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 Contacting the molecular world through graphene nanoribbons
19.02.2018 | Elhuyar Fundazioa

nachricht When Proteins Shake Hands
19.02.2018 | Friedrich-Schiller-Universität Jena

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>