Response to "critical assessment of the evidence for striped nanoparticles"

Quy Khac Ong, Francesco Stellacci

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Stirling et al., (10.1371/journal.pone.0108482) presented an analysis on some of our publications on the formation of stripe-like domains on mixed-ligand coated gold nanoparticles. The authors shed doubts on some of our results however no valid argument is provided against what we have shown since our first publication: scanning tunneling microscopy (STM) images of striped nanoparticles show stripe-like domains that are independent of imaging parameters and in particular of imaging speed. We have consistently ruled out the presence of artifacts by comparing sets of images acquired at different tip speeds, finding invariance of the stipe-like domains. Stirling and co-workers incorrectly analyzed this key control, using a different microscope and imaging conditions that do not compare to ours. We show here data proving that our approach is rigorous. Furthermore, we never solely relied on image analysis to draw our conclusions; we have always used the chemical nature of the particles to assess the veracity of our images. Stirling et al. do not provide any justification for the spacing of the features that we find on nanoparticles: ∼1 nm for mixed ligand particles and ∼ 0.5 nm for homoligand particles. Hence our two central arguments remain unmodified: independence from imaging parameters and dependence on ligand shell chemical composition. The paper report observations on our STM images; none is a sufficient condition to prove that our images are artifacts. We thoroughly addressed issues related to STM artifacts throughout our microscopy work. Stirling et al. provide guidelines for what they consider good STM images of nanoparticles, such images are indeed present in our literature. They conclude that the evidences we provided to date are insufficient, this is a departure from one of the authors' previous article which concluded that our images were composed of artifacts. Given that four independent laboratories have reproduced our measurements and that no scientifically rigorous argument is presented to invalidate our STM images, and also given that Stirling et al. do not contest the quality of our recent STM images, we re-Affirm that specific binary mixture of ligands spontaneously form features in their ligand shell that we describe as stripe-like domains ∼1 nm in width.

Original languageEnglish
Article numbere0135594
JournalPLoS One
Volume10
Issue number11
DOIs
Publication statusPublished - Nov 10 2015

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scanning tunneling microscopy
Scanning Tunnelling Microscopy
Scanning tunneling microscopy
nanoparticles
Nanoparticles
Artifacts
image analysis
Ligands
Imaging techniques
Binary mixtures
Invariance
Gold
microscopes
Image analysis
Publications
Microscopy
microscopy
Microscopic examination
Microscopes
chemical composition

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Response to "critical assessment of the evidence for striped nanoparticles". / Ong, Quy Khac; Stellacci, Francesco.

In: PLoS One, Vol. 10, No. 11, e0135594, 10.11.2015.

Research output: Contribution to journalArticle

Ong, Quy Khac ; Stellacci, Francesco. / Response to "critical assessment of the evidence for striped nanoparticles". In: PLoS One. 2015 ; Vol. 10, No. 11.
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