Georg Nagel, the biophysicist who thinks his Nobel came one patient too early

Georg Nagel

Born	August 24, 1953 Weingarten
Occupation	Botanist
Awards	The Brain Prize · Karl Heinz Beckurts Award · Louis-Jeantet Prize for Medicine

When the call from Stockholm reached Georg Nagel, he was sitting on a terrace in the hills between Naples and Rome, olive trees below him and a lemon tree at his elbow. He did not believe it. Some friends made a point of watching the Nobel announcements every autumn, and he always told them to keep cool. As far as he knew, one patient had benefited from optogenetics, the technique his experiments made possible. Malaria drugs and cancer immunotherapy had helped multitudes. A light switch for brain cells, he thought, was still too young for a prize in medicine.

The Nobel Assembly disagreed. Nagel, a biophysicist at the University of Würzburg, shares the Nobel Prize in Physiology or Medicine with Peter Hegemann and Karl Deisseroth for discoveries concerning light-gated ion channels and optogenetics. His share of the story is the proof. Hegemann had long argued that one protein in the eyespot of the green alga Chlamydomonas both caught light and opened a pore for charged particles, a claim many colleagues doubted. Nagel, at the Max Planck Institute of Biophysics in Frankfurt, put the candidate genes into frog eggs and measured what happened when the light came on. At first it was hard going. Then, as he tells it, a batch of wrongly prepared solutions with a low pH produced a clear signal, and he could work out what he was seeing. It was a fitting accident: the first of the two proteins turned out to be a channel for protons.

The persistence had older roots. Nagel was born on 24 August 1953 in Weingarten, in Upper Swabia, the eldest of five children, and from the age of five he was seriously ill. While his siblings went skiing in nearby Austria, he built a steam engine and radios from the science kits his parents gave him each Christmas, and spent many summer holidays undergoing operations at the university hospital in Würzburg, the city where he would later teach for two decades. He studied biology and biophysics at the University of Konstanz, where Ernst Bamberg, his first biophysics lecturer, became his mentor, and where, as a student, he helped found a café. After his diploma he taught at a private secondary school in Switzerland. Another operation in Würzburg finally stopped the inflammation in his bones; he took up hang gliding and kept teaching until Bamberg invited him to Frankfurt. He went, and completed his doctorate at Goethe University in 1988 with research carried out at the Max Planck Institute.

Five postdoctoral years in the United States followed, at Yale and at Rockefeller University. In New York he met Anna Maria Musti, a molecular biologist from Naples who was a visiting professor at Columbia; she helped him widen his biophysical approach to science. They married in Denmark in 1996 and have a daughter. Back in Frankfurt as a research group leader at the Max Planck Institute, Nagel and Bamberg showed in 1995 that bacteriorhodopsin, a light-driven pump from a microbe, worked when expressed in frog eggs, making animal cells sensitive to light. The frog egg became the test bench for everything that followed.

In 2002, Nagel, Hegemann, Bamberg and colleagues described channelrhodopsin-1 in the journal Science as a light-gated proton channel; Musti is among the co-authors. In 2003, in the Proceedings of the National Academy of Sciences, Nagel’s team showed that channelrhodopsin-2 opened directly to light and let positive ions through, and that it worked in human kidney cells, which depolarized under blue light. Deisseroth wrote to Nagel asking for the gene, and his group at Stanford used it in 2005 to make cultured neurons fire on command, in a paper on which Nagel and Bamberg were co-authors. The same year, working with Alexander Gottschalk, Nagel published one of the first uses of channelrhodopsin to control behaviour in an intact animal, the roundworm Caenorhabditis elegans, using a mutant he had engineered to strengthen the current.

In 2004 he moved to Würzburg as professor of molecular plant physiology at the Julius von Sachs Institute, an unexpected base from which to spend two decades widening a neuroscience tool. With Shiqiang Gao, his group built light-controlled enzymes for the signalling molecules cAMP and cGMP, among them CyclOp, described in 2015. He also turned the method back toward plants, which need light to live and lack the retinal that rhodopsins require. A study in Nature Plants in 2021, with Nagel as senior author, used a light-gated channel taken from an alga to control the growth of tobacco plants. In 2019 he moved to the Institute of Physiology, and from 2021 he continued there as a senior professor.

The prize also draws a line through a crowded room. Nobel rules allow three laureates at most, and the list leaves out Bamberg, Nagel’s mentor, later a director of the Frankfurt institute and a co-author of the channelrhodopsin papers, as well as Edward Boyden, first author of the 2005 neuron paper, and Gero Miesenböck, who had made neurons respond to light earlier with a different system. All six shared the Brain Prize in 2013. Nagel is frank about where the risk lay. Deisseroth has written in review articles that putting channelrhodopsin into neurons was a very risky project; Nagel, in his first interview after the announcement, said he was a little surprised by that, since the protein expressed so well in kidney cells. In the same breath he called Deisseroth’s work in spreading and explaining the tool absolutely important. The medical claim needs the same care. The best-documented human case is a man blinded by retinitis pigmentosa who regained limited sight after gene therapy with an algal channelrhodopsin, reported in 2021; trials continue, and optogenetics is still above all a research method.

Stockholm came at the end of a long run of prizes: the Wiley and Karl Heinz Beckurts prizes in 2010, both with Hegemann and Bamberg, the Louis-Jeantet Prize for Medicine in 2013, the Rumford Prize in 2019 and the Shaw Prize in Life Science and Medicine in 2020, shared with Hegemann and Miesenböck. His formal retirement came at the end of June 2026; he and Musti spend the cold months near Naples, ten degrees warmer than Würzburg on average, he says, and free of fog. His name was still on new papers, including a 2025 study using a calcium-conducting channelrhodopsin in blood platelets. The announcement on 5 October 2026 made him the University of Würzburg’s fifteenth Nobel laureate.

He will receive his medal in Stockholm on 10 December. The protein he first coaxed into a frog egg now opens on cue in laboratories around the world. Whether it reaches a second patient, and a third, is the question he thought the prize should have waited for.

Tags: Nobel Prize, Georg Nagel, Karl Deisseroth, optogenetics, Peter Hegemann, channelrhodopsin, biophysicists