Liu Shao Qiong, Ee Pui Lai Rachel, Ke Chyan Ying, Hedrick James L, Yang Yi Yan
Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, Singapore.
Biomaterials. 2009 Mar;30(8):1453-61. doi: 10.1016/j.biomaterials.2008.11.023. Epub 2008 Dec 20.
In this study, biodegradable PEG-peptide hydrogels have been synthesized using Click chemistry. A series of Arg-Gly-Asp (RGD) containing peptides were prepared via a solid phase synthesis approach, which were further functionalized with azide to yield peptide azide or peptide diazide. A tetra-hydroxy terminated 4-arm PEG was functionalized with acetylene and was reacted with peptide azide/diazide and/or PEG diazide to produce hydrogels via a copper mediated 1,3-cycloaddition (Click chemistry) generating a triazole linkage as the networking forming reaction. The gelation time ranged from 2 to 30 min, depending on temperature, catalyst and precursor concentration, as well as peptide structure. The resulting hydrogels were characterized by swelling, viscoelastic properties and morphology as well as their ability for cell attachment and proliferation. Hydrogels cross-linked by peptide diazide yielded higher storage modulus (G') with shorter spacers between azide groups. As expected, the swelling degree decreased while the G' increased with increasing the concentration of the precursors as a result of increased cross-linking density. Primary human dermal fibroblasts were used as model cells to explore the possibility of using the RGD peptide hydrogels for cell-based wound healing. The attachment and proliferation of the cells on the hydrogels were evaluated. The RGD peptide hydrogels synthesized with a peptide concentration of 2.7-5.4mm achieved significantly improved cell attachment and greater cell proliferation rate when compared to the hydrogels without RGD peptides. These hydrogels may provide a platform technology to deliver cells for tissue repair.
在本研究中，利用点击化学合成了可生物降解的聚乙二醇 - 肽水凝胶。通过固相合成方法制备了一系列含精氨酸 - 甘氨酸 - 天冬氨酸（RGD）的肽，进一步用叠氮化物进行功能化，得到肽叠氮化物或肽二叠氮化物。用乙炔对四羟基封端的四臂聚乙二醇进行功能化，并使其与肽叠氮化物/二叠氮化物和/或聚乙二醇二叠氮化物反应，通过铜介导的1,3 - 环加成反应（点击化学）生成水凝胶，形成三唑键作为网络形成反应。凝胶化时间为2至30分钟，具体取决于温度、催化剂、前体浓度以及肽的结构。对所得水凝胶进行了溶胀、粘弹性性质、形态学表征，以及细胞附着和增殖能力的研究。由肽二叠氮化物交联的水凝胶在叠氮基团之间具有较短间隔基时产生更高的储能模量（G'）。正如预期的那样，由于交联密度增加，随着前体浓度的增加，溶胀度降低而G'增加。将原代人皮肤成纤维细胞用作模型细胞，以探索使用RGD肽水凝胶进行基于细胞的伤口愈合的可能性。评估了细胞在水凝胶上的附着和增殖情况。与不含RGD肽的水凝胶相比，肽浓度为2.7 - 5.4 mM合成的RGD肽水凝胶实现了显著改善的细胞附着和更高的细胞增殖率。这些水凝胶可为组织修复的细胞递送提供一种平台技术。
