Failed, aborted replication of ‘Carbon-dot-based dual-emission nanohybrid produces a ratiometric fluorescent sensor for in vivo imaging of cellular copper ions’

Abstract This study presents the results of a replication effort aimed at reproducing key findings from the 2012 article ‘Carbon-dot-based dual-emission nanohybrid produces a ratiometric fluorescent sensor for in vivo imaging of cellular copper ions’ by Zhu et al. The original study claimed that carbon quantum dots (CQDs) functionalized with N-(2-aminoethyl)-N,N′,N′-tris(pyridine-2- ylmethyl)ethane-1,2-diamine (AE-TPEA) (CQDs-TPEA) and their hybrid with CdSe/ZnS quantum dots (CdSe@C-TPEA) exhibited ratiometric fluorescence quenching upon exposure to Cu2+ ions, enabling their application as a dual-emission sensor for intracellular Cu2+ imaging. Despite closely following the described synthesis and characterization protocols, we were unable to reproduce the Cu2+-induced fluorescence quenching, undermining the primary claim of the original study and making it impossible to pursue the investigation in live cells. Furthermore, upon close examination of the original data, concerns regarding spectral anomalies and potential inconsistencies were raised, prompting us to abort the replication study. This Registered Report has been officially endorsed by Peer Community In Registered Reports: https://doi.org/10.24072/pci.rr.101070.