An international team of scientists has managed, for the first time in history, to selectively modify individual molecules, breaking or forming bonds between their atoms at will. The advance will make possible the creation of previously unimaginable molecules, according to the Spanish chemist Diego Pena, one of the leaders of the group. “This technique will revolutionize chemistry,” he says. Your inquiry it’s a magazine cover Sciencereference of the best world science.
A molecule is simply a group of atoms. Water – as indicated by its famous chemical formula, H₂O – has two atoms of hydrogen and one oxygen, connected by so-called covalent bonds, in which the electrons are shared. Today, to modify molecules, scientists use a process similar to putting trillions of LEGO bricks in a washing machine, waiting for them to fit together and form the desired product, according to an illustrative comparison used by the chemist Russian Igor Alabugin and his Chinese colleague Chaowei Hu in the magazine itself Science. Peña’s team, meanwhile, used a state-of-the-art microscope capable of focusing on a single molecule one millionth of a millimeter and changing its bonds using electrical pulses.
“We can assemble atoms in an unimaginable way,” rejoices Peña, from the Singular Center for Research in Biological Chemistry and Molecular Materials (CiQUS), at the University of Santiago de Compostela. The scientist, a man from Santiago about to turn 48, paraphrase a famous phrase from the movie blade runner“I’ve seen molecules you wouldn’t believe”. He and his colleagues created different structures with 18 carbon atoms and eight hydrogen atoms, forming rings and other flourishes, reversibly. “If you asked a chemist if it is possible to synthesize some of these molecules, he would tell you that it is impossible, because they would react with the environment and would last for milliseconds,” says Peña.
The authors used an improved version of the scanning tunneling microscope, whose inventors – the German Gerd Binnig and the Swiss Heinrich Rohrer, from the laboratory of the IBM company in Zurich (Switzerland) – won the Nobel Prize in Physics in 1986. These instruments, which require a temperature of about 270 degrees below zero and ultra-high vacuum conditions to ensure the stability of molecules, are capable of imaging surfaces at the atomic level. Peña’s team has already managed to make the cover of the magazine Science in 2012, after obtaining The first picture of bonds between the atoms of individual molecules.
the german physicist Leo Gross, from IBM, is another of the main authors of the survey. “Selective reactions in a single molecule can enable the creation of new, more complex and versatile artificial molecular machines,” says Gross, who imagines a future in which drug synthesis and delivery are improved. “These molecular machines could perform tasks such as transporting other molecules or nanoparticles, manufacturing and manipulating nanostructures, and facilitating chemical transformations,” adds the physicist. To reach this future, it will first be necessary to master this new technique, which is still “in its infancy”, according to its authors.
Peña, Gross and their colleagues played with this molecule of 18 carbon atoms and eight hydrogen atoms, generating three different results using electrical pulses of a few volts. With the same recipe, C₁₈H₈, three different three-dimensional structures are obtained. Researchers can change these configurations over and over again, hundreds of times, making the system react or not with other molecules. Chemists Igor Alabugin and Chaowei Hu, from Florida State University (USA), compare these modifiable molecules to “a Swiss army knife for chemistry”.
The IBM laboratory in Zurich develops these sophisticated microscopes. Peña’s group, on the other hand, come up with diabolical chemical problems that can be solved with these machines. In recent years, the authors have, for example, devoted themselves to the analysis of the molecules present in meteorites. “With conventional techniques, it takes a few million molecules to be able to detect them. With this new technique, the detection threshold is lowered to very small, single-molecule levels,” Peña applauds.
Chemists from the University of Santiago de Compostela and physicists from IBM have also studied the molecular structure of asphaltenes, solid components of petroleum that block pipes and are known as “refinery cholesterol”. When they form a plug, it is necessary to stop the industrial activity and extract it. “We can analyze the structure of asphaltenes to help develop additives that prevent these molecules from self-assembling and precipitating in pipes,” says Peña. His consortium, in which the University of Regensburg (Germany) also participates, received two years ago nine million euros of the European Research Council.
The chemist Diego Peña was in Madrid on May 7 at the farewell concert of one of his favorite bands, totally sinister. Galician musicians, known for their irreverent lyrics with scientific nods, they sang one of their hymns“What is it to be? What is Gasoline? What is nothing? What is eternity? Are we a soul? Are we important? Peña reflects on this material from which human beings and everything else are made. “It is very important for society to realize the value of basic research: knowledge for knowledge’s sake. I want to control how the atoms fit together. What is it worth? Well, for everything, because everything is made of molecules and atoms,” he argues. Applications, such as future molecules, are unimaginable, but we’ll have to wait to see them anyway, Peña points out: “Obviously we’re not going to cure cancer tomorrow.”