Microfluidic electrophoresis chip coupled to microdialysis for in vivo monitoring of amino acid neurotransmitters
Microfluidic electrophoresis chip coupled to microdialysis for in vivo monitoring of amino acid neurotransmitters
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DOI：
10.1021/ac051044z
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发表时间：
2005-12-01
影响因子：
7.4
通讯作者：
Kennedy, RT
中科院分区：
文献类型：
--
作者：
Sandlin, ZD;Shou, MS;Kennedy, RT
采用微流控电泳仪对大鼠脑内初级胺类神经递质进行体外监测。该装置包含一个透析液的样品导入通道、一个用于邻苯二醛衍生化的柱前反应器、一个流动门控注射器和一个分离通道。使用共聚焦激光诱导荧光进行检测。体外实验结果表明，在370v /cm的电场作用下，该装置对氨基酸的检出限为200 nM，峰高相对标准偏差为2%，可在95 s内与30 200个理论板分离。第二个装置设计允许施加1320v /cm的电场，同时保持反应时间，允许在20秒内分离多达156000个理论板。通过在样品导入通道和电动网络交界处放置一个直径360 μ m的流体通道，该通道的流动阻力（0.15-7.2）× 10(8)倍于电动网络的流动阻力，可以忽略采样速率为0.3 ~ 1.2 μ L/min时，样品导入通道中流体动力流分裂到电动网络中的流动。通过连续注射，该设备允许透析液流以130-s的间隔进行分析。使用微透析/微流控装置记录麻醉大鼠在输注谷氨酸摄取抑制剂l -反式吡咯烷-2,4-二羧酸时纹状体中的谷氨酸浓度。这些结果证明了将微制造流体系统与采样探针耦合用于复杂介质（如哺乳动物大脑）化学监测的可行性。
Microfluidic electrophoresis devices were coupled on-fine to microdialysis for in vivo monitoring of primary amine neurotransmitters in rat brain. The devices contained a sample introduction channel for dialysate, a precolumn reactor for derivatization with o-phthaldialdehyde, a flow-gated injector, and a separation channel. Detection was performed using confocal laser-induced fluorescence. In vitro testing revealed that the initial device design had detection limits for amino acids of similar to 200 nM, relative standard deviation of peak heights of 2%, and separations within 95 s with up to 30 200 theoretical plates when applying an electric field of 370 V/cm. A second device design that allowed electric fields of 1320 V/cm to be applied while preserving the reaction time allowed separations within 20 s with up to 156 000 theoretical plates. Flow splitting into the electrokinetic network from hydrodynamic flow in the sample introduction channel was made negligible for sampling flow rates from 0.3 to 1.2 mu L/min by placing a 360-mu m-diameter fluidic access hole that had flow resistance (0.15-7.2) x 10(8)-fold lower than that of the electrokinetic network at the junction of the sample introduction channel and the electrokinetic network. Using serial injections, the device allowed the dialysate stream to be analyzed at 130-s intervals. In vivo monitoring was demonstrated by using the microdialysis/microfluidic device to record glutamate concentrations in the striatum of an anesthetized rat during infusion of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid. These results prove the feasibility of using a microfabricated fluidic system coupled to sampling probes for chemical monitoring of complex media such as mammalian brain.