Bringing fuzzy edges into focus
Like many experimental physicists Florian is a tinkerer. He plays around with new variants of super-resolution optical microscopy. He is fascinated by the notion of one day being able to visualize the biochemical machines that carry out basic cellular processes at the level of single molecules. For the work described in his Master’s thesis he received the CeNS Nano Innovation Award.
He has a Bachelor’s degree in Physics from LMU, did his Master’s thesis in Harvard, and is now engaged on an SFB research project for his PhD, under the supervision of Professor Ralf Jungmann at LMU and the MPI for Biochemistry in Garching. But it’s now eight in the morning, and what Florian needs most is a cup of coffee. After all he was up until three, working on a new research paper. This will be the eighth journal article in his publication list, and the first as lead author – and he’s still in the first year of his PhD. That makes him sound like a high-flier, but Florian (31), who comes from Kaufering, only began his university studies after completing an apprenticeship as an electrician. “I could have gone on to become an electrical engineer. But I wanted to study physics, as the natural sciences were always my primary interest,” he says. It was undoubtedly the right decision. He was soon engrossed in experimental physics, and in Professor Jungmann – who was then a postdoc – he found an inspiring mentor. “The facilities and opportunities for DNA-based nanotechnological research in Munich are ideal, because several groups are working on diverse aspects of the field. And we all meet regularly to discuss and exchange ideas,” he explains. The idea for his Master’s project was conceived in the Emmy Noether Research Group led by Jungmann in LMU’s Faculty of Physics.
Super-resolution microscopy for ‘crystal-crisp’ images
Tell us about the idea, Florian – what are you actually doing? “I tend to duck this question, because the idea is not that easy to explain,” he says. But then he begins anyway – in the 19th century, with Ernst Abbe, the German physicist who calculated from first principles the maximal resolution attainable with a light microscope of the sort used in his day. The limit was not surpassed for over a century. But the so-called diffraction barrier was eventually breached, and the limit was extended into the nanometer region. The physicists in Jungmann’s group are now working on further refinements of optical microscopy and developing light microscopes with entirely new capabilities. In his Master’s thesis at Harvard University, Florian was able to enhance the DNA-based super-resolution method DNA-PAINT by combining it with the use of a confocal spinning-disk microscope. Super-resolution techniques can visualize single molecules labelled with fluorescent tags, but it is difficult to image the cell as a whole. By implementing the DNA-PAINT method on a spinning-disk microscope, it was possible – even without custom-designed hardware – to image whole cells with approximately 20-fold higher resolution than with conventional light microscopes. His PhD thesis also deals with another innovative method for improving light microscopy. “This one is a bit more complicated,” he remarks, before setting out for the lab to do what he likes best – design and perform experiments.