期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：20
页码：12542-12547
DOI：10.1073/pnas.192457199
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Little is known about the influence of substrate-bound gradients on neuronal development, since it has been difficult to fabricate gradients over the distances typically required for biological studies (a few hundred micrometers). This article demonstrates a generally applicable technique for the fabrication of substrate-bound gradients of proteins with complex shapes, using laminar flows in microchannels. Gradients that range from pure laminin to pure BSA were formed in solution by using a network of microchannels, and these proteins were allowed to adsorb onto a homogeneous layer of poly-L-lysine. Rat hippocampal neurons were cultivated on these substrate-bound gradients. Analysis of optical images of these neurons showed that axon specification is oriented in the direction of increasing surface density of laminin. Linear gradients in laminin adsorbed from a gradient in solution having a slope of {nabla}[laminin] > about 0.06 {micro}g (ml*{micro}m)-1 (defined by dividing the change of concentration of laminin in solution over the distance of the gradient) orient axon specification, whereas those with {nabla}[laminin] < about 0.06 {micro}g (ml*{micro}m)-1 have no effect.
