Department of Chemistry and Nano Science, Ewha Global Top 5 Research Program, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
Biomacromolecules. 2013 Sep 9;14(9):3256-66. doi: 10.1021/bm400868j. Epub 2013 Aug 19.
Poly(ethylene glycol)-b-poly(L-alanine) (PEG-L-PA)s with L-PA molecular weights of 620, 1100, and 2480 Da and a fixed molecular weight of PEG at 5000 Da were synthesized to compare the thermosensitive behavior, and to investigate their potential as a three-dimensional (3D) culture matrix of adipose-tissue-derived stem cells (ADSCs). The sol-to-gel transition temperature and the concentration ranges where the transition was observed decreased as the L-PA molecular weight increased. ADSCs were cultured in the 3D matrixes of in situ formed PEG-L-PA hydrogels, which were produced by increasing the temperature of cell-suspended PEG-L-PA aqueous solutions. The spherical morphology was maintained in the PEG-L-PA hydrogel, while the cells underwent fibroblastic morphological changes in the Matrigel over 14 days of incubation. ADSCs exhibited high expression of type II collagen in the PEG-L-PA thermogel. In addition, they also moderately expressed the biomarker of myogenic differentiation factor 1 as the same mesodermal lineages, as well as the type III β-tubulin as a cross-differentiation biomarker. Similar to the in vitro study, the ADSCs predominantly exhibited chondrogenic biomarkers in the in vivo study. The study demonstrates that the polypeptide thermogel of PEG-L-PA is promising as a 3D culture matrix of ADSCs and as an injectable tissue engineering biomaterial.
聚乙二醇-聚 L-丙氨酸（PEG-L-PA）的 L-PA 分子量分别为 620、1100 和 2480Da，PEG 的固定分子量为 5000Da，我们合成这些共聚物来比较其温敏行为，并研究其作为脂肪组织来源干细胞（ADSCs）的三维（3D）培养基质的潜力。随着 L-PA 分子量的增加，溶液到凝胶的转变温度和观察到转变的浓度范围降低。ADSCs 被培养在原位形成的 PEG-L-PA 水凝胶的 3D 基质中，这是通过提高细胞悬浮 PEG-L-PA 水溶液的温度来实现的。在 PEG-L-PA 水凝胶中，细胞保持球形形态，而在 Matrigel 中孵育 14 天后，细胞发生成纤维细胞形态变化。ADSCs 在 PEG-L-PA 温敏凝胶中高表达 II 型胶原蛋白。此外，它们还适度表达成肌分化因子 1 的生物标志物，作为相同的中胚层谱系，以及 III 型 β-微管蛋白作为交叉分化的生物标志物。与体外研究类似，ADSCs 在体内研究中主要表现出软骨生成标志物。该研究表明，PEG-L-PA 的多肽温敏凝胶有望成为 ADSCs 的 3D 培养基质和可注射组织工程生物材料。
