Chua Kian-Ngiap, Chai Chou, Lee Peng-Chou, Ramakrishna Seeram, Leong Kam W, Mao Hai-Quan
Division of Bioengineering, National University of Singapore Nanoscience and Nanotechnology Initiative, Singapore.
Exp Hematol. 2007 May;35(5):771-81. doi: 10.1016/j.exphem.2007.02.002.
Nanofiber scaffolds with amino groups conjugated to fiber surface through different spacers (ethylene, butylenes, and hexylene groups, respectively) were prepared and the effect of spacer length on adhesion and expansion of umbilical cord blood hematopoietic stem/ progenitor cells (HSPCs) was investigated.
Electrospun polymer nanofiber scaffolds were functionalized with poly(acrylic acid) grafting, followed by conjugation of amino groups with different spacers. HSPCs were expanded on aminated scaffolds for 10 days. Cell proliferation, surface marker expression, clonogenic potential, and nonobese diabetic (NOD)/severe combined immunodeficient (SCID) repopulation potential of the expanded cells were evaluated following expansion culture.
Aminated nanofiber scaffolds with ethylene and butylene spacers showed high-expansion efficiencies (773- and 805-fold expansion of total cells, 200- and 235-fold expansion of CD34+CD45' cells, respectively). HSPC proliferation on aminated scaffold with hexylene spacer was significantly lower (210-fold expansion of total cells and 86-fold expansion of CD34+CD45+ cells), but maintained the highest CD34+CD45+ cell fraction (41.1%). Colony-forming unit granulocyte-erythrocyte-monocyte-megakaryocyte and long-term culture-initiating cell maintenance was similar for HSPCs expanded on all three aminated nanofiber scaffolds; nevertheless, the NOD/SCID mice engraftment potential of HSPCs expanded on aminoethyl and aminobutyl conjugated nanofibers was significantly higher than that on aminohexyl conjugated nanofibers.
This study demonstrated that aminated nanofibers are superior substrates for ex vivo HSPC expansion, which was correlated with the enhanced HSPC adhesion to these aminated nanofibers. The spacer, through which amino groups were conjugated to nanofiber surface, affected the expansion outcome. Our results highlighted the importance of scaffold topography and cell-substrate interaction to regulating HSPC proliferation and self-renewal in cytokine-supplemented expansion.
制备了通过不同间隔基团（分别为乙烯基、丁烯基和己烯基）与纤维表面共轭连接氨基的纳米纤维支架，并研究间隔基团长度对脐带血造血干细胞/祖细胞（HSPCs）黏附及增殖的影响。
通过聚丙烯酸接枝对静电纺丝聚合物纳米纤维支架进行功能化处理，随后连接带有不同间隔基团的氨基。HSPCs在胺化支架上培养10天。在扩增培养后，对扩增细胞的增殖、表面标志物表达、集落形成能力以及非肥胖糖尿病（NOD）/重症联合免疫缺陷（SCID）小鼠体内的再增殖能力进行评估。
带有乙烯基和丁烯基间隔基团的胺化纳米纤维支架显示出较高的扩增效率（总细胞分别扩增773倍和805倍，CD34+CD45+细胞分别扩增200倍和235倍）。带有己烯基间隔基团的胺化支架上HSPCs的增殖显著较低（总细胞扩增210倍，CD34+CD45+细胞扩增86倍），但维持了最高的CD34+CD45+细胞比例（41.1%）。在所有三种胺化纳米纤维支架上扩增的HSPCs，其粒-红-单核-巨核系集落形成单位和长期培养起始细胞维持情况相似；然而，在氨基乙基和氨基丁基共轭纳米纤维上扩增的HSPCs在NOD/SCID小鼠体内的植入能力显著高于在氨基己基共轭纳米纤维上扩增的HSPCs。
本研究表明，胺化纳米纤维是体外HSPCs扩增的优质底物，这与HSPCs对这些胺化纳米纤维的黏附增强相关。氨基与纳米纤维表面共轭连接所通过的间隔基团影响扩增结果。我们的结果突出了支架拓扑结构和细胞-底物相互作用在细胞因子补充扩增中调节HSPCs增殖和自我更新的重要性。
