Note: mechanically and chemically stable colloidal probes from silica particles for atomic force microscopy

In this note we present a novel approach to prepare colloidal probes for atomic force microscopy by sintering. A central element of this procedure is the introduction of an inorganic "fixation neck" between the cantilever and a micrometer-sized silica particle that is acting as probe. This procedure overcomes previous restrictions for the probe particles, which had to be low melting point materials, such as borosilicate glass or latex particles. The here-presented colloidal probes from silica can withstand large mechanical forces. Additionally, they have high chemical resistivity due to the absence of adhesives and the well-studied surface chemistry of colloidal silica.