基于CdS纳米颗粒和HRP-AuNPs-apt的卡那霉素电化学发光适配体传感器研究

Electrochemiluminescence aptamer sensor for Kana base on CdS nanospheres and HRP-AuNPs-apt

为了建立高灵敏度检测卡那霉素(Kana)的方法,本论文用一步水热法制备了具有优良电化学发光(ECL)性能的花瓣状硫化镉纳米颗粒,在玻碳电极(GCE)表面修饰硫化镉纳米颗粒和金纳米粒子(AuNPs)。以辣根过氧化物-金纳米粒子-适配体复合物(HRP-AuNPs-apt)作为信号探针分子放大电化学发光信号。卡那霉素适配体的互补链(cDNA)通过金硫键连接到修饰在电极表面的AuNPs上,通过cDNA与复合物中Kana适配体的杂交反应制备ECL适配体传感器HRP-AuNPs-apt/cDNA/AuNPs/CdS/CS/GCE。过氧化氢作为ECL共反应剂,在HRP的催化作用下而被消耗,致使ECL信号减小。采用直接竞争模式,反应完成后,空白溶液中的ECL强度I_0与Kana溶液ECL强度I_p的差值ΔI(=I_p-I_0)作为ECL信号,ΔI随着Kana浓度的增大而增大。ΔI与游离的Kana浓度的对数在0.001到100μg·L^(-1)Kana浓度范围内呈良好的线性关系,检测限为0.5 ng·L^(-1)。该ECL适配体传感器对Kana的检测具有较高灵敏性和选择性。^(-1)

In order to establish a method for the detection of kanamycin( Kana) with high sensitivity,in this article,we reported that petaloid Cd S nanospheres which were prepared through a simple one-step hydrothermal method were used as electrochemiluminescence( ECL) emitter.A new conjugate was prepared with Kana aptamer( apt),Au nanoparticles( AuNPs) and horseradish peroxidase( HRP) as a biocatalyst for signal amplification.Cd S nanospheres and AuNPs adhered to GCE and denoted as AuNPs/Cd S/CS/GCE.After the Kana aptamer in the conjugates immobilized on the modified electrode though Au-thiol interactions hybridized with a its complementary DNA chain( c DNA),HRP in the conjugates catalyzed the redox reaction of hydrogen peroxide to cause ECL signal decreasing due to H_2O_2 as a majorcoreactant in the ECL emitter of Cd S nanospheres.When background ECL intensity stabilized,the ECL response was recorded as I_0. The recognition reaction between aptamer and Kana was performed,and the ECL response was recorded as I_p. The change in ECL intensity was given by ΔI = I_p-I_0. The difference value of ECL intensity( ΔI) increased linearly with the logarithm of Kana concentration,which can be used as the determination of Kana. Under the optimal conditions,the ECL signal was highly linearly increased with Kana concentrations over the range of 0. 001 to 100 μg·L^(-1),with a detection limit of 0. 5ng·L^(-1).This aptamer sensor was applied in the determination of Kana with high sensitivity and selectivity.