Biophysical Society Bulletin | January 2026

In Memoriam

Jochen Guck

On October 3, 2025, Jochen Guck (1973– 2025) passed away after a prolonged illness—unexpectedly and far too early. Jochen was born on January 19, 1973, in Schweinfurt, Germany, and grew up in the small rural town of Bad Königshofen. Already in his youth, he had to cope with a heavy blow of fate when he was confined to a wheelchair after a car accident. Jochen studied physics in Würzburg, Germany, and, through the “Amerika-Pro

blood and other cell samples at previously unattainable speed: real-time deformability cytometry. During 2013–2019 he also served Biophysical Journal as an editorial board member. His extraordinarily broad expertise in medical physics, cell me chanics, and optics ultimately led to his appointment in 2018 as Director at the Max Planck Institute for the Physics of Light and at the newly founded Max-Planck-Zentrum für Physik und Medizin in Erlangen, Germany, with a chair at the Friedrich-Alexander Uni versität Erlangen-Nürnberg, Germany. There, he demonstrated in impressive ways how transformative single-cell mechanical anal ysis can be for biomedical research. Particularly notable are his studies on the mechanical characterization of blood cells directly from patient samples, opening up new diagnostic possibilities for hematological and immunological diseases. Equally impressive were his contributions to the advancement of Brillouin micros copy, a method that enables direct imaging-based measurement of mechanical properties. The enormous scientific impact of his work is also reflected in the Greve Prize awarded to him by the Leopoldina in 2024. Beyond his scientific excellence, Jochen Guck was an extraor dinary mentor. He had a unique ability to share success and to make young colleagues visible. Many of his former group mem bers have gone on to pursue successful scientific careers them selves and now hold professorships or other leadership positions in Germany and abroad. Jochen consistently fostered a lively, inspiring community around him—shaped by his generosity, his ambition, and his remarkable talent for helping people grow through precise and constructive feedback. Few understood as well as he did how to build bridges across disciplinary and institu tional boundaries and to bring together the right people to enable major scientific breakthroughs. He was a connector, a founder of multiple companies, and a reliable supporter of young talent. His passion for science remained unbroken until the end, and it continued to inspire even when his illness had already severely limited him. Those who knew Jochen know that he was marked by extraor dinary clarity, determination, and inner strength—qualities that carried him through many challenges in his life and endowed him with remarkable resilience. Particularly striking was his attitude of never avoiding situations in which his disability posed a challenge. On the contrary: he used such moments to draw attention to the barriers faced by people with disabilities in everyday life, while si multaneously demonstrating that one can operate at the highest levels despite these obstacles. We will deeply miss his brilliant ideas, his dry humor, and his uniquely direct yet deeply empathetic way of engaging in discus sions. With the loss of Jochen Guck, biophysics—and especially the field of cell and tissue mechanics—loses an outstanding scientist, teacher, and unforgettable colleague. — Timo Betz , Kristen Franze , Jona Kayser , Moritz Kreysing , and Franziska Lautenschläger

Jochen Guck

gramm,” went to Austin, Texas for his master’s thesis. This was a formative experience and also where he met his later doctoral advisor, Josef Käs . Käs recognized Jochen’s exceptional poten tial early on and offered him a PhD position in Austin. This very fruitful collaboration led to a remarkable number of important publications that would profoundly shape Jochen’s scientific path. Together, they developed the “optical stretcher,” an advance ment of the now Nobel-Prize–winning optical trap. This system allowed cells to be deformed without mechanical contact—and Jochen was able to show that cancer cells are systematically softer than healthy cells. The two associated papers, published in Biophysical Journal , have been cited more than 3,000 times and have fundamentally influenced cancer research. After completing his PhD in the United States in 2001, Jochen skipped the usual postdoctoral phase and became a junior research group leader at the Institute for Soft Matter Physics in Leipzig. Over the following five years, he built up a powerful research group that further explored the potential of the optical stretcher and developed new techniques for measuring cell me chanics. At the same time, he dedicated himself to other exciting questions in biophysics—particularly in the field of the nervous system. One especially noteworthy contribution was a ground breaking study in which he and his colleagues showed that Müller cells in the retina function as optical waveguides, thus elegantly improving the seemingly “awkward” arrangement of the verte brate retina. In 2007, Jochen accepted a position at the University of Cam bridge as a Lecturer. There, a new Center for Medical Physics was being established, and he played a key role as a founding mem ber. In Cambridge, his scientific focus expanded significantly—still driven by questions of cell mechanics, but increasingly also by optics and the physics of biological tissues. His great potential did not go unnoticed for long: in 2012, he was appointed as an Alexander von Humboldt Professor in Dresden, where he took up a chair in cellular machines. In the following years, he developed a novel, highly efficient method to measure the mechanical properties of cells rapidly and precisely. Inspired by microfluidic concepts of the optical stretcher, he combined hydrodynamic force generation with high-speed cameras and relevant biomedical applications to characterize

January 2026

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