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MIT creates 3-D scaffold for growing stem cells
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MIT creates 3-D scaffold for growing stem cells CAMBRIDGE, Mass. Stem cells grew, multiplied and differentiated into brain cells on a new three-dimensional scaffold of tiny protein fragments designed to be more like a living body than any other cell culture system. An MIT engineer and Italian colleagues will report the invention-which may one day replace the ubiquitous Petri dish for growing cells-in the Dec. 27th issue of the PLoS ONE. Shuguang Zhang, associate director of MIT's Center for Biomedical Engineering, is a pioneer in coaxing tiny fragments of amino acids called self-assembling peptides to organize themselves into useful structures. Working with visiting graduate student Fabrizio Gelain from Milan, Zhang created a designer scaffold from a network of protein nanofibers, each 5,000 times thinner than a human hair and containing pores up to 20,000 times smaller than the eye of a needle. The researchers were able to grow a healthy colony of adult mouse stem cells on the three-dimensional scaffold without the drawbacks of two-dimensional systems. In addition to helping researchers get a more accurate picture of how cells grow and behave in the body, the new synthetic structure can provide a more conducive microenvironment for tissue cell cultures and tissues used in regenerative medicine, such as skin grafts or neurons to replace brain cells lost to injury or disease. The scaffold itself can be transplanted directly into the body with no ill effects. "The time has come to move on from two-dimensional dishes to culture systems that better represent the natural context of cells in tissues and organs" said Zhang, whose coauthors on the paper, in addition to Gelain, are from institutes and medical schools in Milan, Italy. Life in two dimensions Biomedical researchers have become increasingly aware of the limitations of growing living cells in coated, two-dimensional Petri dishes and glass slides. In the body, cells are attached to and supported by the cells, other structures and proteins around them. A cell's normal environment is a complex network of tiny fibers, gaps and pores through which oxygen, hormones and nutrients are delivered and waste products filtered away. Cells move within their natural environments in response to chemical signals or other stimuli. Researchers are aware that cells on flat surfaces have skewed metabolisms, gene expression and growing patterns. But the only choices have been glass labware and a product called Matrigel, a gelatinous protein mixture secreted by mouse tumor cells. While Matrigel does resemble a complex extracellular environment, it also contains growth factors and unknown proteins that limit its desirability for experiments requiring precise conditions "Synthetic biopolymer microfiber scaffolds have been studied for more than 30 years to mimic a living 3D microenvironment, but concerns exist about their degradation products and chemicals" the authors wrote in the paper. Other synthetic polymer biomaterials are simply too big. Getting cells to grow on them is like forcing spiders to build webs on skyscraper girders. Zhang's nanofiber scaffold, around 1,000 times smaller than the existing systems, is much closer in size to the extracellular matrices that living cells manufacture themselves. Adding motifs With the addition of defined amino acid fragments called active motifs, the scaffold can be fashioned to coax stem cells to behave in certain desirable ways-such as differentiating into needed body tissues or migrating toward bone marrow and other natural destinations. "What makes these designer scaffolds particularly interesting is that cells survive longer and differentiate better without additional soluble growth factors," Zhang said. "This suggests that extracellular microenvironments may play a more important role for cell survival and for carrying out cell functions than previously thought." The active motif method could be readily adapted to studying cell-to-cell interaction, cell migrations, tumor and cancer cell interaction with normal cells, cell-based drug testing and other diverse applications. "I believe that in the next 20 years all cell cultures will be in 3D with the designer scaffolds, and most textbooks about cell biology will have to be revised when people obtain results from 3D cell culture studies" Zhang said. The researchers are now testing the designer scaffold with a variety of cells, including tooth, bone, heart, liver, cartilage, skin, pancreas, blood cells and artery-forming cells. Disclaimer The following press release refers to an upcoming article in PLoS ONE. It has been contributed by the article authors and/or their institutions. The opinions expressed do not necessarily reflect the views of the staff or the editors of PLoS ONE. This work was supported by Olympus Corp. and the National Institutes of Health. Citation: Gelain F, Bottai D, Vescovi A, Zhang S (2006) Designer Self-Assembling Peptide Nanofiber Scaffolds for Adult Mouse Neural Stem Cell 3-Dimensional Cultures. PLoS ONE 1(1): e119. doi:10.1371/journal.pone.0000119 PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.doi.org/10.1371/journal.pone.0000119 PRESS ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/pone-01-01-zhang.pdf [ Last edited by luo.henry on 2008-4-11 at 13:28 ] |
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麻省理工学院创造出3D支架供干细胞增长 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~搞组织工程的XDJM有何想法呢？~~ 信息来源：华文生技网 麻省理工和意大利的研究人员于12月27日的PloS ONE中发表研究结果，这种支架将有可能取代广泛用于培养细胞的培养基。这项研究的负责人是MIT的华裔科学家Shuguang Zhang。他利用一种蛋白质奈米纤维网络设计出一种支架。这种奈米蛋白纤维要比一根人头发细5000倍，并且含有比针眼小2000倍的孔。 研究人员能够在3D支架上培养一种健康的成体小鼠干细胞，并且没有平面培养系统的缺点。这种新的合成结构除了能够帮助研究人员获得更精确的体内细胞生长和行为的影像之外，还能够提供组织细胞培养和再生组织更有益的微小环境。 直接将这种支架移植到身体中，并不会造成任何副作用。目前的技术发展趋势就是从2D的培养皿进化到可以代表组织和器官中自然细胞的培养系统。 体内细胞的正常环境是一个复杂的微小纤维、缺口和孔洞构成的网络。在这些缺口和孔洞中，氧气、激素和营养物质可以运输传递，且废物可以过滤送走。细胞在天然环境中能够对化学信号或其它刺激产生反应而移动。研究人员发现，在覆盖了培养基的平片培养皿和玻璃片中，培养活细胞存在着许多的限制。 平面上的细胞培养会造成不对称的代谢、基因表达和生长模式，这些无法满足需要精确条件限定的实验的需求。在添加了特定的活性motifs的胺基酸片段后，这种支架可以引诱干细胞以特定的方式来分化成身体组织所需的细胞类型。这种新的培养支架可以用于研究细胞间交互作用、细胞迁移、肿瘤和癌细胞与正常细胞之间的交互作用，以及用于以细胞为基础的药物检测等应用。 （编译/姜欣慧） (资料来源 : biocompare) |
2楼2007-01-16 21:56:17