Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Self-disposing supramolecular materials with a tunable lifetime

19.07.2017

Materials that assemble themselves and then simply disappear at the end of their lifetime are quite common in nature. Researchers at the Technical University Munich (TUM) have now successfully developed supramolecular materials that disintegrate at a predetermined time – a feature that could be used in numerous applications.

Plastic bottles, empty cans, old toys, torn T-shirts and worn-out mobile phones – day for day, mankind produces millions of tons of waste. How can we prevent our planet from stifling in the garbage?


With the peptide-synthesizer Dr. Marta Tena-Solsona produces the building blocks for the gels she investigates.

Photo: Uli Benz / TUM


Temporary hydrogels formed by Fmoc-tripeptides.

Image: Benedikt Rieß / TUM

To this day, recycling is the method of choice. But it is expensive: "So far, most man-made substances are chemically very stable: to decompose them back into their components, one has to spend a lot of energy," explains Job Boekhoven, professor of Supramolecular Chemistry at the TUM. Inspired by biological processes the chemist is pursuing another path.

"Nature does not produce garbage dumps. Instead, biological cells are constantly synthesizing new molecules from recycled ones. Some of these molecules assemble into larger structures, so-called supramolecular assemblies that form the structural components of the cell. This dynamic ensemble inspired us to develop materials that dispose of themselves when they are no longer needed. "

Nature as a model

One of the key differences between man-made substances and most living biological materials is their energy management: man-made materials are in equilibrium with their environment. That means that they don’t exchange molecules and energy, thus remaining the way they are.

Nature works according to another principle: Living biological materials, like skin and bone, but also cells, are not in equilibrium with their environment. A constant input of energy and building blocks is necessary for their construction, maintenance and repair.

“A typical example of an energy source is adenosine triphosphate, ATP for short," explains Boekhoven. "As long as enough energy is available, damaged components and entire cells can be broken down and replaced by new ones, otherwise the organism dies and disintegrates into its basic building blocks."

In the end there is just molecular dust

The new materials Boekhoven explored with an interdisciplinary team of chemists, physicists, and engineers at the TU Munich are based on the natural model: the molecular building blocks are initially freely mobile, but if energy is added in the form of high-energy molecules, supramolecular structures form.

These autonomously disintegrate once the energy is exhausted. Thus, the lifetime can be predefined by the amount of “fuel” added. In the laboratory, the materials can be set to autonomously degrade after several minutes to several hours. Moreover, following a cycle, the degraded material can be reused by simply adding another batch of high-energy molecules.

From lab to practice

The scientists designed different anhydrides which assemble into colloids, supramolecular hydrogels or inks. In these materials a chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide as “fuel“. Because of their metastable character, the anhydrides hydrolyze to their original dicarboxylates with half-lives in the range of seconds to several minutes.

Because the molecules form very different structures depending on their chemical composition, numerous application possibilities arise. Spherical colloids, for example, can be loaded with water-insoluble molecules – these could be used to transport drugs against cancer directly to the tumor cell. At the end of their mission, the colloids would autonomously dissolve, thereby releasing the drugs locally.

Other building blocks assemble into long fibrous structures that transform fluids into gels and might be used to stabilize freshly transplanted tissue for a predefined time, after which the body would take over this function. And, inks with precisely defined durability could be produced from molecules that assemble into star-shaped assemblies.

Will it be possible to build supramolecular machines or mobile phones that simply disappear when they are no longer needed? “This might not be completely impossible,” stresses Boekhoven, "but there is still a long way to go. Right now we are working on the basics."

The work was funded by the German Research Foundation via the ATUMS Graduate Program (Alberta / TUM International Graduate School for Functional Hybrid Materials), Collaborative Research Centre SFB863 (Forces in Biomolecular Systems) and the Cluster of Excellence Nanosystems Initiative Munich (NIM), as well as the TUM Institute for Advanced Study which is funded by the German Excellence Initiative and the European Union Seventh Framework Program.

Publication:

Far-from-equilibrium supramolecular materials with a tunable lifetime
Marta Tena-Solsona, Benedikt Rieß, Raphael K. Grötsch, Franziska C. Löhrer, Caren Wanzke, Benjamin Käsdorf, Andreas R. Bausch, Peter Müller-Buschbaum, Oliver Lieleg, Job Boekhoven
Nature Communications, 8, 15895, 2017 – DOI: 10.1038/ncomms15895

Contact:

Prof. Dr. Job Boekhoven
Technical University of Munich
Lichtenbergstr. 4, 85748 Garching, Germany
Tel.: +49 89 289 54400 – e-mail: job.boekhoven@tum.de – web: http://www.supra.ch.tum.de/

Weitere Informationen:

https://www.tum.de/en/about-tum/news/press-releases/detail/article/34080/ Link to the press release

Dr. Ulrich Marsch | Technische Universität München

More articles from Materials Sciences:

nachricht Nanocrystal 'factory' could revolutionize quantum dot manufacturing
18.03.2019 | North Carolina State University

nachricht Design and validation of world-class multilayered thermal emitter using machine learning
15.03.2019 | National Institute for Materials Science, Japan

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

Im Focus: A thermo-sensor for magnetic bits

New concept for energy-efficient data processing technology

Scientists of the Department of Physics at the University of Hamburg, Germany, detected the magnetic states of atoms on a surface using only heat. The...

Im Focus: The moiré patterns of three layers change the electronic properties of graphene

Combining an atomically thin graphene and a boron nitride layer at a slightly rotated angle changes their electrical properties. Physicists at the University of Basel have now shown for the first time the combination with a third layer can result in new material properties also in a three-layer sandwich of carbon and boron nitride. This significantly increases the number of potential synthetic materials, report the researchers in the scientific journal Nano Letters.

Last year, researchers in the US caused a big stir when they showed that rotating two stacked graphene layers by a “magical” angle of 1.1 degrees turns...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Researchers measure near-perfect performance in low-cost semiconductors

18.03.2019 | Power and Electrical Engineering

Nanocrystal 'factory' could revolutionize quantum dot manufacturing

18.03.2019 | Materials Sciences

Long-distance quantum information exchange -- success at the nanoscale

18.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>