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【bio-news】胚胎干细胞有益于Bumpy Nanoscale Mattres
12/13/06 -- Nothing in the cellular world is flat. Even the flattest of basement membranes has topography; bumps, if you like, beneath the cellular mattress.
Unlike the princess kept awake by the pea, human embryonic stem (HES) cells do better when cultured on a substrate deliberately printed with nanoscale grooves and ridges, according to researchers from the University of Wisconsin-Madison.
The researchers used soft lithography to stamp polyurethane substrates with a nano- micron scale topography; a rugged cellular landscape ranging from a few billionths to a few millionths of a meter in altitude.
The HES cells in culture seemed to appreciate the bumps. A line of HES cells grown for five days on the artificial ridges and grooves kept their "stemness," their self-renewing phenotype, far better than HES cells plated on standard flat culture surfaces, according to Daniel McFarlin, K.J. Finn, and Chris Murphy of the University of Wisconsin's School of Veterinary Medicine, who teamed with P.F. Nealey of the University's Department of Chemical Engineering.
Unlike stem cells derived from adult tissues, which have a limited number of cell doublings, embryonic stem cells cultured under the right conditions have the potential to divide indefinitely, without losing their pluripotent properties. But until now, HES cell cultures had a tendency to spontaneously differentiate, that is, to veer off without warning into a developmental pathway. HES cell cultures have to be closely watched to remove any of these spontaneously differentiated colonies.
Researchers have looked at surface chemistry, growth factors, and mechanical forces as factors in runaway stem cell differentiation, but topography is a new dimension for HES, say Murphy and McFarlin, and a highly promising one.
This is the first demonstration that the physical topography, using controlled feature dimensions, of cell culture surfaces influences HES cell differentiation and self-renewal, according to the researchers. For HES cells to realize their potential in clinical medicine, they would have to be cultured in great quantities and with great fidelity to their pluripotent phenotype. Fine-tuning their nano-micro topography could boost the efficiency of HES cell propagation.
Source: American Society for Cell Biology
http://www.bio.com/newsfeatures/newsfeatures_research.jhtml;jsessionid=OLHVXI3T1UEQLR3FQLMCFEWHUWBNSIV0?cid=24200029 Embryonic Stem Cells Do Better on Bumpy Nanoscale Mattress
纳米疙瘩铺凹凸床，胚干细胞安睡其上
12/13/06 -- Nothing in the cellular world is flat. Even the flattest of basement membranes has topography; bumps, if you like, beneath the cellular mattress. 编译：
纳米疙瘩铺凹凸床，胚干细胞安睡其上
12/13/06
在细胞的世界里，没有什么是平坦的，哪怕最平坦的基底膜也有高低起伏的表面。
豌豆公主会因为床垫下的一颗豆子而睡不着，相比起来，人胚干细胞（HES cells)要好的多。据Wisconsin-Mandison大学的研究人员，在有意布满纳米级“山壑”的培养基上，HES细胞生长的更好。
研究人员用软光刻技术在聚亚胺酯基质上刻出纳米级到微米级的微观地形，这些凹凸不平的蜂窝状地貌高度仅几十亿到几百万分之一米。
HES细胞似乎更青睐崎岖不平的表面。来自Wisconsin大学兽医学院和化学工程学院的Daniel McFarlin等研究者发现，在人造的凹凸培养基上，一株HES细胞生长了5天仍保持它的“干细胞本色”，即能自我更新的表型，而在标准平板培养基上生长的HES细胞远不能保持这么久。
从成人组织分离的干细胞的倍增次数是有限的，而胚胎干细胞则不同，在合适的条件下具有无限倍增而不丧失多向分化性的潜力。但目前为止，培养中的HES细胞有自发分化的倾向，也就是说，会出其不意地转向某条发育的岔道。因此，必须密切观察培养的HES细胞，并随时去掉自发分化的细胞集落。
Murphy 和 McFarlin 指出，研究者们已着着眼于研究表面化学、细胞因子和机械作用力等可能使干细胞进入分化歧途的因素，而基质的表面微观形貌则提供了一个前景广阔的新视角。
这是人们首次证明，通过改变细胞培养基表面的物理微观形貌并控制尺度，可以影响HES细胞的分化和自我更新。能大量培养HES细胞，并保证其具有多能分化表型，是HES细胞在临床医学中大展拳脚的前提。而对HES细胞生长基质表面形貌的精雕细琢，将大大增加其繁殖效率。
来源：美国细胞生物学学会 [标签:content1][标签:content2]
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作者:admin@医学,生命科学 2011-03-06 05:23
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