In situ cell recruitment is a promising regenerative medicine strategy with the purpose of tissue regeneration without stem cell transplantation. This chemotaxis-based strategy is aimed at ensuring a restorative environment through the release of chemokines that promote site-specific migration of healing cell populations. Stromal cell-derived factor-1α (SDF-1α) is a critical chemokine that can regulate the migration of mesenchymal stem cells (MSCs). Accordingly, here, SDF-1α-loaded microporous oligo[poly(ethylene glycol) fumarate]/bis[2-(methacryloyloxy)ethyl] phosphate composites (SDF-1α/OPF/BP) were engineered and probed. SDF-1α/OPF/BP composites were loaded with escalating SDF-1α concentrations, namely, 0 ng/ml, 50 ng/ml, 100 ng/ml, and 200 ng/ml, and were cocultured with MSC. Scratching assay, Transwell assay, and three-dimensional migration model were utilized to assess the migration response of MSCs. Immunofluorescence staining of Runx2 and osteopontin (OPN), ELISA assay of osteocalcin (OCN) and alkaline phosphatase (ALP), and Alizarin Red S staining were conducted to assess the osteogenesis of MSCs. All SDF-1α/OPF/BP composites engendered a release of SDF-1α (>80%) during the first four days. SDF-1α released from the composites significantly promoted migration and osteogenic differentiation of MSCs documented by upregulated expression of osteogenic-related proteins, ALP, Runx2, OCN, and OPN. SDF-1α at 100 ng/ml was optimal for enhanced migration and osteogenic proficiency. Thus, designed SDF-1α/OPF/BP composites were competent in promoting the homing and osteogenesis of MSCs and thus offer a promising bioactive scaffold candidate for on-demand bone tissue regeneration.

中文翻译：

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SDF-1α/OPF/BP复合材料增强间充质干细胞的迁移和成骨能力

原位细胞募集是一种有前途的再生医学策略，其目的是在没有干细胞移植的情况下进行组织再生。这种基于趋化性的策略旨在通过释放促进愈合细胞群特定部位迁移的趋化因子来确保恢复环境。基质细胞衍生因子-1 α (SDF-1 α ) 是一种关键的趋化因子，可以调节间充质干细胞 (MSC) 的迁移。因此，在这里，设计并探测了SDF-1 α负载的微孔低聚 [聚（乙二醇）富马酸酯]/双 [2-（甲基丙烯酰氧基）乙基]磷酸酯复合材料（SDF- 1α /OPF/BP）。SDF-1 α /OPF/BP 复合材料加载了不断增加的 SDF-1 α浓度，即 0 ng/ml、50 ng/ml、100 ng/ml 和 200 ng/ml，并与 MSC 共培养。划痕试验、Transwell 试验和三维迁移模型被用来评估 MSCs 的迁移反应。进行 Runx2 和骨桥蛋白 (OPN) 的免疫荧光染色、骨钙素 (OCN) 和碱性磷酸酶 (ALP) 的 ELISA 测定以及茜素红 S 染色以评估 MSCs 的成骨。所有 SDF-1 α /OPF/BP 复合材料在前四天都产生了 SDF-1 α (>80%)的释放。从复合材料中释放的SDF-1 α显着促进了 MSC 的迁移和成骨分化，这通过成骨相关蛋白、ALP、Runx2、OCN 和 OPN 的上调表达来证明。SDF- 1α100 ng/ml 是增强迁移和成骨能力的最佳选择。因此，设计的 SDF- 1α /OPF/BP 复合材料能够促进 MSCs 的归巢和成骨，从而为按需骨组织再生提供了一种有前景的生物活性支架候选物。