AMBER scientists develop new technique to image fragile materials

5 March 2021

A team of researchers based at the Advanced Microscopy Laboratory (AML), Trinity College Dublin have developed a new technique that can significantly help scientists to image sensitive samples such as biological or energy materials. The team’s research has garnered significant attention in the world of microscopy, and secured a coveted cover in the Journal of Microscopy and Microanalysis.

The AML houses a key resource for scientists: a range of electron microscopes that are capable of imaging materials to tiny scales, millions of times smaller than a traditional optical microscope. Electron microscopes achieve this by hitting samples with a stream of electrons, a type of subatomic particle, that interact with the material under investigation and then scatter. This scattering effect is then picked up by detectors to form an image. But, unlike what might be expected, using more electrons does not necessarily equate to a better final picture. In certain electron microscopes, and for sensitive samples, a ‘low-dose’ of electrons is preferable to create reliable observation of samples in their true state and to preserve the sample. Unfortunately, although this is preferable, the resulting images suffer from unacceptable artefacts, including signal-streaking and detector-afterglow. It is this specific challenge of low-dose electron microscopy that the team has managed to crack – by improving the detection speed of a particular detector in the electron microscope called the annular dark-field (ADF) detector.

Tiarnan Mullarkey, first author of the paper explains:

“Our improvement to detector technology allows more efficient electron detection, and so less electrons need to be used to image our samples. Therefore the imaging of samples previously too susceptible to damage may be possible, whether biological tissues or novel nanomaterials. One of the most important aspects in the improvement we have made is that this is a retrofittable technology which can extend the lifetime and performance of current detectors for a low cost”.

Prof. Lewys Jones, Principal Investigator at the AML, Trinity College Dublin’s School of Physics, and President of the Microscopy Society of Ireland (MSI), who directed the research with Clive Downing, is looking to the future with this research:

“I’m delighted to have directed this piece of research with Clive Downing and Tiarnan Mullarkey. It is particularly exciting for me to promote Irish research this year while I am President of MSI, which seeks to highlight microscopy across scientists and the public on the island of Ireland. The next research steps are already underway for us.  Tiarnan will test applications for our approach, such as imaging biological materials, and hopes to develop a hardware module that people can plug into existing microscopes so that the technology will assist a wide scientific audience. This can impact cost and is a more environmentally mindful way to grow experimental capabilities and extend instrument lifetimes”.

Commenting on his plans during tenure as President of MSI, Prof. Jones says that he “hopes to grow the society, serving our member’s needs, and representing the microscopy community during these strange times. New online and hybrid conferences and schools outreach will enable us to reach even more people and increase the profile of microscopy in research, industry, and education”.