The institute
FEMTO's news

You are here

Understanding energy transfers during photosynthesis

Using three pigments manipulated by scanning tunneling microscopy, researchers from IPCMS and FEMTO-ST are studying energy transfers between molecules to gain a finer understanding of the photosynthesis mechanism in plants. This work is published in Nature Chemistry.

Photosynthesis allows plants to transform solar energy into chemical energy necessary for their growth. This mechanism is carried out by a complex assembly of organic molecules, the pigments, whose purpose is to collect, transport and transform solar energy. The successive energy transfers are made by jumps between neighboring molecules, but also via collective phenomena, potentially coherent, involving simultaneously a larger number of pigments. To better understand these effects, it is necessary to unravel these pigment assemblies in order to study separately the role of each active unit in photosynthesis. In this study, using a "bottom-up" approach, the researchers use model pigments isolated from each other, which they then reassemble to form the first functional bases capable of reproducing the energy transfer mechanisms involved in photosynthesis.

Three different pigments are thus deposited by evaporation on a surface in very small quantities, in order to have molecules that are far from each other. A scanning tunneling microscope is used to visualize each of the pigments, and then to manipulate them one by one, in order to form structures close to the elementary bricks observed in natural photosynthetic systems. A first pigment, called donor, absorbs an excitation. A second pigment acts as an intermediary which, depending on its nature, increases or reduces the efficiency of the energy transfer. A third pigment, acceptor, transforms this energy into photon. In the experiment, the scanning tunneling microscope is used to emit an electron to generate a local excitation of one of the pigments, which allows to reproduce the mechanism of absorption of a photon by a pigment of the plant. The energy received by the acceptor is converted into photons rather than chemical energy. The reaction is thus a reverse photosynthesis, with the capture of an electron leading to the release of a photon, but the energy transfers take place in the same way.

This approach allows to control the distance and orientation between the pigments with a precision close to the distance between two atoms and the researchers were able to highlight the role played by interactions in the energy transfer mechanism. These interactions are either long range, such as dipole-dipole, or short range, the latter depending on a mechanism, called exchange, specific to quantum physics. This study also shows that, depending on its chemical nature, the intermediate pigment can play a role of active relay of the excitation, amplify the energy transfer between two molecules without directly intervening in the process, or partially block it.

Thus, by using elementary bricks similar to those used by the plant to transport and convert solar energy, the researchers have developed a platform to reproduce the fine mechanisms of photosynthesis and, in the near future, elucidate them.

Schematic of the experiment where the tip of a scanning tunneling microscope (in gray) is used to excite an assembly of three pigments close to those involved in plant photosynthesis. The excitation generated in the blue pigment is transferred, sequentially, to the red pigment where the energy is transformed into photon (top). Hyper-resolved fluorescence image of the three pigments (bottom).    (Credit: Guillaume Schull, IPCMS)

 

DOI : 10.1038/s41557-021-00697-z.

Contact at FEMTO-ST : Frédéric Cherioux, CNRS Senior researcher

See the article published on the INP CNRS website

  • Entrepreneurs-PhD Award in Bourgogne-Franche-Comté: 3 laureates from FEMTO-ST institute

    Vladimir Gauthier (CellSelect project), Aliyasin El Ayouch (Metabsorber project), Romain Viala (MICAD project),   were rewarded during the regional final which took place on October 16 in Dijon

    Read more
  • « Micron d’or » Award at the international microtechnology trade fair

    For one of the most dexterous miniature robots with 7 degrees of freedom, allowing micromanipulation and microassembly in extremely confined spaces

    Read more
  • nanofis de polymères

    Polymer-based nanowires

    Molecules, salt and light :  an easy recipe to provide giant nanowires !

    Read more
  • Discussions about good practices around smart specialization

    In the frame of the 2014-2020 programming of the European Regional Development Funds (ERDF), the European Union has asked all the regions of Europe to draw up a "Smart Specialization Strategy" for research and innovation on their own territory: this is the S3.

    Read more
  • Optical Neural Networks start to learn...

    Work is actively in progress at FEMTO-ST in order to design the photonic architectures dedicated to our future processors that will be computing through artificial intelligence concepts.

    Read more
  • When the light is directed by its magnetic field

    FEMTO-ST researchers have discovered a new optical magnetic interaction to direct light fluxes. These works are published in the journal Light: Science and Applications
    Read more
  • Amar Nath Ghosh awarded at OSA Advanced Photonics Congress

    Amar Nath Ghosh won the Best student paper award of the OSA Advanced Photonics Congress , Zurich.

    Read more
  • Focus on the innovations of the "hydrogen-energy systems" sector

    A few days after the announcement by the government of the launch of a major national hydrogen plan, the Femto-ST institute is organizing on 20 June 2018 at the FCLAB in Belfort, a focus on innovations in the "hydrogen energy systems" sector.

    Read more
  • Robotic assembly of the smallest house in the world

    the handling and assembly capabilities of nanocomponents of the "μRobotex" platform make the buzz on the net and in the international press through the origami manufacturing of a micro-house at the end of an optical fiber whose dimensions are less than the diameter of a hair.

    Read more
  • Nicolas Andreff, receives the scientific award "Charles Defforey" from -Institut de France Foundation

    Awarded May 30 under the Dome of the “ (Institut de France) " by Jean-Paul Laumond, a member of the Academy of Sciences, this Grand Prize crowns the work & skills of Nic

    Read more

Pages