a sensor. Here again, sophisticated detection equipment is usually needed.
Researchers at eh Ludwig Maximilian University of Munich are using DNA nanotechnology to create nano-antennas (see their representation in the figure) that can amplify the fluorescence signal. The DNA binds with tiny particles of silver and gold acting as light amplifiers. This allows the detection of specific bacteria and viruses, depending on the antibody used in the test.
According to the researchers in the future a device like a smartphone will be able, using its camera to detect the fluorescence, hence, together with a portable, mass market kit to perform the analyses, to detect the presence of a bacteria/virus. This may not be the final exam, but an important first level screening that in case it turns out a positive result will lead to a further test in a professional lab.
It is just one of several advances that by the end of this decade will support decentralised/tele-diagnoses changing the healthcare landscape.
Dear Professor, does the nano-antenna technology (luminous idea!) also lowers the energy needed to excite the fluorescence?
Many thanks for the answer
According to the article: “Interactions between the nanoparticles and incoming light waves intensify the local electromagnetic fields, and this in turn leads to a massive increase in the amplitude of the fluorescence” the nano-antenna is converting the energy of the the incoming light into fluorescence intensity (amplitude) via the electromagnetic field (the one that is actually intercepted by the nano-antennas). So my take would be that yes, you need less local energy to create luminescence but just because you tap onto the energy provided by incoming light…. No free lunch.