Egyptian Blue is one of the oldest artificially produced color pigments. It adorns for example the crown of the world-famous bust of Nefertiti. But the pigment can do even more. An international research team led by Dr. Sebastian Kruss from the Institute of Physical Chemistry at the University of Göttingen has produced a new nanomaterial based on the Egyptian Blue pigment, which is ideally suited for applications in imaging using near-infrared spectroscopy and microscopy. The results have been published in the journal Nature Communications.

Microscopy and optical imaging are important tools in basic research and biomedicine. They use substances that can release light when excited. These fluorophores are used to stain very small structures in samples and to resolve them in modern microscopes. Most fluorophores glow in the range of light visible to humans. In the adjacent range, the near infrared (NIR) with a wavelength starting at 800 nanometers, the light penetrates even deeper into tissue; disturbing side effects are less frequent. So far, however, there are only a few NIR fluorophores.

The research team has now succeeded in dissolving extremely thin layers from grains of calcium-copper-silicate, also known as Egyptian blue. These nanosheets are 100,000 times thinner than a human hair and fluoresce in the NIR. “We were able to show that even the smallest nanosheets are extremely stable, shine brightly and do not fade,” says Dr. Sebastian Kruss, “making them ideal for optical imaging.

The scientists tested their application for microscopy in animals and plants. For example, they followed the movement of individual nanosheets in order to visualize mechanical processes and the structure of the tissue around cell nuclei in the fruit fly. In addition, they integrated the nanosheets into plants and were able to recognize them even without a microscope, which promises applications in the agricultural industry. “With their commitment to state-of-the-art microscopy methods, new findings in biomedical research can be expected in the future,” says Kruss.

The study involved scientists from the Institute of Physical Chemistry, the 3rd Institute of Physics, the Institute of Developmental Biochemistry and the Institute of Geology as well as the Department of Dermatology, Venereology and Allergology of the University Medical Center Göttingen and the University of California Riverside.

Contact:
Dr. Sebastian Kruss
Georg-August-University Göttingen
Faculty of Chemistry
Institute of Physikal Chemistry
Tammannstr. 6
DE-37077 Göttingen
Tel.: +49(0)551 39-20936
Twitter: @KrussLab
E-Mail: skruss@uni-goettingen.de