Researchers are struggling to reproduce a paper that showed quantum dots could detect copper ions inside living cells. Now they're calling all nanoscientists for help.
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The researchers, based in the Netherlands and France, are trying to replicate their landmark 2012 study that claimed fluorescent quantum dots can detect copper ions inside living cells, as part of one of the first major efforts in the physical sciences to tackle the reproducibility crisis.
They are offering both funding and resources in exchange for a few months of collaborative work to rigorously reassess the original findings.
We are trying to use replication as a tool to solve a controversy or, you know, to get closer to the truth.
Raphaël Lévy, Physicist, Sorbonne Paris North University
Levy also co-leads NanoBubbles, a European initiative that studies self-correction in science.
The project, named after the bubbles of misinformation that can form when poor science goes untreated, issued a call for support on February 11th, 2026. The call comes as other study organizations in psychology and the social sciences prepare to provide updates on their own large-scale replication initiatives, motivated by the enormous number of scientific results that cannot be replicated when other people conduct the same experiments.
Sometimes these trials ensure that the data given in published papers support the results and conclusions. In other circumstances, they restart the experiments from scratch. Last year, for example, a large-scale reproducibility project in Brazil attempted but failed to verify dozens of biomedical findings.
Lévy, one of four researchers leading the NanoBubbles project, which is funded by a €8-million (US$9.5-million) grant from the European Research Council, wants laboratories to re-examine a 2012 study that suggested small, fluorescent carbon nanoparticles may detect copper ions within living cells.
This might be medically significant because excessive copper levels are associated with diseases, including cancer and neurodegenerative disorders. The study, led by Yang Tian, a chemist at Tongji University in Shanghai, China, is part of a larger research effort to develop modified nanoparticles for imaging, diagnostics, and drug delivery.
After pre-registering their intentions, the NanoBubbles team attempted and failed to replicate the findings in the research.
I was really surprised, because in the published protocol, the fluorescence of the particles decreased when the concentration of the target increased, but in our experiments, it just stayed the same.
Mustafa El Gharib, Nanoscientist, Sorbonne Paris North University
Nature contacted Tian but received no response.
Field Variations
There are several reasons why work in this field might fail to replicate, according to Wolfgang Parak, a physicist at the University of Hamburg in Germany who is on the NanoBubbles advisory board but was not involved in Gharib’s investigations.
For example, Parak stated that one of his synthesis processes proved difficult to replicate after relocating his lab from the United States to Europe.
Surface chemistry is extremely sensitive to small impurities.
Wolfgang Parak, Physicist, University of Hamburg
Reagents in different countries may vary in contamination levels. Another issue is that experimental methods may not always provide adequate step descriptions. So, any study that identifies critical points in procedures and shows how to enhance them is beneficial.
Parak believes the NanoBubbles replication was done effectively.
They really measured everything very carefully and used state-of-the-art techniques.
Wolfgang Parak, Physicist, University of Hamburg
Levy's team revealed the findings in a preprint submitted last year, which is set to be published in Royal Society Open Science.