Tag Archives: Max Planck Institute for Polymer Research (MPI-P)

“Nano-submarines” for a headache

How did those German scientists miss an opportunity to mention the 1966 movie “Fantastic Voyage” and Raquel Welch (the bombshell of her day)? For anyone not familiar with the movie it, featured a submarine that the scientists entered before being miniaturized and …

Raquel Welch, Stephen Boyd, and Arthur Kennedy in Fantastic Voyage (1966) [It looks like the scientists in thesubmarine are now gazing at some body part or other.]

I’m not sure what part of the body these actors are supposed to be dealing with but perhaps this plot description from the IMDB Fantastic Voyage entry will help a bit,

A scientist is nearly assassinated. In order to save him, a submarine is shrunken to microscopic size and injected into his blood stream with a small crew. Problems arise almost as soon as they enter the bloodstream.

Scientist Jan Benes, who knows the secret to keeping soldiers shrunken for an indefinite period, escapes from behind the Iron Curtain with the help of CIA agent Grant. While being transferred, their motorcade is attacked. Benes strikes his head, causing a blood clot to form in his brain. Grant is ordered to accompany a group of scientists as they are miniaturized. The crew has one hour to get in Benes’s brain, remove the clot and get out. Written by Brian Washington <Sargebri@att.net>

Perhaps they’ve left their submarine to get closer to the clot in the brain?

Now for the latest involving “nano-submarines,” or as these scientists prefer nanocarriers, from a July 19, 2018 news item on Nanowerk,

Scientists at the Mainz University Medical Center and the Max Planck Institute for Polymer Research (MPI-P) have developed a new method to enable miniature drug-filled nanocarriers to dock on to immune cells, which in turn attack tumors. In the future, this may lead to targeted treatment that can largely eliminate damage to healthy tissue.

A July 19, 2018 Johannes Gutenberg Universitaet Mainz press release, which originated the news item, explains further,

In modern medicine, patients receiving medication to treat tumors or for pain therapy are often given drugs that disperse throughout the entire body, even though the section of the organ to be treated may be only small and clearly demarcated. One solution would be to administer drugs that target specific cell types. Such nanocarriers are just what scientists are working to develop. These contain, in a manner of speaking, miniature submarines [emphasis mine] no larger than a thousandth of the diameter of a human hair. Invisible to the naked eye, these nanocarriers are loaded with a pharmacologically-active agent, allowing them to function as concentrated transport containers. The surface of these nanocarriers or drug capsules is specially coated to enable them, for example, to dock on to tissue interspersed with tumor cells. The coating is usually composed of antibodies that act much like address labels to seek out binding sites on the target cells, such as tumor cells or immune cells that attack tumors.

Professor Volker Mailänder and his team from the Department of Dermatology at the University Medical Center of Johannes Gutenberg University Mainz (JGU) have recently developed an ingenious new method of binding antibodies to such drug capsules. “Up to now, we have always had to use elaborate chemical methods to bind these antibodies to nanocapsules,” explained Mailänder. “We have now been able to show that all that you need to do is to combine antibodies and nanocapsules together in an acidified solution.”

In their paper in Nature Nanotechnology, the researchers emphasize that binding nanocapsules and antibodies in this way is almost twice as efficient as chemical bonding in the test tube, significantly improving the targeted transport of drugs. In conditions such as those found in the blood, they also found that chemically coupled antibodies almost completely lost their efficacy, while antibodies that are not chemically attached remained functional.

“The standard method of binding antibodies using complex chemical processes can degrade antibodies or even destroy them, or the nanocarrier in the blood can become rapidly covered with proteins,” explained Professor Katharina Landfester from the Max Planck Institute for Polymer Research. In contrast, the new method, which is based on the physical effect known as adsorption or adhesion, protects the antibodies. This makes the nanocarrier more stable and enables it to distribute the drugs more effectively in the body.

To develop their new method, the researchers combined antibodies and drug transporters in an acidic solution. This led – in contrast to binding at a neutral pH – to more efficient coating of the nanoparticle surface. As the researchers explain, this leaves less room on the nanocarrier for blood proteins that could prevent them from docking to a target cell.

Overall, the researchers are confident that the newly developed method will facilitate and improve the efficiency and applicability of therapy methods based on nanotechnology.

I love this video,

Here’s a link to and a citation for the paper,

Pre-adsorption of antibodies enables targeting of nanocarriers despite a biomolecular corona by Manuel Tonigold, Johanna Simon, Diego Estupiñán, Maria Kokkinopoulou, Jonas Reinholz, Ulrike Kintzel, Anke Kaltbeitzel, Patricia Renz, Matthias P. Domogalla, Kerstin Steinbrink, Ingo Lieberwirth, Daniel Crespy, Katharina Landfester & Volker Mailänder. Nature Nanotechnology (2018) DOI: https://doi.org/10.1038/s41565-018-0171-6 Published 18 June 2018

This paper is behind a paywall.

How does ice melt? Layer by layer!

A Dec. 12, 2016 news item on ScienceDaily announces the answer to a problem scientists have been investigating for over a century but first, here are the questions,

We all know that water melts at 0°C. However, 150 years ago the famous physicist Michael Faraday discovered that at the surface of frozen ice, well below 0°C, a thin film of liquid-like water is present. This thin film makes ice slippery and is crucial for the motion of glaciers.

Since Faraday’s discovery, the properties of this water-like layer have been the research topic of scientists all over the world, which has entailed considerable controversy: at what temperature does the surface become liquid-like? How does the thickness of the layer dependent on temperature? How does the thickness of the layer increases with temperature? Continuously? Stepwise? Experiments to date have generally shown a very thin layer, which continuously grows in thickness up to 45 nm right below the bulk melting point at 0°C. This also illustrates why it has been so challenging to study this layer of liquid-like water on ice: 45 nm is about 1/1000th part of a human hair and is not discernible by eye.

Scientists of the Max Planck Institute for Polymer Research (MPI-P), in a collaboration with researchers from the Netherlands, the USA and Japan, have succeeded to study the properties of this quasi-liquid layer on ice at the molecular level using advanced surface-specific spectroscopy and computer simulations. The results are published in the latest edition of the scientific journal Proceedings of the National Academy of Science (PNAS).

Caption: Ice melts as described in the text layer by layer. Credit: © MPIP

A Dec. 12, 2016 Max Planck Institute for Polymer Research press release (also on EurekAlert), which originated the news item, goes on to answer the questions,

The team of scientists around Ellen Backus, group leader at MPI-P, investigated how the thin liquid layer is formed on ice, how it grows with increasing temperature, and if it is distinguishable from normal liquid water. These studies required well-defined ice crystal surfaces. Therefore much effort was put into creating ~10 cm large single crystals of ice, which could be cut in such a way that the surface structure was precisely known. To investigate whether the surface was solid or liquid, the team made use of the fact that water molecules in the liquid have a weaker interaction with each other compared to water molecules in ice. Using their interfacial spectroscopy, combined with the controlled heating of the ice crystal, the researchers were able to quantify the change in the interaction between water molecules directly at the interface between ice and air.

The experimental results, combined with the simulations, showed that the first molecular layer at the ice surface has already molten at temperatures as low as -38° C (235 K), the lowest temperature the researchers could experimentally investigate. Increasing the temperature to -16° C (257 K), the second layer becomes liquid. Contrary to popular belief, the surface melting of ice is not a continuous process, but occurs in a discontinuous, layer-by-layer fashion.

“A further important question for us was, whether one could distinguish between the properties of the quasi-liquid layer and those of normal water” says Mischa Bonn, co-author of the paper and director at the MPI-P. And indeed, the quasi-liquid layer at -4° C (269 K) shows a different spectroscopic response than supercooled water at the same temperature; in the quasi-liquid layer, the water molecules seem to interact more strongly than in liquid water.

The results are not only important for a fundamental understanding of ice, but also for climate science, where much research takes place on catalytic reactions on ice surfaces, for which the understanding of the ice surface structure is crucial.

Here’s a link to and a citation for the paper,

Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice by M. Alejandra Sánchez, Tanja Kling, Tatsuya Ishiyama, Marc-Jan van Zadel, Patrick J. Bisson, Markus Mezger, Mara N. Jochum, Jenée D. Cyran, Wilbert J. Smit, Huib J. Bakker, Mary Jane Shultz, Akihiro Morita, Davide Donadio, Yuki Nagata, Mischa Bonn, and Ellen H. G. Backus. Proceedings of the National Academy of Science, 2016 DOI: 10.1073/pnas.1612893114 Published online before print December 12, 2016

This paper appears to be open access.