Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Big Tussle Over Tiny Particles

In peer-reviewed papers and on blogs, researchers argue over the existence of striped coatings on nanoparticles

by Lauren K. Wolf
May 26, 2014 | APPEARED IN VOLUME 92, ISSUE 21

Credit: Nature Materials
Stellacci says he imagines the stripes on his nanoparticles to look like the version Glotzer simulated (left) rather than the idealized cartoon he published in 2004 (right).

As truth seekers, scientists often challenge one another’s work and debate over the details. At the first-ever international scientific conference, for instance, leading chemists argued vociferously over how to define a molecule’s formula. A lot of very smart people at the meeting, held in Germany in 1860, insisted that water was OH, while others fought for H2O.

That squabble might seem tame compared with a dispute that’s been raging in the nanoscience community during the past decade. Francesco Stellacci, a professor at the Swiss Federal Institute of Technology (ETH) Lausanne, says his group created gold nanoparticles coated in somewhat orderly striped domains of two different types of molecules. Because of their unique rippled topology, Stellacci claims, these particles enter cells in a way that might be useful for drug delivery and they trap toxic ions, such as methylmercury, showing promise as environmental sensors.

Stellacci’s critics—principally Raphaël Lévy of the University of Liverpool and Philip Moriarty of the University of Nottingham, both in England—say Stellacci’s data don’t prove the existence of stripes and are inconsistent and riddled with errors.

Unlike the scientific debate over a molecule’s formula, today’s differences of opinion don’t typically get hammered out at conferences. They instead get aired in papers and correspondences published in peer-reviewed journals. And increasingly, they’re being carried out on blogs and online commentary sites such as PubPeer, forums that some scientists say can be unfair.

The striped nanoparticle feud, in particular, has reached a fever pitch because of the online buzz it has generated. Lévy and Moriarty write regular posts on Lévy’s blog (, hashing out in gory detail the various aspects of the controversy. Stellacci, who refuses to engage in these discussions, says he feels as though his critics have gone beyond friendly scientific debate and are trying to discredit him.

Lévy began blogging about the disagreement in 2012, after it took three years to get a correspondence that his group wrote, “Stripy Nanoparticles Revisited,” published in the journal Small (DOI: 10.1002/smll.201001465). In it, he questions Stellacci’s original report on striped nanoparticles: a 2004 scanning tunneling microscopy (STM) paper published in Nature Materials while Stellacci was at Massachusetts Institute of Technology (DOI: 10.1038/nmat1116).

During those three years—a long period by peer review standards—the paper was seen by seven referees, and Stellacci was given time to write a full response, which included new data (Small 2012, DOI: 10.1002/smll.201202322).

Credit: Julian Stirling & Ioannis Lekkas
Lévy and Moriarty used an ultrahigh vacuum, low-temperature (77 K) scanning tunneling microscope to image uncoated silver nanoparticles and illustrate how increasing gain (left to right) generates rippled features.

“To Small’s credit, they didn’t have to consider the paper,” Lévy says. He originally sent it to Nature Materials because, as home to the original report, it seemed like the logical place to air concerns,but it was rejected. The glacial publication process and the fact that Small had a difficult time finding referees willing to evaluate the controversial topic pushed Lévy over the edge. “That’s the point at which I started blogging,” he says. “It’s important that we have more channels, more critical evaluations of research.”

The 2004 Nature Materials report mainly used STM images as evidence for stripes. Stellacci’s team coated gold nanoparticles with a mixture of short (mercaptopropionic acid) and long (octanethiol) molecules and then imaged the particles sitting on a flat surface. They saw ripples on the particles’ surfaces that they interpreted as 9- to 10-Å-wide, striped domains of each compound.

Stellacci says he didn’t dream up the idea of different molecules separating into cliques when sticking to an interface. “The community has long known that mixed molecules form patches, or islands, on flat surfaces,” he says.

The ETH Lausanne scientist was interested in whether a binary mixture of thiols would arrange themselves on curved surfaces—nanoparticles—in a similar fashion. Seeing stripes rather than islands, though, was a surprise.

When Lévy looked at the 2004 paper, he was surprised too. But it was because he thought the ripples that appeared in the STM images were artifacts caused by improper use of the microscope.

In STM, a sharp tip is scanned across a surface while a set voltage difference is maintained in between. A user doesn’t want the tip to contact the surface but to glide over it, tracing its features. One parameter a researcher sets to maintain a fixed distance between tip and surface is the gain. If the gain is set too low, the tip may not correct its position fast enough when approaching a bump on a surface and crash. If the gain is set too high, the tip corrects so rapidly that it bounces up and down on the surface in an erratic fashion.

Lévy thought the latter was what he was seeing in Stellacci’s images and made that argument, among others, in his 2012 Small correspondence.

In his response, published simultaneously, Stellacci fired back that he and his group had confirmed the stripes over and over again in peer-reviewed papers after 2004 and that Lévy was ignoring those data. “Science is a process, and it would be fair to assume that later papers offer a better understanding of a system,” Stellacci and coworkers wrote.

Credit: Nature Materials
Critics suggest that the ripples in this STM image, from Stellacci’s 2004 Nature Materials paper, are an artifact.
Credit: Nature Materials
Critics suggest that the ripples in this STM image, from Stellacci’s 2004 Nature Materials paper, are an artifact.

One of the “later” papers to which Stellacci frequently refers was published in collaboration with Sharon C. Glotzer, a chemical engineer at the University of Michigan, Ann Arbor. Glotzer’s group ran computer simulations of two types of molecules on a nanoparticle’s surface and observed that under certain conditions—when the molecules had a particular length or bulkiness relative to one another—they arranged into stripelike domains (Phys. Rev. Lett. 2007, DOI: 10.1103/physrevlett.99.226106).

According to Glotzer, the molecules separate into stripes because of entropy. Longer or bulkier ligands have more room to wiggle their tails at the edges of domains than in the middle of them, she says. Stripes form because they have more edges.

And having now run many simulations that find stripes under conditions similar to those in Stellacci’s experiments, Glotzer says, “from an Occam’s razor point of view, it would be very surprising to me if the stripes weren’t there.”

Nottingham’s Moriarty, a scanning-probe microscopy expert, is careful to say that simulations carried out by Glotzer and others are high quality. But he suggests that a lot of assumptions get made in running them, so they might not reflect reality. Moriarty is also careful to say that stripes may very well exist; he just doesn’t think Stellacci’s evidence—principally, the microscopy data—is convincing.

Moriarty began writing guest posts on Lévy’s blog after the Small papers appeared online in 2012. He, too, was dismayed by the hard time Lévy had getting his criticism into a journal. Publishing in a journal, Moriarty contends, “should be the start of the debate, not the end of it.”

Once involved, the Nottingham microscopist e-mailed Stellacci to ask for the raw data from his 2012 response paper. Stellacci’s group sent over the requested images right away.

Credit: ACS Nano
In this STM image from Stellacci’s 2013 ACS Nano paper, he and his collaborators use dots to mark the tails of molecules coating a gold nanoparticle. The arrows indicate where they think stripes connect the dots.
Credit: ACS Nano
In this STM image from Stellacci’s 2013 ACS Nano paper, he and his collaborators use dots to mark the tails of molecules coating a gold nanoparticle. The arrows indicate where they think stripes connect the dots.

When Moriarty took a look at the data, though, he noticed something he says is a no-no in the world of STM. Typically, an STM user will scan a large area—say 100 by 100 nm—on a surface, he explains. When that user sees a feature of interest, such as a nanoparticle, the researcher will zoom in on it and take a new scan over a smaller area—maybe 10 by 10 nm—to get a better view with higher resolution.

Rather than taking the smaller area scan, Stellacci and his team had been zooming in on the large-area scans with a software program that interpolated between data points and filled in pixels.

Stellacci acknowledged to C&EN that he plotted the data incorrectly. “I wasn’t aware that the software of the microscope was adding points.” But he claims this was only for figures in papers and that the original scans, which have been recently reanalyzed, still show ripples separated by 9 or 10 Å on his particles.

He points to a new set of papers in which stripes on his particles were once again identified, this time by microscopy experts Christoph Renner of the University of Geneva, in Switzerland, Steven De Feyter of the University of Leuven, in Belgium, and Paolo Samorì of the University of Strasbourg, in France (ACS Nano 2013, DOI: 10.1021/nn402414b; Langmuir 2013, DOI: 10.1021/la403546c). These experts’ research groups imaged a set of mixed thiol particles from Stellacci’s lab, analyzed the data, and found stripes.

Fabio Biscarini, a chemist at the University of Modena & Reggio Emilia, in Italy, later surveyed these new images with a method called power spectral density (PSD) analysis, a computational technique meant to remove any interpretation bias. He found periodic features that match the stripes Stellacci has seen.

Lévy and Moriarty say this new set of data is much better quality than previous ones, but they point out that the images look nothing like prior images recorded in Stellacci’s lab—the obvious ripples are gone, replaced with dots that Stellacci and coworkers connect to form stripes.

Others agree that the existence of stripes still isn’t clear. Stellacci and his collaborators did a good PSD analysis, says Vladimir V. Tsukruk of Georgia Institute of Technology, a materials scientist with a background in scanning-probe microscopy. “But stripes haven’t yet been proven.”

Given all the work he’s done finding outside collaborators to verify the existence of stripes, Stellacci says he believes his critics are trying to smear his reputation. He says that on Twitter, Lévy has compared him with Jan Hendrik Schön, infamous for committing fraud in his research. He finds this comparison unfair, given that he has never been found guilty of such misconduct. “My critics are after me, not the science.”

Lévy, Moriarty, and coworkers have also written a new article, “Critical Assessment of the Evidence for Striped Nanoparticles,” which examines Stellacci’s data old and new, STM and otherwise. They uploaded it to the preprint site arXiv on Dec. 24 of last year and submitted it to PLoS One shortly thereafter. With more than 240 comments, it is currently the most discussed paper on the online commenting site PubPeer.

In a Feb. 3 blog post on PhysicsFocus, Moriarty responded to Stellacci’s claims of being bullied. “Can I understand why Francesco might feel victimised? Yes,” he wrote. “As a fellow scientist, I can entirely appreciate that … a challenge to our research can feel like a direct criticism of ourselves.” But, he adds, research that is publicly funded should be debated in the open.

The Nottingham microscopist tells C&EN that another reason he’s taken the gloves off in this fight is that a former student of Stellacci’s, Predrag (Pedja) Djuranovic, came forward after Lévy began blogging, indicating that he had brought up concerns about the striped nanoparticle data with his adviser back in 2005.

At the time, Djuranovic was a new grad student at MIT tasked with studying whether a mixture of molecules formed stripes on semiconducting nanoparticles rather than the gold ones usually used in the lab. When he began to play around with the microscope, he says, he noticed that rippled features disappeared when he turned the gain down.

Concerned, he went back to basics and imaged particles with only one type of molecule coated onto them as well as an uncoated, roughened gold surface. Each time, he saw that he could produce ripples in the images just by turning up the STM gain.

Djuranovic claims he went to Stellacci a number of times to discuss his findings and that they had some heated arguments. Eventually, the student was put on a new project. Stellacci says it is his policy not to discuss former students and would not comment on Djuranovic’s story.


But Djuranovic couldn’t let things go. “It felt unethical not to raise the issue further,” Djuranovic says. So he discussed his concerns with his department head at MIT and eventually put them into writing for the university’s Office of the Vice President for Research. A few months later, an official investigation of Stellacci launched at MIT and Djuranovic left Stellacci’s research group.

MIT closed its review three years later, in 2008, finding Stellacci not guilty of academic misconduct. The university did, however, suggest that Stellacci should do additional work to substantiate his 2004 findings.

Stellacci tells C&EN that he was already working on a fuller statistical analysis of his data and addressed the suggestion when he published it in 2009 in the Journal of Scanning Probe Microscopy (DOI: 10.1166/jspm.2009.1004). No other students have come forward expressing concern.

For now, it seems Stellacci and his critics are at a stalemate. “They say they don’t see stripes,” Stellacci says. “It’s not only that I say I see stripes. Three microscopists who have imaged my particles see stripes. The referees of papers see stripes.”

The ETH Lausanne scientist also says he once offered to host Lévy in his lab to run experiments and get to the bottom of the issue. Lévy acknowledges the invitation but says it was made under the condition that he withdraw his 2012 Small paper.

Moriarty also says he’s extended an invite to Stellacci to visit his lab to no avail.

Paul S. Weiss, a pioneer in mixed molecule assembly on flat surfaces and editor of ACS Nano, says the debate has to end eventually. “The early data were inconclusive,” he says. “As a field, we’re still going. New tools will be developed and applied to sort out what the arrangements of mixed molecules on nanoparticles look like. Hopefully, we’ll discover new phenomena along the way.”  



This article has been sent to the following recipient:

Philip Moriarty (May 28, 2014 5:09 PM)
On a point of clarification --

Regarding the sentence "Moriarty also says he’s extended an invite to Stellacci to visit his lab to no avail", in fairness to Prof. Stellacci I should point out the following.

During 2013, a lengthy set of e-mails was exchanged between Prof. Stellacci and myself in an attempt to, for one, secure samples of striped nanoparticles for STM/AFM studies in Nottingham.

The invitation to visit our lab, however, was not made in one of these e-mails. Instead, it was made publicly on the PubPeer site in January 2014. See the penultimate paragraph of this comment:

As Prof. Stellacci has told me previously that he does not read blogs or post-publication peer review sites related to his work, it is highly likely that he was not aware of this invitation. My sincere apologies if this is indeed the case.

Nonetheless, the invitation still stands. As I said over at PubPeer, I would be very happy to welcome any of Prof. Stellacci's group (including Francesco himself) to Nottingham to collaborate on dynamic force microscopy imaging of the particles his team produces.

Finally, I would like to stress that the sentence in the article referring to the invitation to Prof. Stellacci arises purely from a lack of clarity on my part during an interview with the author, Lauren K Wolf. The author did not misrepresent my statements in any way.

Philip Moriarty
School of Physics and Astronomy
University of Nottingham

Nony-mouse (May 28, 2014 8:32 PM)
It's been 10 years (2004 to 2014) and the stripes still are not definitive, are questionable. The better you are at SPM, the more you distrust the stripes.

Part of the issue is chemists using finicky physics type instruments. As well as the incentives for invention and findings in the nano-chem field. And I say this as a chemist. But having seen the dynamics in the field from at least 1995.
Francesco Stellacci (May 29, 2014 7:25 AM)
Comment by Francesco Stellacci:

I feel the need to correct the record on this article, regarding my interaction with Raphael Lévy, as I find the statement “Lévy acknowledges the invitation [to my laboratory] but says it was made under the condition that he withdraw his 2012 Small paper.” to be incorrect and offensive.

As recently admitted in one of his pub-peer posts the first engagement I had with Dr. Lévy was in 2006 when I received -through Science- a critique to one of my papers. This critique involved no issues with STM. In 2009 at a IUPAC meeting in Glasgow I met Dr. Lèvy for the first time in my life. There I reached to him. He told me he was preparing a new paper to send to Nature Materials critiquing my STM work this time. I offered him to come to my laboratory at my expenses and to work with me on the issues and after to send his paper out. I also offered to maybe write such paper together. He refused, telling me that his priority was to first send his paper out. I tried to involve a third party to convince him to work with me, to no avail. At a public debate we had at the 2012 Gordon Conference on Noble Metal Nanoparticles he admitted receiving the office. This debate happened before the publication of his Small paper. As a consequence, the statement that Dr. Lèvy is quoted for in this article, is false, as in 2009 I could have never requested a 2012 publication withdrawn. My only request was to hold the initial submission of this paper so that we could have time to work and do experiments together.

Right after the wrong statement I just discussed I read “Moriarty also says he’s extended an invite to Stellacci to visit his lab to no avail.” I have to add that I have no record of Prof. Moriarty inviting me to his laboratory. I have been asked for samples, and the requests for samples have come in two separate times, both times my groups has started preparing the samples, as fully documented in my group. In both occasions, I believe that Prof. Moriarty has refused to wait for the needed time; but I do accept that he might see things differently. It is very important to note that in a personal email I find no record of an invitation to his laboratory. Given the large volume of personal emails and public posts on this issue, I admit that there could be an invitation somewhere consequently I have asked the author of this article (Lauren Wolf) to investigate. As far as I know after two days she has not heard from Prof. Moriarty yet.”
Philip Moriarty (May 29, 2014 7:09 PM)
Dear Francesco,

First, and in line with what Raphael says in a comment below, it's to your credit that you have engaged here in open discussion.

Although I have already posted a comment (May 28 2014, 5:29 pm) re. the invitation extended to you/your group to visit our lab here in Nottingham (in advance of your posting of your remarks), I would like to clarify a couple of points re. the final paragraph in your comment above (May 29 2014, 7:25 am) 'for the record'.

1. " I have been asked for samples, and the requests for samples have come in two separate times, both times my groups has started preparing the samples, as fully documented in my group."

This is incorrect. There were four separate requests for samples. I have the e-mail correspondence archived and would be very happy to send it to you (or post it here) if you would like to check. (I checked this correspondence in advance of speaking with Lauren). Each time I was told by you that the samples would be prepared and sent to us. Those samples never arrived.

2. " I believe that Prof. Moriarty has refused to wait for the needed time; "

We waited for eight months for samples to arrive from you, having been promised repeatedly that the samples were being prepared. In this period those samples were, as you have pointed out repeatedly, sent to three other 'independent' laboratories which were selected by you.

How much longer were we expected to wait?

As I've said to you by e-mail on many occasions, if it were me and the work of the Nottingham group was challenged, the very first people I would send the contested samples to would be our staunchest critics. This is how science should work.

3. "I have asked the author of this article (Lauren Wolf) to investigate. As far as I know after two days she has not heard from Prof. Moriarty yet.”

Just to get the 'chronology' on this in order...

I received an e-mail from Lauren on this matter at 22:01 on May 27 2014.

As you can see, my clarifying comment was submitted at 5:09 PM on May 28 2014.

Given that I had 161 exam scripts to mark over the last few days, I would argue that I gave the matter due diligence. Do you not agree?

Francesco Stellacci (May 29, 2014 7:34 AM)
I have read the comment of Prof. Moriarty after submitting my previous comment. I acknowledge his invitation whose existence I was not aware of. I do notice that this invitation was made after Prof. Moriarty submitted his paper on the issue to Plos One.
Philip Moriarty (May 29, 2014 7:11 PM)
Dear Francesco,

Again, on a matter of clarification. Could I ask whether you have read the discussion of our paper (i.e our critique of your work) at PubPeer?
Raphael Levy (May 29, 2014 11:44 AM)
The sentence Prof. Stellacci objects to is:

"The ETH Lausanne scientist also says he once offered to host Lévy in his lab to run experiments and get to the bottom of the issue. Lévy acknowledges the invitation but says it was made under the condition that he withdraw his 2012 Small paper."

I agree this could have been clearer. Lauren checked this sentence with me before publication and I regret not to have suggested a different formulation. Basically what is missing in this quote is the fact that the discussion happened in 2009, i.e. three years before the publication of the Small article. If a correction is needed, it would just be to insert "in 2009" after "invitation", and at the end of the sentence "which at that stage had been submitted to Nature Materials".

I agree with Prof. Stellacci that we met for the first time in Glasgow at the IUPAC meeting in Glasgow, 2-7 August 2009.

When we met, Stripy Nanoparticles Revisited had already been submitted to Nature Materials (it was submitted 17 July 2009). I told him immediately. He had not been informed yet by Nature Materials (they sent him the paper for a response on 18 August 2009).

The discussions we had in Glasgow were therefore about the submitted paper. Prof Stellacci tried to convince me to withdraw the submitted paper (not "hold the submission": it had been submitted) and even to do so immediately so that it would not be sent to referees.

In an email conversation that started during the conference itself, Prof Stellacci wrote: "Please consider that by Monday the paper may already be out" [Aug 5th].

If Prof. Stellacci thinks that it is useful to fully clarify the sequence of events, I am more than happy to share the full email trail by publishing it on my blog.

Although not relevant to the contested quote, I note that the word "admitted" in reference to the Science technical comment suggests that I may have denied this at some point. That is not the case and I cannot see any reason why I would have denied nor why I should feel any guilt for having sent a technical comment to Science. (I have published said technical comment in full at PubPeer: Divalent Metal Nanoparticles).

Finally, I welcome Prof. Stellacci decision to engage in the online discussion. As seen below it can be useful to clarify sequences of events, and maybe, even more interestingly, issues about the science and the scientific method. Since he quotes once again the 2009 the Journal of Scanning Probe Microscopy article, I would very much welcome his views about the re-use of figures in that article; see Data re-use update for details.
Francesco Stellacci (May 29, 2014 3:11 PM)
Reply to Raphael Levy

I thank Raphael Levy for his clarification. I do not have our email exchange anymore due to the fact that my computer was stolen a year ago.
I have no reason to doubt his words. So we can all agree that he should have corrected the sentence in article when he had the opportunity. At this point we have to conclude that the facts are that for two times he submitted very different comments on different parts of my work without informing me and without seeking any form of interaction prior to his submission. We agree that I reached to him. We also agree that in Glasgow I had no knowledge of his submission. I offered him to collaborate to find together a solution to the issue had he withdrawn his paper (that of course he could have in any case re-submitted right after a visit to my laboratory with a much stronger case, hence I believe that de facto I was asking to hold the paper). I apologize for not recalling these facts that happened so long ago more precisely.

Levy makes a point in underlying the world ‘admitted’ I used relative to the existence of his comment in Science. It appears to me -and I will leave this point to the reader- that his comment in Science contradicts his own statement in the 2012 (submitted in 2009) paper in Small where he states that he took interest in my work because of my engagement in the interaction of nanoparticles with biological material. We all agree his first engagement with me was on a paper that has no biology in it.

I am happy for the last paragraph of Levy’s comment as it allows me to make a key point. In a recent interview, later published in Science, I made the point that Levy’s attitude is that of on-line bullying (that is clearly not as harsh of the well-known bullying problem we face for teenagers, but that does take a toll). Immediately after, there has been a public attempt (for example in the PhysicsFocus blog post of Prof. Moriarty referenced in the article) to say that when talking about bullying I was referring to the public scrutiny of my work. This free interpretation of my words is far from my thought. As highlighted in this article in response to the scientific debate that occurred over my work, I engaged four eminent scientists to reproduce and re-analyze my work. In response I published, together with these scientists, three peer-reviewed papers, these papers were peer-reviewed during the heat of the debate. This has been my approach to engage the scientific part of this debate, I will keep addressing this debate with experiments and peer-reviewed papers. Never I said that this or any scientific debate (in any form) is a form of bullying.
Bullying to me is the last paragraph of Levy’s comment. Where he inserts –unrelated to the rest of the debate undergoing- a paragraph to link to his blog with accusations of misconduct. This is done, while knowing very well that he has brought up these accusations to my present and former institutions and that both institutions have concluded that I have not committed misconduct, that is I have not re-used images improperly. Bullying is this mixing of scientific arguments with all other possible arguments, so to aggressively tarnish a reputation. I have already explained in writing my position on those images, this explanation has not been asked to me by Levy neither prior nor after the misconduct committees had performed their duties.
Bullying for me is to receive an email by the Editor of ACS Nano relating accusations of data fabrication, and minutes after finding in Levy’s Twitter account comparisons to Schön. All of this happened, without having been asked for the raw data previously by Levy or any other. I want to point out that approximately an hour after these accusations were made I provided ACS Nano with the raw data and I did the same when a day or two later Prof. Moriarty asked me for a clarification of the issue. Bullying is forgetting of these and the many other issues like these that surround this debate, and hinting that it is the scientific debate what I consider bullying.
Raphael Levy (May 29, 2014 4:47 PM)
The blog I link to demonstrates evidence of reuse of figures between different published articles and in particular the one which you refer to above. This evidence does not depend on MIT or EPFL investigations of misconduct. The evidence can be checked in minutes by anyone who has access to the papers. Please send the explanation for the reuse of these figures and I will publish it on my blog immediately and prominently. I will also include links in all relevant blog posts.

Francesco Stellacci (May 30, 2014 6:51 AM)
Dear Raphael, as you are not ready to accept the conclusion of two investigations then what was the purpose of accusing me twice?
Once the scientific debate is over I will gladly provide all of the details on all of the non-scientific issues that were forced on me in the last year and a half.
Raphael Levy (May 30, 2014 5:35 PM)
The purpose is, and has been, to correct the scientific record. Nothing less and nothing more.

In terms of data re-use, the efforts have resulted in two corrections, one in PNAS and one in Nature Materials. The editor of those journals have eventually enforced their own rules.

In response to even more serious issues, the Editor of J Scann Probe Microsc responded:
“Unfortunately, publishing redundant results is too common nowadays, and there is virtually no way to control it.”
as reported here.

This remarkable response made it clear that the Editor of that journal had no intention to enforce any standard (the journal/publisher is not a member of the Committee on Publication Ethics, contrarily to Nature and PNAS).

It is unfortunate that Prof. Stellacci is not prepared to share his explanation of why the re-use of data and figures in JSPM is acceptable and does not require a correction/retraction.
Philip Moriarty (May 29, 2014 7:42 PM)

"I made the point that Levy’s attitude is that of on-line bullying (that is clearly not as harsh of the well-known bullying problem we face for teenagers, but that does take a toll)"

Again, just for the record, here's what you are quoted as saying in the Science article:

"I have been subject to chemical cyberbullying," Stellacci says. "I understand what kids that commit suicide go through."

So, when you say in your comment above that what you have faced "is clearly not as harsh as the well-known problem we face for teenagers", why exactly did you draw a very strong parallel with teenage suicide in your statement for the Science article?

As you know, I found this to be in poor taste (and said so in a comment underneath the Science article).

" Immediately after, there has been a public attempt (for example in the PhysicsFocus blog post of Prof. Moriarty referenced in the article) to say that when talking about bullying I was referring to the public scrutiny of my work."

It is rather important to note that I was certainly not the only person, nor the first, to suggest that your claim of cyber-bullying was misplaced. See Neuroskeptic's blog post . See also the set of tweets in the PhysicsFocus blog post to which you refer.

Those tweets were tweeted before my blog post was even written, let alone uploaded...

I want to point out that approximately an hour after these accusations were made I provided ACS Nano with the raw data and I did the same when a day or two later Prof. Moriarty asked me for a clarification of the issue.

In fairness to you, Francesco, I would like to confirm here that you did indeed clarify this particular issue with me extremely quickly.

It's a great shame, however, that this contrasts so much with the months it took for me to get the raw data for your earlier work from you, and which necessitated my having to contact the journal editors. (I still haven't received the image from the Adv. Materials paper I requested from you. But I don't suppose I ever will.)

Could I also remind you of the FakeRaphaZ blog (as described in this comment at PubPeer ?

Francesco Stellacci (May 30, 2014 7:12 AM)
Dear Philip,
I am honestly sorry you felt offended by my comparison in the Science article. I have made a clear distinction here. Yet I would ask you to respect the depth of my feelings. I hope you will not come and tell me what I think and/or feel.

I referenced your post about bullying because it is the only one referenced in the article above. I am happy that you have clarified the issue better.
As for the data sharing, after our first email exchange I sent you raw data within a day or two. When you asked for more data I decided to have this data analyzed by Prof. Biscarini first. Less than 24h after he finished his data analysis I sent you everything. I asked editors of informing you of this course of action but never checked if this really happened. Given your insistence in the period of time when the analysis was performed you may have not been properly informed.
As for the Advanced Materials images all of my record indicate that it was provided to you. I will check for the fourth time today to make sure.

Finally, let me conclude referring to your last sentence that in my opinion is indeed an act of bullying. You are hinting some form of an involvement of mine in the fake blog. As I have written to you, I have nothing to do with that blog in any form. Let me state clearly that I am willing to undergo a deep investigation of all of my online activities (call the NSA if you want) to prove that I have nothing to do with this or any other form of online activity that has happened related to this case. I did not write the fake blog, I did not ever write on Pub Peer, or on Raphael’s blog. As stated many times to you, the only blog I read is the Huffington Post, and in depth analysis of any computer I have ever had access to in my life will easily discover it. This is my only (and hopefully last) online engagement I have had in this case. As we have all agreed upon it was due to two sentences that should have been corrected by yourself and Raphael and were not.
nanonymous (May 30, 2014 1:15 AM)
Prof Stellacci,
I am glad to see you here engaging in the discussion. I hadn't heard about stripy until seeing Raphael's comments on chembark (a blog). The conversation in this thread has taken an ostensibly magnanimous tone, which I hope will facilitate the discussion.

I am not directly involved in the controversy, but since you are here I would love it if you could answer a few burning questions I've had since learning about this entire episode:

1) Do you not agree that the 2004 vs. 2013 images (show in this article) are categorically different? The 2004 images, even to someone like me who has never operated an STM but has experience with scientific imaging, just have that distinct odor of being an artefact (the lines are too regular, too smooth).

Being able to reproduce the 2004 images with validated imaging techqnique would essentially end this entire controversy. I feel it isn't fair for you to say that the images were "reproduced", the article makes it plainly clear to anyone that the 2004 and 2013 images are just not the same, in one the stripes are plainly visible and in the other they are not.

2)I've wondered why the samples have not been sent to Phillip, it looks like you are discussing that directly with him so I will follow that thread.

3)I'm puzzled by the plainly incorrect statement of the hairy ball theorem in the "divalent" paper. Has anyone else brought this up to you? The pubpeer thread that Raphael links to in his post provides details, but there seems to be an elementary error in logic, which leaves me very confused. The hairy ball theorem doesn't garauntee anything about coated nanoparticles.

4)You seem to have a proponent in the pubpeer threads on Raphel's paper, that you may not be aware of (a long page that is difficult to follow, but other commentors refer to her/him with monikers like "The Unreg"):

What do you think of some of the Unreg's defense of your work? Having engaged in discussion with that poster directly, I am quite certain that he/she/they were deliberately "trolling" with great tenacity. See the discussion on the hairy ball theorem on that page. Given the Unreg's tone, the "fakerapha" page I hope you can understand the position of an outside observer. It really looks quite fishy, but then again, it could just be some clown...but there are better places to clown around than articles about nanoparticles..
Brian R. Pauw (May 30, 2014 9:10 PM)
Leaving aside all details on the personal interactions, what strikes me most about this whole stripy nanoparticle debate is the following:

F. Stellacci explained observations of curious STM micrographs by hypothesising a particular segregation of the ligands on the surface (2004). A whole body of work is then based upon this STM analysis and interpretation being correct. However, there are quite a few features that are more difficult to explain with this hypothesis (for example the apparent alignment of the stripy features across multiple particles, and why the features are much less apparent in later work).

J. Stirling now (almost) published a reasonable alternative explanation for the features observed in STM. This explanation for the observations is much more straightforward and hypothesises, simulates and demonstrates a metrological source for the STM observations. In my eyes, this alternative explanation should be published and considered as an option.

What is odd is the big problems that have arisen when trying to publish this alternative explanation. I have come across quite a few articles in older (~1980) journals in which authors could openly criticise the science done by their colleagues. This led to interesting discourse which could genuinely advance science (and also often questioning the scientific understanding of the criticised colleagues), but is something we see less and less in later journals. The enormous resistance demonstrated here to publish even *one* critical work is disastrous to science, and that despite the obvious quality and rigour of the alternative explanation. If we no longer allow opposing views we are no better than religions.

I think it would be grossly shameful if we do not allow this critical view to be published on "equal footing" now (i.e. peer-reviewed publication). If we don't, we might wake up to find a newspaper article ten years form now entitled: "Researchers found not to understand their own instruments at all, chasing data ghosts for decades!". It would call for the abolishment of science because we obviously don't know what we are doing anymore and are just wasting money. This would only be strengthened by not having *any* critical work, demonstrating we are no longer capable to stand back and reevaluate knowledge in new light.
Philip Moriarty (May 31, 2014 2:49 AM)
Dear Francesco,

Thank you for the apology. I very much appreciate this. Similarly, it was never my intention to tell you what you should think/feel nor to deliberately cause hurt. If I have done this, I sincerely offer you my apologies.

There are a couple of points that need to be clarified/corrected in your response.

As for the data sharing, after our first email exchange I sent you raw data within a day or two. When you asked for more data I decided to have this data analyzed by Prof. Biscarini first. Less than 24h after he finished his data analysis I sent you everything.

For the most recent data (i.e. for the 2013 papers), I agree, and can confirm that the results related to the power spectral density analysis were indeed sent to Julian and myself very quickly. As discussed at length in the paper we have submitted to PLOS ONE, and over at PubPeer , we have significant qualms about the rigour of the PSD analysis.

But the data to which I was referring are not those from last year's papers. They're the images from papers in the period 2004 - 2012. See this post .

As for the Advanced Materials images all of my record indicate that it was provided to you. I will check for the fourth time today to make sure.

You indeed sent me an image. However, what I require, and as I've stated clearly previously, is the raw data for Fig. 5(d) of Kim et al., Adv. Mater. 24 3857 (2012). As you have taken Fig. 5(d) from a larger image (i.e. you've done an offline zoom) I'd very much appreciate it if you could highlight from just where on the larger image Fig. 5(d) is taken. What you've sent me thus far does not contain Fig. 5d.

As this image is from a relatively recent paper (2012) I hope that it will not take too long for you to find it. I am sure you understand why I would like to see the raw data in this case. Thanks.

You are hinting some form of an involvement of mine in the fake blog. As I have written to you, I have nothing to do with that blog in any form.

Francesco, I was not attempting to hint that you were involved in that fake blog and my genuine apologies if you felt I created this impression. You have indeed confirmed before that you had nothing to do with that blog and I take you at your word.

I flagged it up simply to point out that there are certainly those with a vested interest in the striped nanoparticle work -- and you have worked with a lot of people (PhD students, postdocs, collaborators) on those papers! -- who are more than willing to focus on the personal rather than the scientific.

Best wishes,

Philip Moriarty (May 31, 2014 3:02 AM)
Two recent comments posted elsewhere may be of interest to those following the striped nanoparticle debate.

1. Over at PubPeer , we have this unregistered submission:

"As a reviewer of one of the recent papers, I asked specifically for the authors to address the discrepancy between the stripes so easily visible in the original paper and the stripes that I struggled to see in the present work. It's disappointing that this wasn't really addressed."

This is a very intriguing comment. Francesco and co-workers could of course, and quite rightly, argue that because this is an unregistered submission at PubPeer we have no way of knowing whether the comment was indeed posted by a referee of the paper.

If we take the comment at face-value, however, it flags up an interesting issue.

2. Nanonymous posted this over at Raphael's blog. I don't think that the issue with posting the comment here at the C&EN site is so much related to moderation as to the "flakiness" of the website, so hopefully Nanonymous' comment will appear here soon. Just in case it doesn't, I've included the link here.
Nony-mouse (May 31, 2014 4:05 PM)
I think the FS defense of "bullying" just shows how the dynamic of social value of science (Nature papers, advancement, $$position, prestige, and shame) versus first priority being on discovering truth (getting into the technical debate).

It is going to look very bad in the end. Not that FS was wrong...but that he persisted for years. Drago showed the issues as a student in 2005. FS just didn't want to face that he had not made a nano invention.
Nanonymous (May 31, 2014 8:01 PM)
[Trying again to post and adjusting my original comment slightly]

Professor Stellacci,
The debate is of course primarily between Raphael, Phillip and you, but as a non-specialist I hope you can answer some of my questions. I've been enjoying reading the critical commentary on your work, and I understand it can be personally hurtful, but I want you to know that I don't bear any ill will to you and hope that you enjoy engaging in this discussion. I would thoroughly enjoy having my perspective (currently largely informed from posts on Raphael's blog) turned around completely.

On the "fakerapha" blog, your denial of involvement is emphatic, and I am certainly willing to trust your statements. Even though you are not invovled, I hope you can understand the speculation regarding the person authoring those those posts (and "The Unreg" on pubpeer), who seems to be an uninformed proponent of your work.

There do seem to be some hurt feelings, but the discussion has taken a magnanimous tone. I hope the air is clear enough now to address the scientific issues (the comments so far have focused on chronological ordering of events and emotions). Francesco can you clearly state his thoughts on:

1)The validity of the 2004 images and the *categorical* difference when compared to the 2013 images. You say that the images have been “reproduced”, this is plainly not the case. Could you ask Renner and De Feyter to provide a position statement on the validity of the 2004 images? This would be immensely informative to everyone as (at least) Phillip and you agree that Renner and De Feyter are outstanding.

2)Do you believe that Phillip might get the samples he has been apparently waiting 8 months for (ideally sent to other groups at the same time to *reproduce* the 2004 images with correct imaging technique)?

3)The validity of invoking the “hairy ball theorem” for the “Divalent” paper. This appears to be a fundamental mathematical misconception and the paper largely rests on it. The hairy ball theorem doesn't guarantee anything about special points on a thiol coated nanoparticle. I'm not a toplogist, but this comes across (to me) as nothing more than pseudomathematical reasoning. That sounds harsh, but that is precisely what it is, I would love to have someone explain it to me otherwise.

Philip Moriarty (June 2, 2014 10:03 AM)
Jon Cartwright has written a great article on the stripy nanoparticle controversy in this month's Physics World. "Nanoscience debate rages on", p.6 and p.7 of the June 2014 issue of the journal.

Not Famous (June 11, 2014 12:13 PM)
Is it possible to do any bulk scattering experiments on the stripey nanoparticles? If one of the ligands were partially deuterated I'd anticipate some contrast for a neutron scattering experiment.

Leave A Comment

*Required to comment