Alan Agar Award for Electron Microscopy

Dr Alexandra Pacureanu’s work has impacted on the biomedical research community in profound ways, altering the way we view the possibilities of high resolution imaging of soft biological tissues with synchrotron radiation.

She developed and applied X-ray holographic nano-tomography on the ID16A nano-imaging beamline at the European Synchrotron Radiation Facility (ESRF). The technique is unique in enabling imaging of (relatively) large intact tissue samples (mm scale) with similar contrast and structural resolution to electron microscopy (EM). Samples may be imaged at room or cryo temperatures, and are often stained with heavy metals and embedded in resin using the same methods as used in EM. Indeed, much of Alexandra’s work incorporates X-ray imaging into correlative light and EM workflows. 

During the recent long shutdown phase at ESRF, Alexandra quickly built her standing in the biomedical research community, at some of the most prestigious research institutes in Europe and the US. She focused her biological question on the brain, in the area of Connectomics, where light and electron microscopy struggle to combine the large fields of view required to follow individual neurons with the resolution required to image individual synapses.

Chair of the RMS Electron Microscopy Section Dr Lucy Collinson, and Chair of the X-Ray Focused Interest Group Dr Liz Duke, said: “Alexandra possesses that rare skill of being fully conversant in X-ray synchrotron optics and beamline and experiment design, whilst also contributing fundamental research at an international level in biology and particularly neuroscience. The technique she has pioneered looks set to replace both light and electron microscopy for a swathe of this critical scientific effort. It is a privilege and a delight to announce her as the recipient of this award.”

Wanda Kukulski is one of the rising stars in the field of Biomedical Electron Microscopy and has made significant contributions especially in the field of Correlative Light Electron Microscopy.

Wanda studied Biology at the University of Basel, Switzerland, before undertaking a PhD in biophysics at Basel in the group of Prof. Andreas Engel. The title of her thesis was: “Structure and functions of Aquaporins”. During this time she published a 5Å structure of the plant aquaporin SoPIP2;1. She stayed at Basel, at the M. E. Müller Institute, Biozentrum, for her first postdoctoral position before moving to EMBL Heidelberg in 2008 on an EIPOD position. She joined the groups of John Briggs in the Structural and Computational Biology Unit and Marko Kaksonen from the Cell Biology and Biophysics Unit. This combination turned out to be a very fruitful one.

It is in this period where she did her seminal work in the field of Correlative Light Electron Microscopy developing techniques that have been an example to follow in the field. Through the introduction of fiducial markers she was able to generate a very precise overlay of the LM and EM data, much more precise than was possible to that date. She then used that technology to combine light microscopy with high-resolution electron tomography and decipher the very early steps of clathrin-mediated endocytosis. Her 2 most exciting papers were published in Journal of Cell Biology and Cell.

In 2015 she moved to the MRC Laboratory for Molecular Biology in Cambridge to set up her own group.  

Professor Kirkland is known for being an electron microscopist with an incredibly wide-ranging understanding and knowledge of the field. Some of his most high-profile research has been in exit-wave reconstruction. His arguably most notable work is the development of super-resolved exit-wave reconstruction methods through which, using an aberration-corrected instrument, he demonstrated a remarkable improvement in resolution to 78 picometres at 200 kV, more than 40% better than the axial limit. As published in Science, Professor Kirkland characterised of individual 2 x 2 and 3 x 3 atom nanocrystals encapsulated in a single walled carbon nanotube solved using exit-wave reconstruction to locate single I and K atoms.

Professor Kirkland was the first to clearly develop a comprehensive understanding of signal and noise transfer and the effects of this on the performance of electron image detectors. His innovative work on detector characterisation showed that the power spectrum of an evenly illuminated white-noise image is in general not equal to the modulation transfer function (MTF) and that the conventional techniques to measure the MTF give over-optimistic estimations of the MTF.

Professor Kirkland has shown that he is able to fully appreciate, identify, contribute and disseminate entirely new developments across the broad field of electron microscopy to both the European and international community.

Dr Kociak has developed a new variety of Electron Microscopy (EM), capable of performing cathodoluminescence (CL) experiments simultaneously with the electron microscopy. This has been dubbed as ‘the beginning of a unification of optical and electron microscopy.’

Dr Kociak and the team he has built over the past 10 years has played a leading role in the emergence of electrons in a STEM technique for nanooptics. This has involved both theoretical and experimental developments, important technical developments designing and producing innovative CL-compatible sample holders and stages. The unification of two core fields of microscopy – optical and electronic – are currently underway, largely driven by the developments pioneered and pursued by Dr Kociak.