  There is now a significant body of literature in which it is claimed that
stripes form in the ligand shell of suitably functionalised Au nanoparticles.
This stripe morphology has been proposed to strongly affect the physicochemical
and biochemical properties of the particles. We critique the published evidence
for striped nanoparticles in detail, with a particular focus on the
interpretation of scanning tunnelling microscopy (STM) data (as this is the
only technique which ostensibly provides direct evidence for the presence of
stripes). Through a combination of an exhaustive re-analysis of the original
data with new experimental measurements of a simple control sample comprising
entirely unfunctionalised particles, we conclusively show that all of the STM
evidence for striped nanoparticles published to date can instead be explained
by a combination of well-known instrumental artefacts, strong observer bias,
and/or improper data acquisition/analysis protocols. We also critically
re-examine the evidence for the presence of ligand stripes which has been
claimed to have been found from transmission electron microscopy, nuclear
magnetic resonance spectroscopy, small angle neutron scattering experiments,
and computer simulations. Although these data can indeed be interpreted in
terms of stripe formation, we show that, just as for the STM measurements,
rather more mundane interpretations can account for the reported results.
