To fear or not to fear? Nanoplastics, electron microscopy image, colored, 150.000x. Empa / ETH

The images leave no one cold: giant vortices of floating plastic trash in the world's oceans with sometimes devastating consequences for their inhabitants – the sobering legacy of our modern lifestyle. Weathering and degradation processes produce countless tiny particles that can now be detected in virtually all ecosystems. But how dangerous are the smallest of them, so-called nanoplastics? Are they a ticking time bomb, as alarming media reports suggest? In the latest issue of the journal Nature Nanotechnology, a team from Empa and ETH Zurich examines the state of current knowledge – or lack thereof – and points out how these important questions should be addressed.

A comparison of different light microscopy techniques: STED (bottom left) improves the sharpness of detail drastically compared to conventional confocal microscopy (top left). MINSTED (right) achieves a resolution that is yet ten times higher. © Michael Weber / Max Planck Institute for Biophysical Chemistry

Scientists working with Stefan Hell at the Max Planck Institute (MPI) for Biophysical Chemistry in Göttingen and the Heidelberg-based MPI for Medical Research have developed another light microscopy method, called MINSTED, which resolves fluorescently labeled details with molecular sharpness. With MINSTED, Nobel laureate Hell has come full circle. “A good 20 years ago, we fundamentally broke the diffraction resolution limit of fluorescence microscopy with STED. Until then, that was considered impossible,” says Hell. “Back then we dreamed: With STED we want to become so good that one day we will be able to separate individual molecules that are only a few nanometers apart. Now we've succeeded.” At that time, the STED principle amounted to a revolution in light microscopy. For this conceptual leap and subsequent developments, Hell received the Nobel Prize in Chemistry in 2014.

The phantom used for hyperpolarized imaging, with an illustration of imaging slices acquired using the new technique. photo/©: Laurynas Dagys, University of Southampton

New technique using nuclear spin hyperpolarization of hydrogen paves the way for further advances in the field of MRI. Magnetic resonance imaging (MRI) is already widely used in medicine for diagnostic purposes. Hyperpolarized MRI is a more recent development and its research and application potential has yet to be fully explored. Researchers at Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM) have now unveiled a new technique for observing metabolic processes in the body. Their singlet-contrast MRI method employs easily-produced parahydrogen to track biochemical processes in real time. The results of their work have been published in Angewandte Chemie International Edition and chosen by the editors as a "hot paper", i.e., an important publication in a rapidly-developing and highly significant field.

Magnetosomes isolated from magnetic bacteria.

Magnetic nanoparticles biosynthesized by bacteria might soon play an important role in biomedicine and biotechnology. Researchers of the University of Bayreuth have now developed and optimised a process for the isolation and purification of these particles from bacterial cells. In initial tests, magnetosomes showed good biocompatibility when incubated with human cell lines. The results presented in the journal "Acta Biomaterialia" are therefore a promising step towards the biomedical use of magnetosomes in diagnostic imaging techniques or as carrier in magnetic drug delivery applications.