Department of Biomedical Engineering, University of Michigan, Ann Arbor, 48109, USA.
Lab Chip. 2010 Nov 7;10(21):2959-64. doi: 10.1039/c0lc00086h. Epub 2010 Sep 9.
Generation of stable soluble-factor gradients in microfluidic devices enables studies of various cellular events such as chemotaxis and differentiation. However, many gradient devices directly expose cells to constant fluid flow and that can induce undesired responses from cells due to shear stress and/or wash out of cell-secreted molecules. Although there have been devices with flow-free gradients, they typically generate only a single condition and/or have a decaying gradient profile that does not accommodate long-term experiments. Here we describe a microdevice that generates several chemical gradient conditions on a single platform in flow-free microchambers which facilitates steady-state gradient profiles. The device contains embedded normally-closed valves that enable fast and uniform seeding of cells to all microchambers simultaneously. A network of microchannels distributes desired solutions from easy-access open reservoirs to a single output port, enabling a simple setup for inducing flow in the device. Embedded porous filters, sandwiched between the microchannel networks and cell microchambers, enable diffusion of biomolecules but inhibit any bulk flow over the cells.
在微流控设备中生成稳定的可溶性因子梯度可使研究各种细胞事件，如趋化性和分化。然而，许多梯度设备直接使细胞暴露于恒定的流体流动中，这可能由于剪切应力和/或细胞分泌分子的洗脱而引起细胞的不期望反应。尽管已经有了无流动梯度的设备，但它们通常只能产生单一条件和/或具有衰减的梯度分布，不适应长期实验。在这里，我们描述了一种微设备，该设备在无流动微腔中在单个平台上生成几个化学梯度条件，从而促进稳定的梯度分布。该设备包含嵌入式常闭阀，可快速且均匀地将细胞同时播种到所有微腔室中。微通道网络将所需溶液从易于接近的开放式储液器分配到单个输出端口，为在设备中产生流动提供了简单的设置。嵌入的多孔过滤器夹在微通道网络和细胞微腔室之间，允许生物分子扩散，但抑制了细胞上的任何体流动。
