Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Towards a light driven molecular assembler


A team of chemists at Kiel University built the first artificial assembler, which uses light as the energy source. These molecular machines are performing synthesis in a similar way as biological nanomachines. Advantages are fewer side products, enantioselectivity, and shorter synthetic pathways since the mechanosynthesis forces the molecules into a predefined reaction channel.

Chemists usually synthesize molecules using stochastic bond-forming collisions of the reactant molecules in solution. Nature follows a different strategy in biochemical synthesis. The majority of biochemical reactions are driven by machine-type protein complexes that bind and position the reactive molecules for selective transformations.

Prof. Dr. Rainer Herges, Sprecher des SFB 677 "Funktion durch Schalten"

Copyright: Herges

Artificial “molecular assemblers” performing “mechanosynthesis” have been proposed as a new paradigm in chemistry and nanofabrication. A team of chemists at Kiel University (Germany) built the first artificial assembler, that performs synthesis and uses light as the energy source.

The system combines selective binding of the reactants, accurate positioning, and active release of the product. The scientists published their findings in the journal Communications Chemistry.

The idea of molecular assemblers, that are able to build molecules, has already been proposed in 1986 by K. Eric Drexler, based on ideas of Richard Feynman, Nobel Laureate in Physics. In his book “Engines of Creation: The Coming Era of Nanotechnology” and follow-up publications Drexler proposes molecular machines capable of positioning reactive molecules with atomic precision and to build larger, more sophisticated structures via mechanosynthesis.

If such a molecular nanobot could build any molecule, it could certainly build another copy of itself, i.e. it could self-replicate. These imaginative visions inspired a number of science fiction authors, but also started an intensive scientific controversy.

The problem of “sticky fingers”

The debate culminated in a cover story of Chemical & Engineering News in 2003 with the key question: “Are molecular assemblers – devices capable of positioning atoms and molecules for precisely defined reactions – possible?” Here Nobel Prize Winner Richard E. Smalley raised two major objections: the “fat fingers” and the “sticky fingers” problem: To grab and guide each individual atom the assembler must have many nano-fingers.

Smalley argued that there is just not enough room in the nanometer-size reaction region to accommodate all the fingers of all the manipulators necessary to have complete control of the chemistry. The “sticky finger” issue arises from the problem that the atoms of the manipulator’s hands will adhere to the atom that is being moved. So it will often be impossible to release the building block in precisely the right spot. Smalley concludes that the fat and the sticky fingers problems are fundamental and cannot be avoided.

Looking at nature’s molecular assemblers

However, in nature numerous examples of molecular assemblers exist, such as the ribosome, nonribosomal peptide synthetases, polyketide synthases and ATP-synthase. “In terms of molecular assemblers we can state, if nature is using molecular assemblers for synthesis, chemists should - at least in principle - be able to build and operate artificial assemblers in the laboratory”, says Rainer Herges, professor for Organic Chemistry and spokesperson of the Collaborative Research Centre 677 “Function by Switching” at Kiel University.

Herges and his team now have built the first artificial assembler, which uses light as the energy source. Looking at molecular assemblers in nature they tried to systematically reduce their sophistication and complexity to a level, achievable with synthetic chemistry. The synthesis of ATP from ADP and phosphate and the non-ribosomal peptide synthetases served as paragons.

Photoswitchable ligand guides through a reaction

They grab the reactants, four vanadate ions, bring them in close proximity and concatenate them into rings. By positioning the reactants, a photoswitchable ligand guides the reactants through a specific reaction channel, and a molecule is formed that is not present in the starting solution.

The photochemical switching of the ligand to a non-binding state also triggers the release of the product – and solves the “sticky finger” problem. The research team chose UV-light as the external energy source because it is convenient to apply and no interfering byproducts are formed in contrast to chemical energy sources.

Paradigm shift in chemical synthesis

Similar molecular machines, such as assemblers that condensate amino acids to proteins would trigger a paradigm shift in chemical synthesis. Obvious advantages are fewer side products, enantioselectivity, and shorter synthetic pathways since the mechanosynthesis forces the molecules into a predefined reaction channel. “Moreover, the ring product is higher in energy as the starting material. In other words, light energy is converted to chemical energy”, emphasizes Herges.

“Although Mechanosynthesis with artificial molecular assemblers is extremely challenging, it is worthwhile investigating and could provide a new way for light energy conversion.”

The work was supported by the German Research Foundation (DFG) via the Collaborative Research Center 677 "Function by Switching"

A Photo is available to download:
Caption: Professor Rainer Herges, Spokesperson of the Collaborative Reserch Center 677 „Function by Switching“
Copyright: Herges

Wissenschaftliche Ansprechpartner:

Prof. Dr Rainer Herges
Institute of Organic Chemistry
Spokesperson Collaborative Research Center 677 “Function by Switching”
Kiel University
Tel.: +49 (0)431 880 2440


Hanno Sell, Anika Gehl, Daniel Plaul, Frank D. Sönnichsen, Christian Schütt, Felix Köhler, Kim Steinborn & Rainer Herges: Towards a light driven molecular assembler. Communications Chemistry volume 2, Article number: 62 (2019),

Weitere Informationen:

Dr. Boris Pawlowski | Christian-Albrechts-Universität zu Kiel

More articles from Life Sciences:

nachricht Happy hour for time-resolved crystallography
17.09.2019 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Too much of a good thing: overactive immune cells trigger inflammation
16.09.2019 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Happy hour for time-resolved crystallography

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.

The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.

Im Focus: Modular OLED light strips

At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.

Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...

Im Focus: Tomorrow´s coolants of choice

Scientists assess the potential of magnetic-cooling materials

Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....

Im Focus: The working of a molecular string phone

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.

This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.

Im Focus: Milestones on the Way to the Nuclear Clock

Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.

If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

AI for Laser Technology Conference: optimizing the use of lasers with artificial intelligence

29.08.2019 | Event News

Latest News

Novel mechanism of electron scattering in graphene-like 2D materials

17.09.2019 | Materials Sciences

Novel anti-cancer nanomedicine for efficient chemotherapy

17.09.2019 | Health and Medicine

Fungicides as an underestimated hazard for freshwater organisms

17.09.2019 | Ecology, The Environment and Conservation

Science & Research
Overview of more VideoLinks >>>