Correction: An injectable hyaluronic acid/PEG hydrogel for cartilage tissue engineering formed by integrating enzymatic crosslinking and Diels-Alder "click chemistry"(Polymer Chemistry (2014) 5 (1082–1090) DOI: 10.1039/C3PY00869J)

The authors regret that the incorrect images were used in Fig. 8A, B and C to represent three different culture time points. The correct version of Fig. 8 is shown below. (Figure Presented). In order to further prove the authenticity of the experimental data, additional supplementary information is also provided here. Fig. S1(A–C) are the original images generated using fluorescence microscopy. Because of the high cell culture density encapsulated in the hydrogel (3 × 106 cells per ml), the phenomenon of cell proliferation after 1 d, 3 d and 7 d culture cannot be distinguished and observed especially in low brightness. Therefore, the image brightness was increased to 20% and 40% to make sure that more cells (marked with green fluorescence) could appear in the image and so that the cell proliferation after different culture days could be observed by the naked eye (Fig. S1(D–I)). In addition, a CCK-8 assay is an efficient and quantitative way to prove the cell proliferation. Here, the detailed data are also provided in Table S1 to further supplement the data shown in Fig. 8D. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.