Paegel Brian M, Grover William H, Skelley Alison M, Mathies Richard A, Joyce Gerald F
Department of Chemistry, Scripps Research Institute, La Jolla, California 92037, USA.
Anal Chem. 2006 Nov 1;78(21):7522-7. doi: 10.1021/ac0608265.
In vitro evolution of RNA molecules requires a method for executing many consecutive serial dilutions. To solve this problem, a microfluidic circuit has been fabricated in a three-layer glass-PDMS-glass device. The 400-nL serial dilution circuit contains five integrated membrane valves: three two-way valves arranged in a loop to drive cyclic mixing of the diluent and carryover, and two bus valves to control fluidic access to the circuit through input and output channels. By varying the valve placement in the circuit, carryover fractions from 0.04 to 0.2 were obtained. Each dilution process, which is composed of a diluent flush cycle followed by a mixing cycle, is carried out with no pipeting, and a sample volume of 400 nL is sufficient for conducting an arbitrary number of serial dilutions. Mixing is precisely controlled by changing the cyclic pumping rate, with a minimum mixing time of 22 s. This microfluidic circuit is generally applicable for integrating automated serial dilution and sample preparation in almost any microfluidic architecture.
RNA分子的体外进化需要一种执行多次连续系列稀释的方法。为了解决这个问题，已在三层玻璃-PDMS-玻璃装置中制造了一种微流体回路。400 nL的系列稀释回路包含五个集成膜阀：三个双向阀成环排列，以驱动稀释剂的循环混合和残留，还有两个总线阀，用于通过输入和输出通道控制流体进入回路。通过改变回路中的阀位置，可获得0.04至0.2的残留分数。每个稀释过程由一个稀释剂冲洗循环后跟一个混合循环组成，无需移液操作即可进行，400 nL的样品体积足以进行任意次数的系列稀释。通过改变循环泵送速率精确控制混合，最短混合时间为22秒。这种微流体回路通常适用于几乎任何微流体结构中集成自动化系列稀释和样品制备。
