Design and implementation of ratiometric fluorescence detection system for serum bilirubin

现有胆红素定量检测方法存在成本高、灵敏度低的问题。由于血清胆红素水平与心血管疾病风险呈负相关，为实现对低水平胆红素的测定，本文运用层层自组装方法，将能发出蓝色荧光和红色荧光的金纳米簇探针沉积于同一薄膜中，对两种探针的荧光强度比值进行定量，构建比率型荧光传感器。在此传感器基础上，根据胆红素对薄膜传感器发生的荧光猝灭效应，设计了一种便携式的比率型血清胆红素荧光检测系统。系统硬件部分主要由主控芯片STM32F407、TSL237及TSL238T光频传感器组成。本系统通过三维打印设计了避光的检测暗室，减少环境光干扰。实验表明，所设计的比率型荧光检测系统具有较强的抗干扰性、稳定性和准确性。该系统检测胆红素的线性相关度为0.987，具有良好的线性关系，在重复性实验以及与标准仪器测试结果的对比中都具有较好的效果。本系统有望用于对低水平血清胆红素的测定。.; The current quantitative methods of bilirubin have disadvantages such as high cost and low sensitivity. Due to the negative correlation between the level of serum bilirubin and the risk of cardiovascular diseases, a fluorescent ratiometric film sensor was developed aiming at bilirubin detection at low level concentration. Blue-emitting and red-emitting gold nanoclusters were assembled into the same film using layer-by-layer self-assembly technology. Detection of bilirubin was achieved based on the intensity ratio of the two nanoclusters. Bilirubin exposure causes fluorescent quenching of the film. The fluorescence intensity ratio of the two cluster probes had quantitative relationship versus bilirubin concentration. Based on this film sensor, a portable fluorescence detection system was designed for the ratiometric sensing of bilirubin. The hardware of the system was mainly composed of main control chip STM32F407, TSL237 and TSL238T optical frequency sensor. A light-avoiding dark room and detection light path were designed through three-dimensional printing to reduce the interference from ambient light and improve detection accuracy. Experimental results showed that the proposed detection system had strong anti-interference, good stability and accuracy. The linear coefficient of bilirubin detected by this system was 0.987. The system presented good results in reproducible experiments and possessed a good linear relationship with the data obtained by standard spectrofluorometer. The portable system is expected to detect serum bilirubin at low levels.