Fine temporal control of the medium gas content and acidity and on-chip generation of series of oxygen concentrations for cell cultures
Fine temporal control of the medium gas content and acidity and on-chip generation of series of oxygen concentrations for cell cultures
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DOI：
10.1039/b816191g
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发表时间：
2009-01-01
期刊：
影响因子：
6.1
通讯作者：
Groisman, Alex
中科院分区：
文献类型：
--
作者：
Polinkovsky, Mark;Gutierrez, Edgar;Groisman, Alex
我们描述了两个微流控设备的设计、操作和应用，它们通过芯片上的气体混合产生一系列浓度为[O-2]的氧气。这两种装置都是由聚二甲基硅氧烷(PDMS)制成，并有两层通道，流动层和气体层。通过用氧敏感荧光染料对[O-2]的原位测量，我们发现通过PDMS的气体扩散导致流动层中水溶液中的[O-2]与注入到气层中的气体中的[O-2]在大约1秒的时间尺度上达到平衡。向气体层中注入二氧化碳会导致流动层中的pH值在大约0.5秒内下降。这两个设备的气体混合通道网络从输入到入口的两种气体中产生9种不同[O-2]的混合气体，从而在流动层中产生9种不同[O-2]的区域。第一种装置产生[O-2]在0-100%之间线性变化的氮氧混合物。第二种装置产生氮气-空气混合物，[O-2]在0到20.9%之间呈指数变化。该装置的流层设计用于在半渗透微室中培养细菌，第二个装置用于在一次实验中测量9个不同[O-2]条件下的大肠杆菌菌落生长曲线。在[O-2]为0、0.2和0.5%时的细胞分裂率有显著差异，进一步验证了该装置以高精度和高分辨率在流动层中设置[O-2]的能力。在传统的大规模培养中，设备中实现的[O-2]的控制程度和与呼吸引起的氧气消耗相关的稳健性将很难与之匹敌。所提出的装置和技术可用于微氧条件下的细菌和酵母的研究以及低氧条件下的哺乳动物细胞的研究。
We describe the design, operation, and applications of two microfluidic devices that generate series of concentrations of oxygen, [O-2], by on-chip gas mixing. Both devices are made of polydimethylsiloxane (PDMS) and have two layers of channels, the flow layer and the gas layer. By using in-situ measurements of [O-2] with an oxygen-sensitive fluorescent dye, we show that gas diffusion through PDMS leads to equilibration of [O-2] in an aqueous solution in the flow layer with [O-2] in a gas injected into the gas layer on a time scale of similar to 1 sec. Injection of carbon dioxide into the gas layer causes the pH in the flow layer to drop within similar to 0.5 sec. Gas-mixing channel networks of both devices generate series of 9 gas mixtures with different [O-2] from two gases fed to the inlets, thus creating regions with 9 different [O-2] in the flow layer. The first device generates nitrogen-oxygen mixtures with [O-2] varying linearly between 0 and 100%. The second device generates nitrogen-air mixtures with [O-2] varying exponentially between 0 and 20.9%. The flow layers of the devices are designed for culturing bacteria in semi-permeable microchambers, and the second device is used to measure growth curves of E. coli colonies at 9 different [O-2] in a single experiment. The cell division rates at [O-2] of 0, 0.2, and 0.5% are found to be significantly different, further validating the capacity of the device to set [O-2] in the flow layer with high precision and resolution. The degree of control of [O-2] achieved in the devices and the robustness with respect to oxygen consumption due to respiration would be difficult to match in a traditional large-scale culture. The proposed devices and technology can be used in research on bacteria and yeast under microaerobic conditions and on mammalian cells under hypoxia.