Imagine going for an MRI scan of your knee. This scan measures the density of water molecules present in your knee, at a resolution of about one cubic millimeter – which is great for determining whether, for example, a meniscus in the knee is torn. But what if you need to investigate the structural data of a single molecule that’s five cubic nanometers, or about ten trillion times smaller than the best resolution current MRI scanners are capable of producing? That’s the goal for Dr. Amit Finkler of the Weizmann Institute of Science’s Chemical and Biological Physics Department. In a recent study, Finkler, PhD student Dan Yudilevich and their collaborators from the University of Stuttgart, Germany, have managed to take a giant step in that direction, demonstrating a novel method for imaging individual electrons. The method, now in its initial stages, might one day be applicable to imaging various kinds of molecules, which could revolutionize the development of pharmaceuticals and the characterization of quantum materials.

So how can one achieve a more precise MRI equivalent that can work on small samples – right down to the individual molecule? Finkler, Yudilevich and Stuttgart’s Drs. Rainer Stöhr and Andrej Denisenko have developed a method that can pinpoint the precise location of an electron. It is based on a rotating magnetic field that is in the vicinity of a nitrogen-vacancy center – an atom-sized defect in a special synthetic diamond, which is used as a quantum sensor. Because of its atomic size, this sensor is particularly sensitive to nearby changes; because of its quantum nature, it can differentiate whether a single electron is present, or more, making it especially suited to measuring the location of an individual electron with incredible accuracy.

“This new method,” says Finkler, “could be harnessed to provide a complementary point of view to existing methods, in an effort to better understand the holy molecular trinity of structure, function and dynamics.” For Finkler and his peers, this research is a pivotal step on the way to precise nanoimaging, and they envision a future in which we would be able to use this technique to image a diverse class of molecules, that will, hopefully, be ready for their close-up.