High-resolution AFM in liquid: what about the tip?

Atomic Force Microscopy relies on a nanoscale tip to image and probe samples, often down to the sub-nanometre level. The measurement process depends on the precise geometry and chemical nature of the tip apex, and is therefore difficult to control. In the current issue of Nanotechnology, Akrami and co-workers show that, for measurements in aqueous solutions and on flat samples, the presence of stable hydration sites at the tip apex is key to achieving high-resolution images. These sites can be created on commercial tips using a simple preparation strategy that prevents build-up of interfering contaminants. The findings by Akrami et al also suggest a possible way forward to control the influence of the tip on high-resolution measurements.