构建了用于微流控细胞分析芯片的发光二极管(LED)诱导透射式荧光检测微系统，以克服现有荧光检测系统体积大、能耗高，以及激发光光路、检测区域和荧光收集光路间光学耦合效率低等问题。该系统的激发光光路和荧光收集光路互成135°，LED发出的激发光经透镜聚焦和激发光滤色片滤光后，经直径为200 μm的小孔光阑限束，然后投射到微流控芯片通道末端的检测区域；产生的荧光及杂散光经加工后置于微流控芯片底部的发射光高通干涉滤色薄膜后，被光电倍增管收集。以HepG2肝癌细胞为测试样本对该荧光检测微系统的有效性进行了评测，结果显示：当LED工作电流为200 mA，PMT控制电压为3.5 V时，可产生与背景噪声明显区分的峰值信号；用250 s观测时间得到了8个平均峰高为0.7 V的峰值信号，与荧光显微镜观察结果一致，实现了细胞的在线计数检测功能。提出的系统为新型微全细胞分析提供了一种新的技术途径。

A transmitted fluorescence detector induced by a Light Emitting Diode(LED) was established for integrating in a microfluidic cell chip.The detector overcomes the problems of system bulky in larger size,higher energy consumption and low coupling efficiency for inducing optical path, detection zone and fluorescence optical path. The angle for induced fluorescence optical path was designed to be 135°. The exciting light produced by the LED passed through an optical lens, an exciting light filter and a diaphragm aperture with a diameter of 200 μm, and then reached the detection zone of microfluidic chip. The induced fluorescence light and stray light passed through emitting high pass interference thin film filter fabricated at the back of the microfluidic chip, and finally was collected by a photomultiplier(PMT). The performance of the fluorescence detection micro system was verified by using HepG2 hepatoma carcinoma cells as samples. The experimental results show when the working current for LED and the control voltage for PMT are respectively set to be 200 mA and 3.5 V, the output is a peak signal which is obviously distinguished from background noise. 8 peak signals with an average value of 0.7 V are obtained within 250 s, which agrees with that from a fluorescence microscope. It shows the detection system realizes the function of cell counting detection, and is a new technological approach to micro total cell analysis systems.