Antibacterial and conductive injectable hydrogels based on quaternized chitosan-graft-polyaniline/oxidized dextran for tissue engineering

Biomaterials with injectability, conductivity and antibacterial effect simultaneously have been rarely reported. Herein, we developed a new series of in situ forming antibacterial conductive degradable hydrogels using quaternized chitosan (QCS) grafted polyaniline with oxidized dextran as crosslinker. The chemical structures, morphologies, electrochemical property, conductivity, swelling ratio, rheological property, in vitro biodegradation and gelation time of hydrogels were characterized. Injectability was verified by in vivo subcutaneous injection on a Sprague Dawley rat. The antibacterial activity of the hydrogels was firstly evaluated employing antibacterial assay using Escherichia coli and Staphylococcus aureus in vitro. The hydrogels containing polyaniline showed enhanced antibacterial activity compared to QCS hydrogel, especially for hydrogels with 3 wt% polyaniline showing 95 kill% and 90 kill% for E. coli and S. aureus, respectively. Compared with QCS hydrogel, the hydrogels with 3 wt% polyaniline still showed enhanced antibacterial activity for E. coli in vivo. The adipose-derived mesenchymal stem cells (ADMSCs) were used to evaluate the cytotoxicity of the hydrogels and hydrogels with polyaniline showed better cytocompatibility than QCS hydrogel. The electroactive hydrogels could significantly enhance the proliferation of C2C12 myoblasts compared to QCS hydrogel. This work opens the way to fabricate in situ forming antibacterial and electroactive degradable hydrogels as a new class of bioactive scaffolds for tissue regeneration applications. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

同时具有可注射性、导电性和抗菌作用的生物材料鲜有报道。在此，我们以氧化葡聚糖为交联剂，利用季铵化壳聚糖（QCS）接枝聚苯胺开发了一系列新型原位形成的抗菌导电可降解水凝胶。对水凝胶的化学结构、形貌、电化学性能、导电性、溶胀率、流变性能、体外生物降解性和凝胶化时间进行了表征。通过在Sprague Dawley大鼠体内皮下注射验证了其可注射性。首先通过体外对大肠杆菌和金黄色葡萄球菌的抗菌试验评估了水凝胶的抗菌活性。与QCS水凝胶相比，含聚苯胺的水凝胶显示出更强的抗菌活性，特别是含3 wt%聚苯胺的水凝胶对大肠杆菌和金黄色葡萄球菌的杀灭率分别为95%和90%。与QCS水凝胶相比，含3 wt%聚苯胺的水凝胶在体内对大肠杆菌仍显示出更强的抗菌活性。采用脂肪来源的间充质干细胞（ADMSCs）评估水凝胶的细胞毒性，含聚苯胺的水凝胶比QCS水凝胶显示出更好的细胞相容性。与QCS水凝胶相比，电活性水凝胶能显著促进C2C12成肌细胞的增殖。这项工作为制备原位形成的抗菌和电活性可降解水凝胶作为一类用于组织再生应用的新型生物活性支架开辟了道路。（C）2015 Acta Materialia Inc. 由Elsevier Ltd.出版。保留所有权利。