The malfunctioning protein structures that cause diseases such as Alzheimer’s and Parkinson’s can be found using just laser light, a team in Sweden and Poland has discovered. Researchers at Chalmers University of Technology in Sweden and colleagues at the Polish Wroclaw University of Technology discovered the method of distinguishing between aggregations of certain proteins, believed to cause the diseases, from well-functioning ones. When amyloid beta proteins gather in large numbers, they begin to inhibit normal cellular processes. Different proteins create different kinds of amyloids, but they generally have the same structure, the researchers said. This makes them different from the well-functioning proteins in the body, which can now be shown using the multiphoton laser technique. Drawing representing structure of properly functioning protein (left) which is optically invisible to high power laser light, and toxic amyloid (right) responsible for brain diseases that might potentially be cured using lasers in phototherapies, say researchers in Sweden and Poland. Image courtesy Piotr Hanczyc. If the protein aggregates are removed, the disease is, in principle, cured. The problem until now has been in detecting and removing the aggregates. “Nobody has talked about using only light to treat these diseases until now,” said Piotr Hanczyc of Chalmers. “This is a totally new approach and we believe that this might become a breakthrough in the research of diseases such as Alzheimer’s, Parkinson’s and Creutzfeldt-Jakob [also known as the human form of mad cow] disease. We have found a totally new way of discovering these structures using just laser light.” Currently, for both detection and removal, the amyloid protein aggregates are treated with highly toxic and harmful chemicals. With their discovery, the researchers are hopeful that photoacoustic therapy, already used for tomography, may be used to nonsurgically remove the malfunctioning proteins without the need for chemical treatments and without harming surrounding healthy tissue. They caution, however, that advanced multiphoton technologies also bring new kinds of limitations and problems. Because other fibrillar proteins, such as collagen, exhibit second harmonic generation that can interfere with the detection of amyloids, more research is needed regarding the method’s sensitivity and background effects, they said. The work appears in Nature Photonics (doi: 10.1038/NPHOTON.2013.282). For more information, visit: www.chalmers.se/en/