26 Aug

A Tribute to Prof. Mojmír Petráň - Inventor of the Spinning Disk Confocal Microscope

Professor Mojmír Petráň, inventor of the Confocal Spinning Disk Microscope, died at the age of 99 years on 13th August 2022.

A child of the 1920s, Mojmír Petráň fought for freedom, with the Czech Resistance against Nazis and in the Prague Uprising of 1945. Following World War II, he studied medicine at the Charles University in Prague, then specialized in electrophysiology in the 1950s at the Czechoslovak Academy of Sciences. He gained his doctorate in Medical Physics in 1960 and from 1960-71 he was Head of the Institute of Biophysics at the Charles University, Faculty of Medicine, in Pilsen.

The tandem scanning spinning disk confocal microscope (TSCM) was conceived by Petráň while on sabbatical at Yale University. Together with his colleague Milan Hadravský, he constructed the first prototype in 1965 in Pilsen. The U.S. patent for their invention was granted in 1967 and the pair went on to manufacture a significant number of these devices which were exported to the USA, UK and Korea.

After the Soviet invasion in 1968, Petráň and Hadravský were banned from travel abroad and publishing in Western journals. Petráň lost his Chair position at the Institute of Biophysics. It was not until the late '80s, when Professor Alan Boyde brought their invention back to the West that it became more widely recognized.

A collaboration with Boyde at University College London, introduced the author to TSCM and Petráň in 1988. The resulting collaboration explored chromatism and chromatic aberrations in confocal microscopes.

Meanwhile, the potential for spinning disk confocal was recognized by others and a particularly good solution, exploiting microlens arrays, was patented by Favro et al. in 1991. The patent was licensed to Yokogawa Corporation and the CSU series was commercialized around 1996.

In the following decade, solid state lasers became available and Andor led the way with EMCCD technology and iXon cameras, which proved to be a great match for CSU. Andor distributed Yokogawa CSU scanners from 2005 to 2015, integrating them into its Revolution microscopy systems.

In 2016, Andor launched Dragonfly, a new spinning disk platform, building on the experiences of the previous decades. Then, in 2021, Andor's BC43 was introduced the first truly benchtop spinning disk confocal with integrated microscope, laser engine and scientific CMOS detector.

While the details have changed, the desire to visualize biology in all its multi-dimensional living glory is what drives us today, inspired by Mojmír Petráň, his colleagues and a shared vision.

On the shoulders of giants we stand…

Words by Dr. Mark Browne, Andor Technology and Dr. Jan Peychl, MPI-CBG, Dresden.