Laser-induced fluorescence detection system for microfluidic chips based on an orthogonal optical arrangement
Laser-induced fluorescence detection system for microfluidic chips based on an orthogonal optical arrangement
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DOI：
10.1021/ac060153q
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发表时间：
2006-06-01
影响因子：
7.4
通讯作者：
Fang, Zhao-Lun
中科院分区：
文献类型：
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作者：
Fu, Jing-Lin;Fang, Qun;Fang, Zhao-Lun
在这项工作中，一个简单的激光诱导荧光检测系统的基础上的正交光学安排的微流控芯片。通过检测微通道中通过芯片侧壁发射的荧光以减少来自激光源的散射光干扰来实现高灵敏度检测。一个特殊的交叉通道的配置，与1.5毫米的距离从分离通道的玻璃芯片的侧壁，设计，以促进收集发射的荧光通过侧壁。在这项研究中观察到的芯片平面上的散射激光的强度分布的显着差异被充分利用，以优化检测信号的S/N比通过拒绝散射光，无论是通过系统的测量和采用光线跟踪模拟。在芯片平面中45度的荧光收集角给出了最好的结果，散射光强度是在90度角处获得的散射光强度的1/38。荧光素钠和异硫氰酸荧光素标记的氨基酸被用作模型样品，以证明LIF系统的性能。获得了1.1 pM荧光素的检测限（S/N = 3），这是可比的优化共聚焦LIF系统芯片为基础的毛细管电泳。该系统除了具有较高的探测功率外，还具有光学结构简单、体积小、易于搭建等优点。
In this work, a simple LIF detection system based on an orthogonal optical arrangement for microfluidic chips was developed. Highly sensitive detection was achieved by detecting the fluorescence light emitted in the microchannel through the sidewall of the chip to reduce scattered light interference from the laser source. A special crossed-channel configuration, with a 1.5-mm distance from the separation channel to the sidewall of the glass chip, was designed in order to facilitate collection of emitted fluorescence light through the sidewall. The significant difference in intensity distribution of scattered laser light on the chip plane observed in this study was fully exploited to optimize S/N ratio of detected signals by rejection of scattered light, both through systematic measurements and employing ray-tracing simulation. A fluorescence collection angle of 45 degrees in the chip plane gave the best result, with a scattered light intensity 1/38 of that obtained at an angle of 90 degrees. Sodium fluorescein and fluorescein isothiocyanate-labeled amino acids were used as model samples to demonstrate the performance of the LIF system. A detection limit (S/N = 3) of 1.1 pM fluorescein was obtained, which is comparable to that of optimized confocal LIF systems for chip-based capillary electrophoresis. Apart from the high detection power, the system also has the advantages of simple optical structure, compactness, and ease in building.