Cartilage-derived progenitor cells (CPCs) with the capability of self-renewal and multilineage differentiation have been identified as a suitable cell source for cartilage tissue regeneration. Despite decades of development in cell-delivery techniques, improved approaches are still required to maintain cell viability, provide a supportive environment, and implement appropriate cues to guide cartilage regeneration. This research work develops an injectable in situ gelation system as a cell carrier for CPCs to overcome cell-delivery drawbacks. The hydrogel was fabricated through a thiol–ene Michael addition reaction by cross-linking thiol-functionalized hyaluronic acid and hyperbranched poly(ethylene glycol) multi-acrylate macromer. The sol–gel transition, mechanical properties, microstructure, and degradation profile of the hydrogels were evaluated to ensure physical support, cell migration, and nutrient exchange within the system. Encapsulated CPCs maintained a high level of cell viability and proliferation property. Reverse transcription-quantitative real-time polymerase chain reaction confirmed that the extracellular matrix (ECM) secretion was enhanced under chondrogenic conditions. Moreover, the downregulated inflammation gene expression indicated the anti-inflammation ability of encapsulated CPCs. The study demonstrates that this rapid in situ forming hydrogel has excellent potential as a CPC delivery carrier by accelerating ECM production and retaining the phenotype and function of encapsulated CPCs.

中文翻译：

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软骨衍生的载有祖细胞的可注射水凝胶——一种软骨组织再生的方法

具有自我更新和多向分化能力的软骨源性祖细胞 (CPC) 已被确定为软骨组织再生的合适细胞来源。尽管细胞递送技术已有数十年的发展，但仍需要改进的方法来维持细胞活力、提供支持性环境并实施适当的提示来指导软骨再生。这项研究工作开发了一种原位注射剂凝胶系统作为 CPC 的细胞载体，以克服细胞递送的缺点。该水凝胶是通过硫醇官能化透明质酸和超支化聚（乙二醇）多丙烯酸酯大分子单体的交联，通过硫醇-烯迈克尔加成反应制备的。评估了水凝胶的溶胶-凝胶转变、机械性能、微观结构和降解曲线，以确保系统内的物理支撑、细胞迁移和营养交换。封装的 CPCs 保持了高水平的细胞活力和增殖特性。逆转录定量实时聚合酶链反应证实细胞外基质 (ECM) 分泌在软骨形成条件下增强。此外，下调的炎症基因表达表明封装的 CPCs 的抗炎能力。原位形成的水凝胶通过加速 ECM 的产生并保留封装 CPC 的表型和功能，具有作为 CPC 递送载体的巨大潜力。