Correction to: Nature Nanotechnology https://doi.org/10.1038/nnano.2016.280, published online 9 January 2017.

In the version of this Article originally published, incorrect images were used for columns 4–6 in Fig. 4a. Also, the fluorescent scale of columns 1–3 was inconsistent with the others, and the scale bar was missing. The original and corrected panels of Fig. 4a are shown below. This does not affect the text or the conclusions of the paper.

Fig. 4a
figure 4

Original and Corrected.

Supplementary Information Fig. 40, shown below, is a new figure that is an independently repeated result related to Fig. 4a.

Supplementary Fig. 40
figure 40

Representative confocal images of the intracellular O2 level indicator [Ru(dpp)3]Cl2-stained MCF-7 cells after treatments in different culture media of pH = 7.4 or 6.5 and co-incubated with varied concentrations of MS NPs (0, 2, 5 and 10 mM) for 2 h. Scale bars, 50 µm. Note that the status of cell adherence is a little different between the two independent experiments, but it doesn’t affect the qualitative fluorescence assessment. The increased red fluorescence indicates a decrease in the intracellular oxygen level. The result further confirms that the acidity-activated deoxygenating effect of MS NPs on the cells is repeatable.