Department of Chemistry and Nanoscience, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul, Korea.
Biomacromolecules. 2020 Aug 10;21(8):3176-3185. doi: 10.1021/acs.biomac.0c00623. Epub 2020 Jul 17.
How to control osteochondral differentiation of mesenchymal stem cells at a proper stage is a key issue for articular cartilage regeneration. To solve this problem, injectable scaffolds with different chemical functional groups were designed by introducing one equivalent of α-cyclodextrin (α-CD) carboxylate and α-CD phosphate along poly(ethylene glycol)-poly(l-alanine) (PEG-L-PA) block copolymers. Dynamic light scattering, transmission electron microscopy images, and two-dimensional NMR spectra indicated that the PEG-L-PA block copolymers formed inclusion complexes with α-CD derivatives. Aqueous solutions of PEG-L-PA block copolymers (P), α-CD carboxylate/PEG-L-PA block copolymers (PCC), and α-CD phosphate/PEG-L-PA block copolymers (PCP) underwent sol-to-gel transition as the temperature increased. The storage moduli of P, PCC, and PCP gels ranged from 1000 to 1300 Pa at 37 °C. Tonsil-derived mesenchymal stem cells (TMSCs) were incorporated in the gel during thermogelation of P, PCC, and PCP, which became the three-dimensional cell culture systems with different functional groups. After 21 days of incubation of TMSCs in the P, PCC, and PCP systems, the chondrogenic differentiation biomarker of type II collagen significantly increased in the P system, whereas the osteogenic biomarkers of osteocalcin and runt-related transcription factor 2 significantly increased in the PCP system. Both chondrogenic and osteogenic biomarkers were highly expressed in the PCC system. This study proved that thermogelling inclusion complex systems consisting of PEG-L-PA block copolymers and α-CD derivatives could be an excellent injectable matrix for fine-controlling osteochondral differentiation of mesenchymal stem cells.
如何在适当的阶段控制间充质干细胞的成软骨分化是关节软骨再生的关键问题。为了解决这个问题，通过在聚乙二醇-聚 L-丙氨酸（PEG-L-PA）嵌段共聚物中引入等当量的α-环糊精（α-CD）羧酸盐和α-CD 磷酸盐，设计了具有不同化学官能团的可注射支架。动态光散射、透射电子显微镜图像和二维 NMR 谱表明，PEG-L-PA 嵌段共聚物与α-CD 衍生物形成了包合物。PEG-L-PA 嵌段共聚物（P）、α-CD 羧酸盐/PEG-L-PA 嵌段共聚物（PCC）和α-CD 磷酸盐/PEG-L-PA 嵌段共聚物（PCP）的水溶液随着温度的升高经历了溶胶-凝胶转变。在 37°C 时，P、PCC 和 PCP 凝胶的储能模量范围为 1000 至 1300 Pa。在 P、PCC 和 PCP 的热凝胶化过程中，扁桃体衍生的间充质干细胞（TMSCs）被掺入凝胶中，这成为具有不同官能团的三维细胞培养系统。TMSCs 在 P、PCC 和 PCP 系统中孵育 21 天后，P 系统中 II 型胶原的软骨分化生物标志物显著增加，而 PCP 系统中骨钙素和 runt 相关转录因子 2 的成骨生物标志物显著增加。PCC 系统中同时高度表达软骨和成骨生物标志物。这项研究证明了由 PEG-L-PA 嵌段共聚物和α-CD 衍生物组成的热凝胶包合物系统可以成为精细控制间充质干细胞成骨软骨分化的优秀可注射基质。
