Scanning Helium Microscopy: A Novel Surface Visualization Technique Applied to Microbial Biofilms

Microbial biofilms are complex multicellular aggregates that form on virtually any surface across diverse ecosystems, playing critical roles in environmental processes and infectious

diseases. Biofilms can be found in extreme thermal and pressure conditions in polar regions as well as in deep sea volcanos. Traditional imaging techniques, such as optical and electron

microscopy, have provided valuable insights into biofilm architecture but are often limited by their inability to differentiate between surface and subsurface features. This constraint

can be a result of the thin and transparent nature of the biofilm surface, as well as the sample preparation techniques used for imaging that can create structural artefacts due to

losses of biofilm matrix components. The scanning helium microscope (SHeM) is a new technique that offers an alternative modality for surface imaging. It utilizes neutral helium

atoms with extremely low energy (~ 60 meV) and short wavelength (~0.05 nm) to interact solely with the outermost surface layers of a sample with no effective radiative damage.

Here we present the first images of microbial biofilms visualized with the SHeM and will discuss the development of a new chamber to enable collection of data under temperatures

and pressures that mimic extreme environmental conditions.