Critical Assessment of the Evidence for Striped Nanoparticles

Abstract

There is now a significant body of literature which reports 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, in addition to new experimental measurements of a simple control sample comprising entirely unfunctionalised particles, we 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, or by issues with 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 the reported results can alternatively be explained as arising from a combination of instrumental artefacts and inadequate data analysis techniques.

A Thermodynamics Model for the Emergence of a Stripe‐like Binary SAM on a Nanoparticle Surface

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Machine learning at the (sub)atomic scale: next generation scanning probe microscopy

“…Image interpretation, the analysis of spectroscopic data, and the evaluation of probe-induced atomic/molecular manipulation events are also each often fraught with difficulty; the microscopist must continually guard against, and correct for, artefacts due to instrumental effects and/or a non-ideal tip apex [6][7][8][9][10]. Correcting for each of these is, however, often a matter of exploiting the tacit knowledge and expertise of seasoned 'SPM-ers' , with each research group often having its own recipes for scanning, tip preparation/recovery, and atomic manipulation that have been transferred from scientist to scientist over a period of time.…”

TAT and HA2 Facilitate Cellular Uptake of Gold Nanoparticles but Do Not Lead to Cytosolic Localisation

“…These methods have flaws, among which their low throughput, invasiveness and cytotoxicity [ 7 , 11 – 13 ]. Some have been highly disputed [ 14 – 17 ]. Therefore improving the efficiency of delivery of nanomaterials targeted to the cell cytosol by avoiding or disrupting the endosomal entrapment remains a major challenge.…”