Australian among 2025 Nobel Prize winners

The first of the 2025 Nobel Prizes have been announced — and this year’s awards recognise an Australian scientist for a discovery he made over 35 years ago.

Physiology or Medicine

The Nobel Assembly at Karolinska Institutet has decided to award the 2025 Nobel Prize in Physiology or Medicine to Mary E Brunkow, Fred Ramsdell and Shimon Sakaguchi, for their fundamental discoveries concerning peripheral immune tolerance, which prevents the immune system from harming the body.

Back in 1995, when many researchers were convinced that immune tolerance only developed due to potentially harmful immune cells being eliminated in the thymus, Sakaguchi showed that the immune system is more complex and discovered a previously unknown class of immune cells, which protect the body from autoimmune diseases. Then in 2001, Brunkow and Ramsdell realised that a mouse strain that was particularly vulnerable to autoimmune diseases had a mutation in a gene they named FOXP3 — and showed that mutations in the human equivalent of this gene cause a serious autoimmune disease, IPEX.

Two years after this, Sakaguchi was able to prove that the FOXP3 gene governs the development of the cells he identified in 1995. These cells, now known as regulatory T cells, monitor other immune cells and ensure that our immune system tolerates our own tissues. The laureates’ discoveries have since spurred the development of medical treatments for cancer and autoimmune diseases as well as more successful transplantations.

Physics

The Royal Swedish Academy of Sciences has decided to award the 2025 Nobel Prize in Physics to John Clarke, Michel H Devoret and John M Martinis, for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit.

In 1984 and 1985, the researchers conducted a series of experiments with an electronic circuit built of superconductors, components that can conduct a current with no electrical resistance. In the circuit, the superconducting components were separated by a thin layer of non-conductive material — a set-up known as a Josephson junction. By refining and measuring all the various properties of their circuit, they were able to control and explore the phenomena that arose when they passed a current through it. Together, the charged particles moving through the superconductor comprised a system that behaved as if they were a single particle that filled the entire circuit.

This macroscopic particle-like system is initially in a state in which current flows without any voltage. The system is trapped in this state, as if behind a barrier that it cannot cross. In the experiment the system shows its quantum character by managing to escape the zero-voltage state through tunnelling. The system’s changed state is detected through the appearance of a voltage.

The laureates could also demonstrate that the system behaves in the manner predicted by quantum mechanics — it is quantised, meaning that it only absorbs or emits specific amounts of energy. Their discovery has provided opportunities for developing the next generation of quantum technology, including quantum cryptography, quantum computers and quantum sensors.

Chemistry

The Royal Swedish Academy of Sciences has decided to award the 2025 Nobel Prize in Chemistry to Susumu Kitagawa, The University of Melbourne’s Richard Robson and Omar M Yaghi, for the development of metal–organic frameworks (MOFs) — molecular constructions with large spaces through which gases and other chemicals can flow. By varying the building blocks used in the MOFs, chemists can design them to capture and store specific substances; MOFs can also drive chemical reactions or conduct electricity.

It all started in 1989, when Robson tested utilising the inherent properties of atoms in a new way. He combined positively charged copper ions with a four-armed molecule; this had a chemical group that was attracted to copper ions at the end of each arm. When they were combined, they bonded to form a well-ordered, spacious crystal, like a diamond filled with innumerable cavities.

Kitagawa and Yaghi later provided this building method with a firm foundation, through a series of discoveries made between 1992 and 2003. Kitagawa showed that gases can flow in and out of the constructions and predicted that MOFs could be made flexible, while Yaghi created a very stable MOF and showed that it can be modified using rational design, giving it new and desirable properties. In the years since, chemists have built tens of thousands of different MOFs, with applications that include separating PFAS from water, breaking down traces of pharmaceuticals in the environment, capturing carbon dioxide and harvesting water from desert air.

The Nobel Prizes in Literature, Peace and Economic Sciences will be announced in the coming days. As per tradition, the main Nobel Prize award ceremony will take place in Stockholm on 10 December — the anniversary of Alfred Nobel’s death.

Image caption: Nobel Prize in Chemistry winner Professor Richard Robson. Image credit: Paul Burston/University of Melbourne.