A 900kg stone is a perfect place to rest

 “Life is nothing but an electron looking for a place to rest”. A priori, this is a statement difficult to understand. Don’t worry, after reading this IBEC’s face of the month, you will discover everything about electrons and quantum tunnelling, thanks to Manuel López and his work at the Nanoprobes and nanoswitches group. But first, let’s get to know him a little bit better.

Manuel studied physics at the University of Sevilla and then did a master in biophysics in Paris. The adjective that would describe best Manuel is curious. He loves to ask himself questions and he never stops, he can’t stand still a while, like an electron, he could be everywhere and nowhere at the same time! He also plays the drums and he is also learning to be a clown. But his most important interest and one of his biggest concerns is the future of the planet. We know, quite an impressive mix of interests.

One question is constantly on his mind: how could we get abundant sources of energy that were available to everyone? One day Manuel popped up in Pau’s Gorostiza laboratory. When Pau explained him that in their research team they were working on extracting electrons from the protein that does photosynthesis, Manuel knew that IBEC was his place.

In the Nanoprobes and nanoswitches group they do basic science and seek to understand how proteins exchange electrical charge. In the photosynthesis of algae and bacteria, the photosynthetic complex that they study takes advantage of sunlight to exchanging electrons with partner proteins, accepting them at low energy and donating them at high energy. The Nobel Prize-winning physiologist Albert Szent-Györgyi said “Life is nothing but an electron looking for a place to rest” referring to the biochemical reactions that articulate life. The plant photosystem excites the electrons to the highest energy level in biochemistry and from there, the magic of life happens as electrons look for a place to rest.

But how do they study such small things in the lab? To study the photosystem, they use a tunnelling microscope, a microscopy technique so sensitive that it is capable of solving surfaces as thin as the thickness of an atom.

Concretely, Manuel designs and performs electron exchange experiments with proteins using a tunnelling microscope that allows to visualize and interact with proteins that are 10 times smaller than the wavelength of visible light and therefore cannot be resolved by a conventional optical microscope.

To achieve this atomic resolution, the famous “place to rest”, it is necessary to avoid any kind of vibrations, because they prevent these measurements. Manuel has designed a 900 kg stone and the springs that hold it to the ceiling that absorb seismic vibrations. Thanks to this, they have been able to measure for the first time the electronic exchange between a single photosynthetic complex and it’s protein partner. The current output of a single photosynthetic complex is ridiculously small, however probing photosynthetic complex at this level of detail its essential for the biohybrid photovoltaic scientific community, who are trying to develop protein based solar panels.

 

During the last 4 years that they have been working on this project, Manuel and his colleagues in the team have taken close to 200,000 tunnel current curves. “This has allowed us to reveal some of the details of the charge transfer between these proteins, which are capable of exchanging charge over a long distance, more than 4 nm (in the nanometric world, believe me, this is a long distance) in the aqueous medium in which they are found, which intrigues and amazes us in equal measure” says Manuel.

Now, the lab of Pau Gorostiza has moved to the Cluster II with two brand-new spaces. Before, they were divided between the Helix building and the Bellvitge hospital, billions of nanometres apart. So, if you want to take a break, we are sure that Manuel will be more than pleased to show you around their new spaces while he explains you everything about the nanoworld, electrons, 900kg stones and quantum tunnelling. Don’t be shy and pay them a visit 😉