Retraction: Light-triggered nitric oxide release and targeted fluorescence imaging in tumor cells developed from folic acid-graft-carboxymethyl chitosan nanospheres.

[This retracts the article DOI: 10.1039/C4RA03034F.]. This journal is © The Royal Society of Chemistry.

The Royal Society of Chemistry hereby wholly retracts this RSC Advances article due to concerns with the reliability of the data in the published article.

The TEM image in Fig. 2a duplicates data in a number of other publications, but reported as different materials.[1-5]

The TEM image in Fig. 2c duplicates data in other publications, but representing different materials.[4,6] However, an additional particle has been copy and pasted into Fig. 2c of this RSC Advances article, which indicates that this image has been manipulated.

Given the number and significance of the concerns about the validity of the data, the findings presented in this paper are no longer reliable.

Rijun Gui opposes the decision to retract. Ajun Wan, Yalei Zhang, Huili Li and Tingting Zhao were contacted but did not respond.

Signed: Laura Fisher, Executive Editor, RSC Advances

Date: 21st September 2020