基于目标物诱导置换及纳米金催化的新型荧光技术检测腺苷

在一定条件下, 磁性纳米颗粒上修饰的腺苷核酸适体与纳米金标记的核酸探针杂交; 再加入目标物腺苷诱导适体构象变换, 并置换出金标探针; 经磁场分离后, 游离的金标探针进一步用于催化抗坏血酸还原铜离子, 使铜离子对钙黄绿素的荧光猝灭得到抑制. 由于极少量的纳米金能够催化大量铜离子还原并沉积在其表面, 铜离子浓度急剧降低, 从而改变钙黄绿素的荧光信号. 实验结果表明, 腺苷的动力学响应浓度范围为100 pmol/L~10 nmol/L, 检出限低至80 pmol/L. 核酸适体的高度特异识别性能保证了该方法具有良好的选择性.

Novel Fluorescent Technique for Detecting Adenosine Based on DNA Strand Displacement Induced by Target-aptamer Complex and Metal Deposition Catalyzed by Gold Nanoparticles

Using adenosine as model analyte,a novel homogeneous fluorescent method with high sensitivity and specificity was proposed.It involves two kinds of DNA probe conjugated nanoparticles-aptamer modified magnetic nanoparticles and capture DNA probe derivatized gold nanoparticles(GNPs),which were connected together via hybridization.The conformational transition of aptamer induced by adenosine-aptamer complex contributes to the displacement of probe conjugated GNP,which further catalyzes the reduction of Cu2+ by ascorbic acid,causing the deposition of Cu atom on the surface of GNP.The fluorescence quenching of calcein was restored as the consumption of Cu2+.The experimental results demonstrated that the dynamic range for adenosine detection was from 100 pmol/L to 10 nmol/L,with a detection limit of 80 pmol/L.The proposed method shows high selectivity for the specific recognition of adenosine by its aptamer.