Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX3 7DQ, United Kingdom.
Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London WC1X 8LD, United Kingdom.
Biomed Mater. 2020 Jul 20;15(5):055005. doi: 10.1088/1748-605X/ab8c43.
In this work, a novel enzymatically crosslinked injectable hydrogel comprising hyaluronic acid (HyA), dopamine (DA), and 3-(4-hydroxyphenyl) propionic acid (HPA) conjugates was successfully developed. To the best of our knowledge, it is the first time that HPA is conjugated to a HyA-based backbone. In situ hydrogelation of HyA-DA-HPA occurred in the presence of hydrogen peroxide (HO) as an oxidant and horseradish peroxidase (HRP) as a catalyst. Proton nuclear magnetic resonance and Fourier transform infrared spectroscopy were used to characterize the chemical reactions between HyA, DA, and HPA. Gel formation completed between 3 s to 5 min depending on the concentrations of polymer, HRP, and HO. Crosslinked HyA-DA-HPA gels acquired storage moduli ranging from ∼100 Pa to ∼20 000 Pa (at f = 2000 rad s). Biocompatibility of the hydrogels was examined with human mesenchymal stem cells (hMSCs) and human induced pluripotent stem cell-derived neural stem cells. The hydrogels made of 2.0 w/v% HyA-DA-HPA hydrogels, 0.24 U ml HRP and ≤ 0.5 µmol ml HO were found biocompatible with hMSCs cultured on and encapsulated within the hydrogels. Since HyA serves as a backbone of the extracellular matrix in the central nervous system (CNS) and DA acquires the ability to restore dopaminergic neurons, use of this injectable HyA-DA-HPA hydrogel for stem cell transplantation is a potential treatment strategy for CNS repair and regeneration.
在这项工作中，成功开发了一种新型的酶交联可注射水凝胶，包含透明质酸（HyA）、多巴胺（DA）和 3-（4-羟苯基）丙酸（HPA）缀合物。据我们所知，这是第一次将 HPA 与基于 HyA 的主链连接。在过氧化物酶（HRP）作为催化剂和过氧化物酶（HRP）作为催化剂的存在下，HyA-DA-HPA 发生原位水凝胶化。使用质子核磁共振和傅里叶变换红外光谱来表征 HyA、DA 和 HPA 之间的化学反应。凝胶形成时间取决于聚合物、HRP 和 HO 的浓度，范围从 3 秒到 5 分钟。交联的 HyA-DA-HPA 凝胶获得的储能模量范围为 100 Pa 到 20,000 Pa（在 f = 2000 rad s）。用人骨髓间充质干细胞（hMSCs）和人诱导多能干细胞衍生的神经干细胞来检测水凝胶的生物相容性。发现由 2.0 w/v% HyA-DA-HPA 水凝胶、0.24 U ml HRP 和 ≤ 0.5 µmol ml HO 制成的水凝胶与在水凝胶上培养和封装的 hMSCs 具有生物相容性。由于 HyA 作为中枢神经系统（CNS）细胞外基质的主链，并且 DA 获得了恢复多巴胺能神经元的能力，因此这种可注射的 HyA-DA-HPA 水凝胶用于干细胞移植是 CNS 修复和再生的潜在治疗策略。
