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NanoBubbles

ERC Synergy Grant project

CALL FOR PARTICIPATION – Replication in Bionanoscience

CALL FOR PARTICIPATION

Independent Replication of Carbon Quantum Dots Fluorescence and Cu²⁺ Sensing

1. Context and Scientific Background

The NanoBubbles replication project is an international initiative dedicated to the rigorous evaluation of the reproducibility of influential experimental results in nanoscience, through the use of pre-registered, peer-reviewed protocols and open science practices. It is part of NanoBubbles, an ERC Synergy project that focuses on the barriers to the correction of science.

The first replication of the NanoBubbles project has concluded with:

  • The publication of an OSF preprint in August 2025¹, and,
  • Its peer review and formal recommendation by Peer Community In Registered Reports in October 2025².

This replication targeted a highly cited article³ reporting the intracellular detection of copper ions using electrochemically synthesised carbon quantum dots (CQDs) functionalised with an AE-TPEA ligand capable of chelating Cu²⁺ ions. Using a pre-registered and peer-reviewed protocol⁴, closely aligned with the original publication and further specified following experimental experience and reviewer feedback⁵, the NanoBubbles replication team obtained results that diverge substantially from the original findings. In particular:

  • The measured quantum yield of CQDs was approximately 20 times lower than reported in the original article, and
  • No fluorescence dependence on Cu²⁺ concentration was observed, precluding the use of the material as a copper sensor under the tested conditions.

The authors of the original article contest these findings. In a private communication with the Editor of Angewandte Chemie—shared with the NanoBubbles team with authorisation—they state that they were able to reproduce their original results without difficulty.

2. Objectives of the Call

The present call aims to assess whether the replication process itself, based on detailed protocols, preregistration, and full transparency, enables the production of robust and reproducible results.
More specifically, the objectives are:

  • To independently verify the fluorescent properties of electrochemically produced carbon quantum dots,
  • To assess the Cu²⁺-sensing capability of AE-TPEA-functionalised CQDs, and
  • To evaluate the reproducibility of the NanoBubbles replication results through independent experimental repetition.

Given the central role of CQDs in the nanoscience literature—where thousands of publications rely on their reported properties—this work addresses a critical methodological and epistemic issue for the field.

3. Scope of the Work

Selected laboratories will be required to reproduce the experiments conducted by the NanoBubbles replication team, strictly following the registered report protocol and documenting all procedures in detail. The tasks include:

  1. Synthesis of carbon quantum dots (CQDs) and AE-TPEA-functionalised CQDs (C-TPEA).
  2. Measurement of absorbance and fluorescence spectra of both samples.
  3. Acquisition of FTIR spectra for both samples.
  4. Determination of the quantum yield of CQDs.
  5. Measurement of C-TPEA fluorescence as a function of Cu²⁺ concentration.
  6. Acquisition of electron microscopy images of both samples.
  7. Deposition of all raw data on Zenodo, with complete and standardised metadata.
  8. Preparation and sharing of samples to be analysed by an independent, internationally recognised characterisation platform, which will replicate steps 2–7.

4. Financial and Logistical Support

The NanoBubbles project will:

  • Fund or directly procure all required chemicals,
  • Fund transportation costs to the independent characterisation platform.

Additional reasonable and duly justified costs (e.g. access to specific instrumentation) may be considered on a case-by-case basis.
The expected duration of the work is 3 to 5 months.

5. Selection Procedure

Applications will be evaluated by the NanoBubbles Scientific Advisory Board, which operates independently from the NanoBubbles replication team.
Selection criteria include:

  • demonstrated expertise in nanochemistry, physical chemistry, or related fields,
  • access to the required experimental and characterisation facilities,
  • commitment to open science practices and rigorous documentation.

6. Dissemination of Results

Upon completion of the experimental work and characterisation, the Advisory Board will coordinate the preparation of a joint scientific publication with the selected laboratories;

Members of the NanoBubbles research team will not be co-authors of the resulting article.

All data and materials will be made publicly available in accordance with open science principles.

7. Timeline

To apply, fill this online form.

Deadline for applications : 06 March 2026 – 17 h 

 

8. Contacts

For scientific question about the call, its eligibility with regard to the call criteria : c.menard@ibmc-cnrs.unistra.fr

For administrative and financial question or submission : nikolina.rakotoarivony@univ-paris13.fr

9. Governance

NanoBubbles Replication Team

  • Mustafa Gharib
  • Maha Said
  • Raphaël Lévy

Scientific Advisory Board

  • Cécilia Menard-Moyon (Strasbourg, France), Chair
  • Arwyn Jones (Cardiff, United Kingdom)
  • Georgina Such (Melbourne, Australia)
  • Wolfgang Parak (Hamburg, Germany)
  • Olavo Amaral (Rio de Janeiro, Brazil)

10. References

  1. M. Gharib, M. Said, T. Pons, N. Hondow, S. Zrig, R. Lévy, “Failed, Aborted Replication of “Carbon-Dot-Based Dual-Emission Nanohybrid Produces a Ratiometric Fluorescent Sensor for In Vivo Imaging of Cellular Copper Ions” OSF preprint; 2025, DOI: 10.31219/osf.io/2x3hv_v3 [this article will also appear in Royal Society Open Science early March at this DOI].
  2. E. Linnane, C. Menard-Moyon, and Y. Yamada, “Unsuccessful replication of cellular copper ion imaging using carbon dots” 2025 Peer Community in Registered Reports, 101070.
  3. A. Zhu, Q. Qu, X. Shao, B. Kong, Y. Tian, “Carbon-Dot-Based Dual-Emission Nanohybrid Produces a Ratiometric Fluorescent Sensor for In Vivo Imaging of Cellular Copper Ions” Angew. Chem. Int. Ed. 2012, 51, 7185 –7189
  4. M. Said, M. Gharib, S. Zrig, R. Lévy, “Replication of “Carbon-Dot-Based Dual-Emission Nanohybrid Produces a Ratiometric Fluorescent Sensor for In Vivo Imaging of Cellular Copper Ions” OSF preprint; 2023, DOI: 10.31219/osf.io/kf9qe
  5. E. Linnane, Y. Yamada, “Replicating, Revising and Reforming: Unpicking the Apparent Nanoparticle Endosomal Escape Paradox.” Peer Community in Registered Reports, 2024, id=610