Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
Lab Chip. 2011 Sep 21;11(18):3057-63. doi: 10.1039/c1lc20311h. Epub 2011 Aug 1.
Controlled chemical delivery in microfluidic cell culture devices often relies on slowly evolving diffusive gradients, as the spatial and temporal control provided by fluid flow results in significant cell-perturbation. In this paper we introduce a microfluidic device architecture that allows for rapid spatial and temporal soluble signal delivery over large cell culture areas without fluid flow over the cells. In these devices the cell culture well is divided from a microfluidic channel located directly underneath the chamber by a nanoporous membrane. This configuration requires chemical signals in the microchannel to only diffuse through the thin membrane into large cell culture area, rather than diffuse in from the sides. The spatial chemical pattern within the microfluidic channel was rapidly transferred to the cell culture area with good fidelity through diffusion. The cellular temporal response to a step-function signal showed that dye reached the cell culture surface within 45 s, and achieved a static concentration in under 6 min. Chemical pulses of less than one minute were possible by temporally alternating the signal within the microfluidic channel, enabling rapid flow-free chemical microenvironment control for large cell culture areas.
在微流控细胞培养装置中进行受控化学物质传递通常依赖于缓慢演变的扩散梯度，因为流体流动提供的时空控制会导致显著的细胞干扰。在本文中，我们引入了一种微流控装置结构，允许在没有流过细胞的情况下，在大的细胞培养区域上快速进行时空可溶性信号传递。在这些设备中，细胞培养孔与位于腔室正下方的微流道通过纳米多孔膜隔开。这种配置要求微通道中的化学信号仅通过薄的膜扩散到大的细胞培养区域，而不是从侧面扩散。通过扩散，微流道内的空间化学图案可以快速、高保真地传递到细胞培养区域。细胞对阶跃信号的时间响应表明，染料在 45 秒内到达细胞培养表面，并在不到 6 分钟内达到静态浓度。通过在微流道内的信号进行时间交替，可以实现小于一分钟的化学脉冲，从而实现对大的细胞培养区域的快速无流动化学微环境控制。
