Developing multifunctional hydrogels with good mechanical properties, tissue-adhesiveness, self-healing properties and antioxidant, blood clotting and antibacterial properties is highly desirable for biomedical applications. In this study, a series of multifunctional chitosan-based double cross-linked hydrogels were prepared using a facile method based on quaternized chitosan (QCS) and polyacrylamide (PAM) using polydopamine (PDA) as a novel connecting bridge. Investigation on the content of dopamine (DA) and QCS revealed that the catechol-mediated interactions played an important role in the hydrogel properties. Results showed that the hydrogel exhibited the best mechanical properties when QCS = 12 wt% and DA = 0.4 wt%. Tensile and compressive strength was 13.3 kPa and 67.8 kPa, respectively, and the hydrogel presented strong and repeatable tissue-adhesiveness (27.2 kPa) to porcine skin, as well as good stretchability (1154%). At room temperature, the hydrogel exhibited high self-healing efficiency (90% after 2 h of healing). Antibacterial test results showed that the hydrogel killed 99.99% S. aureus and E. coli. Moreover, the vaccarin-loaded hydrogel exhibited a pH-responsive drug release profile with superior cytocompatibility compared to the pure hydrogel. In summary, this strategy combined double cross-linking and catechol-mediated chemistry to shed new light on the fabrication of novel multifunctional hydrogels with desirable mechanical properties, strong tissue adhesiveness and self-healing abilities.

对于生物医学应用，非常需要开发具有良好机械性能，组织粘附性，自愈性能和抗氧化剂，血液凝结和抗菌性能的多功能水凝胶。在这项研究中，使用聚多巴胺（PDA）作为新型连接桥，使用基于季铵化壳聚糖（QCS）和聚丙烯酰胺（PAM）的简便方法，制备了一系列基于壳聚糖的多功能双交联水凝胶。对多巴胺（DA）和QCS含量的研究表明，邻苯二酚介导的相互作用在水凝胶性质中起重要作用。结果表明，当QCS = 12 wt％和DA = 0.4 wt％时，水凝胶表现出最佳的机械性能。拉伸强度和抗压强度分别为13.3 kPa和67.8 kPa，并且水凝胶对猪皮肤呈现出强而可重复的组织粘附性（27.2 kPa），以及良好的拉伸性（1154％）。在室温下，水凝胶显示出很高的自我修复效率（愈合2小时后达到90％）。抗菌测试结果表明，水凝胶杀死了99.99％的金黄色葡萄球菌和大肠杆菌。此外，与纯水凝胶相比，负载痘苗蛋白的水凝胶显示出具有pH响应的药物释放曲线，具有优异的细胞相容性。总之，该策略结合了双重交联和邻苯二酚介导的化学作用，为新型多功能水凝胶的制备提供了新的亮点，该新型水凝胶具有所需的机械性能，强大的组织粘附性和自愈能力。