Stem cell growth on carbon-nanotube-based scaffolds

科学家们经常希望在试管中培养人体细胞，事实上，他们最终希望获得一种特殊类型的细胞，称为干细胞，并使它们在体外完全长成完整的器官。这些器官可以用来替代衰竭的器官，从而挽救生命。然而，这是非常困难的，其中一个原因是我们的细胞已经进化到在我们体内生长，细胞在体内并结合到一个复杂的基质上，这个基质不仅将它们保持在一起（从而防止我们的身体分解成一个大的细胞团），而且还为它们提供线索，例如，因此，如果我们想在试管中培养细胞，我们需要为细胞生长制造表面，模仿人体内粗糙、有弹性的表面。在这个提议中，我们希望获得在我们已经知道如何制造的表面上培养干细胞的技能。我们已经使用了一种独特的碳形式，称为碳纳米管，以制造与细胞内一些表面一样粗糙的表面。碳纳米管是一种长的碳管，直径只有十亿分之几米（人类的头发是1000多倍宽），但比这长得多，因此得名管。此外，科学家们已经证明，表面的粗糙度会影响细胞在其上的生长。因此，我们有细胞的表面，但缺乏培养细胞的特殊专业知识。我们将与加州的一群专门研究干细胞的科学家合作，并向他们学习。作为回报，他们将能够使用我们的纳米管支架来培养他们的细胞。我们将学习的新技能不会使我们能够生长完整的器官，但它们将使我们更好地了解生长中的干细胞如何与它们生长的表面相互作用，并提高我们生长这些细胞的能力。例如，当我们可以控制表面的粗糙度时，我们将能够看到是否存在细胞生长的最佳粗糙度，使得细胞在更光滑和更粗糙的表面上生长得更慢。

Scientists often wish to grow human cells in test-tubes, indeed ultimately they hope to take a special type of cell, called a stem cell, and cause them to grow into complete organs completely outside of the body. These organs could then be used to replace failed organs and so save lives. However, this is very difficult and one of the reasons for this is that our cells have evolved to grow inside our body where the cells are within and bind to a complex matrix which not only holds them together (and so prevents our body disintegrating into a large blob of cells) but also provides them with cues, e.g., grow here, don't grow there, become a nerve cell, etc. Thus, if we want to grow cells in test-tubes we need to produce surfaces for the cells to grow on that mimic the rough, elastic surfaces found within the body. In this proposal we want to acquire the skills to grow stem cells on surfaces that we already know how to make.We are already using a unique form of carbon, called carbon nanotubes to make surfaces that are as rough as some of the surfaces inside cells. Carbon nanotubes are long tubes of carbon that are only a few billionths of a metre across (a human hair is more than a 1000 times wider) but are much longer than this, hence the name tube. Also, scientists have shown that the roughness of surfaces affect how cells grow on them. Thus we have the surfaces for the cells but lack the special expertise in growing the cells. We will work with a group of scientists in California who specialise in stem cells, and learn from them. In return they will be able to use our nanotube scaffolds to grow their cells. The new skills we will learn will not enable us to grow complete organs, but they will allow us to both better understand how growing stem cells interact with the surface they are growing on, and to improve our ability to grow these cells. For example, as we can control the roughness of our surfaces we will able to see whether there is an optimal roughness for cell growth, such that the cells grow more slowly on both smoother and rougher surfaces.