Zhou Yao, Lin Qiao
Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
Sens Actuators B Chem. 2014 Jan;190:334-341. doi: 10.1016/j.snb.2013.08.073. Epub 2013 Sep 3.
This paper presents a class of novel microfluidic concentration gradient generation (CGG) devices that create temporally stable chemical concentration gradients with complex shapes in a flow-free environment. The devices feature a two-layer channel design and the incorporation of a semipermeable membrane, which effectively segregates the concentration gradient region in the lower layer from the flow of reagent sample (simply "sample" onward) and buffer in the upper layer. In the mean time, free diffusion across the membrane constantly replenishes sample and buffer to maintain a stable concentration. The shapes of the concentration gradients are controlled by the geometries of the micro-channels and chambers. Concentration gradients with complex shapes can be achieved by piecewise combining constituent gradients with elementary shapes. Capable of generating concentration gradients in a flow-free environment, our devices eliminate undesirable flow stimulation on biological cells under investigation, while maintaining a stable chemical environment for cell studies.
本文介绍了一类新型的微流控浓度梯度生成（CGG）装置，该装置可在无流动环境中创建具有复杂形状的时间稳定化学浓度梯度。这些装置采用双层通道设计，并结合了半透膜，可有效将下层的浓度梯度区域与上层的试剂样品（以下简称“样品”）和缓冲液流隔离开来。同时，通过膜的自由扩散不断补充样品和缓冲液以维持稳定的浓度。浓度梯度的形状由微通道和腔室的几何形状控制。通过将具有基本形状的组成梯度进行分段组合，可实现具有复杂形状的浓度梯度。我们的装置能够在无流动环境中生成浓度梯度，消除了对所研究生物细胞的不良流动刺激，同时为细胞研究维持稳定的化学环境。
