Temenoff Johnna S, Park Hansoo, Jabbari Esmaiel, Conway Daniel E, Sheffield Tiffany L, Ambrose Catherine G, Mikos Antonios G
Department of Bioengineering, Rice University, Houston, Texas 77251, USA.
Biomacromolecules. 2004 Jan-Feb;5(1):5-10. doi: 10.1021/bm030067p.
A novel polymer, oligo(poly(ethylene glycol) fumarate) (OPF), cross-linked with a thermal radical initiation system has recently been developed in our laboratory as an injectable, biodegradable cell carrier for regeneration of orthopaedic tissues. The cross-linking, swelling, and degradative properties of hydrogels prepared from OPF with poly(ethylene glycol) of two different chain lengths were assessed. The two OPF types had similar gelation onset times ( approximately 3.6 min) but, when cross-linked for 8 min at 37 degrees C, exhibited significantly different swelling characteristics (fold swelling: 17.5 +/- 0.2 vs 13.4 +/- 0.4). Rat marrow stromal cells (MSCs) were then directly combined with the hydrogel precursors and encapsulated in a model OPF formulation at approximately 14 million cells/mL, cultured in vitro in the presence of osteogenic supplements (dexamethasone), and monitored over 28 days via histology. MSC differentiation in these samples (6 mm diameter x 0.5 mm thick before swelling), as determined by Von Kossa staining for calcified matrix, was apparent by day 21. At day 28, mineralized matrix could be seen throughout the samples, many microns away from the cells. These experiments strongly support the usefulness of thermally cross-linked OPF hydrogels as injectable cell carriers for bone regeneration.
一种新型聚合物，聚（乙二醇）富马酸酯寡聚物（OPF），与热自由基引发体系交联，最近在我们实验室被开发为一种可注射、可生物降解的细胞载体，用于骨科组织再生。评估了由OPF与两种不同链长的聚乙二醇制备的水凝胶的交联、溶胀和降解特性。两种OPF类型具有相似的凝胶化起始时间（约3.6分钟），但在37℃交联8分钟时，表现出显著不同的溶胀特性（溶胀倍数：17.5±0.2对13.4±0.4）。然后将大鼠骨髓基质细胞（MSCs）直接与水凝胶前体混合，并以约1400万个细胞/毫升的浓度封装在模型OPF制剂中，在成骨补充剂（地塞米松）存在下进行体外培养，并通过组织学监测28天。通过对钙化基质的Von Kossa染色确定，这些样品（溶胀前直径6毫米×厚0.5毫米）中的MSC分化在第21天很明显。在第28天，整个样品中都可以看到矿化基质，距离细胞有许多微米远。这些实验有力地支持了热交联OPF水凝胶作为骨再生可注射细胞载体的实用性。
