1 Supporting Information Preserving the Adhesion of Catechol–Conjugated Hydrogels by Thiourea–Quinone Coupling Yang J. Xu, Kongchang Wei, Pengchao Zhao, Qian Feng, Chun Kit K. Choi and Liming Bian* Electronic Supplementary Material (ESI) for Biomaterials Science. This journal is © The Royal Society of Chemistry 2016