以修饰有荧光基团(FAM)的多巴胺核酸适体作为识别元件, 氧化石墨烯为猝灭剂, 构建了光学适体传感器用于检测多巴胺。通过π-π堆积作用力, 氧化石墨烯以共振方式把核酸适体上FAM能量转移到其表面, 荧光信号消失; 加入多巴胺后荧光恢复, 荧光强度恢复的大小与多巴胺浓度呈正相关关系。实验优化结果表明, 在反应时间5 min和10 μg/mL氧化石墨烯条件下, 氧化石墨烯可以达到对FAM的最高猝灭效率; 25 min孵育后, 多巴胺恢复荧光强度达到稳定; 传感器线性检测范围为1～500 μmol/L, 检测限达到1 μmol/L。所制备传感器具有检测范围宽、检测速度快、特异性强以及检测成本低等优点。

A fluorescent aptamer biosensor was constructed for the determination of dopamine. The dopamine aptamer modified 6-carboxyfluorescein (FAM) was used as the recognition element, and graphene oxide was the quencher. Through π-π stacking interaction, FAM energy can be transferred to the surface of the graphene oxide in resonant manner, and the fluorescence disappears. In the presence of DA, the fluorescence can be recovered and the fluorescence intensity is found to be in proportion to the concentration of DA. The optimized research results show that 10 μg/mL graphene oxide may achieve maximum quenching efficiency within 5 min reaction time. The fluorescence intensity can reach a stable recovery after 25 min incubation. The response to dopamine proves to be linear with the correlation coefficient up to 0.988 in the relevant concentration range of 1－500 μmol/L, and the detection limit is 1 μmol/L. The biosensor is characterized by its wide range of measurement, fast detection, low cost and so on.