A novel label-free fluorescence aptasensor was established for the detection of dopamine based on dopamine-triggered Exonuclease III- and SYBR Green I-assisted template DNA recycling and a decrease in fluorescence. SYBR Green I was selected as the fluorescent indicator; SYBR Green I fluoresces upon binding to double stranded DNA (dsDNA). The template DNA (tDNA) was designed to contain two regions: one complementary to the complementary strand (cDNA) and the other complementary to the aptamer. Various concentrations of dopamine automatically triggered the Exonuclease III restriction digestion to release SYBR Green I. Consequently, the fluorescence signal significantly decreased. Therefore, a method for detecting the dopamine concentration was established. Polyacrylamide gel electrophoresis was also used to confirm the feasibility of the developed sensor for detecting dopamine. Under optimal conditions, the variation in fluorescence was proportional to the concentration of dopamine in the range of 1.0 × 10^-10 M to 10.0 × 10^-9 M, with a detection limit of 8.0 × 10^-11 M. The developed aptasensor showed good selectivity and was successfully applied to detect dopamine in mouse brain tissues. Due to its remarkable sensitivity and selectivity, the constructed fluorescence aptasensor was applicable not only for the routine detection of dopamine but also for diagnosing disease.

建立了一种新型的无标记荧光适体传感器，用于基于多巴胺触发的核酸外切酶III和SYBR Green I辅助的模板DNA回收并检测荧光的降低来检测多巴胺。SYBR Green I被选为荧光指示剂；SYBR Green I与双链DNA（dsDNA）结合后发出荧光。模板DNA（tDNA）设计为包含两个区域：一个与互补链（cDNA）互补，另一个与适体互补。各种浓度的多巴胺会自动触发核酸外切酶III限制性酶切以释放SYBR GreenI。因此，荧光信号显着降低。因此，建立了一种检测多巴胺浓度的方法。聚丙烯酰胺凝胶电泳也被用于确认开发的用于检测多巴胺的传感器的可行性。在最佳条件下，荧光的变化与多巴胺的浓度成正比，范围为1.0×10^-10 M至10.0×10 ^-9 M，而为8.0×10的检测极限^-11 M的发达适体传感器表现出良好的选择性，并成功地应用于检测小鼠脑组织的多巴胺。由于其出色的灵敏度和选择性，所构建的荧光适体传感器不仅可用于多巴胺的常规检测，而且可用于疾病的诊断。