Scientific Reports 6: Article number: 24172; published online: 13 April 2016; updated: 22 June 2016

This Article has been retracted by the Editors and Publishers of Scientific Reports. Following online criticisms of the published paper, an investigation at the journal has confirmed the manipulation and duplication of data and a level of image processing that is not compliant with the journal’s policies on image data integrity in figures 1–3, 6, 7, 10 and 12. Versions of figures 1–11 and large sections of the text had also previously been published1,2.

All authors acknowledge these issues and agree to the retraction of the Article.