| With the features of efficientcy, convience and micro-detection, biochip which is widely used in the fields of biological sciences, medical and medicine research, environmental monitoring and biochemical experiment is a new technology and develops rapidly in recent decades.Traditional fluorescence detection system utilizes photomultiplier tubes(PMT).to build up a complete image by dual axis scanning, but it has the drawbacks of limited imaging speed and high cost. Despite the system with cooled type area image detector improves the image speed and has stable sensitivity, it’s still expensive.Compared to the dual axis scanning, the line scanning fluorescence detection system offers a fundamentally simpler solution with one dimension scanning, which significantly simplifies the instrumentation. Besides, with the built-in thermoelectric cooler, it allows a long exposure time achieving a high performance even at low light levels. A LED is used as the light sources in the system instead of laser, which reduce the system size as well as power consumption.The system designs including the optical structure, light sourse, photoelectric conversion device and readout circuit were introduced and the requirement and difficulty were discussed. In addition, a confocal fluorescence detection system which was applied in the biochip was developed.The experiments involving the noise of curcuit, the signal noise ratio, the quantification limit, the linear concentration and the image resolution were conducted. The results indicated that the lowest quantification limit of the system was 0.01umol/L and the linear concentration ranged from 0.1umol/L to 10umol/L. The experiments of image resolution showed that the highest resolution reached 8.77μm.In conclusion, the confocal fluorescence detection system we developed had good repeatability and stability. Furthermore, the quality of images met the need of biomedical fluorescence and research. |
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