'Nuclear spin microscopy' based on quantum sensors

Researchers at the Technical University of Munich (TUM) say they have invented an entirely new field of microscopy, dubbed nuclear spin microscopy. The team can visualise magnetic signals of nuclear magnetic resonance with a microscope: quantum sensors convert the signals into light, enabling extremely high-resolution optical imaging.

Magnetic resonance imaging (MRI) scanners are known for their ability to look deep into the human body and create images of organs and tissues. The new method, published in the journal Nature Communications, extends this technique to the realm of microscopic detail.

“The quantum sensors used make it possible to convert magnetic resonance signals into optical signals. These signals are captured by a camera and displayed as images,” said Dominik Bucher, Professor for Quantum Sensing at the TUM School of Natural Sciences and researcher at the Cluster of Excellence Munich Center for Quantum Science and Technology (MCQST).

At the heart of the new microscope is a tiny diamond chip. This diamond, specially prepared at the atomic level, serves as a highly sensitive quantum sensor for MRI magnetic fields. When irradiated with laser light, it generates a fluorescent signal containing the MRI signal’s information. This signal is recorded with a high-speed camera and enables imaging with a resolution down to 10 millionths of a metre — so fine that even the structures of individual cells can be made visible in the future.

The potential applications of nuclear spin microscopy are many and varied. In cancer research, individual cells could be examined in detail to gain new insights into tumour growth and spread. In pharmaceutical research, the technology could be used to efficiently test and optimise active ingredients at a molecular level. It also offers excellent potential in materials science, such as analysing the chemical composition of thin-film materials or catalysts.

The team has applied for a patent for its development and is already planning to develop the technology further to make it even faster and more precise. In the long term, it could become a standard tool in medical diagnostics and research.

“The fusion of quantum physics and imaging opens up completely new possibilities for understanding the world at the molecular level,” said first author Karl D Briegel.

Image caption: Karl D Briegel with Professor Dominik Bucher and their new microscope. Image credit: Christoph Hohmann/MCQST.