【摘要】 本文合成了La³⁺掺杂的CdS量子点（CdS:La QDs）,以其作为发光材料。将量子点吸附于玻碳电极（GCE）表面。采用卡那霉素（Kana）的适配体（apt）及其互补链（cDNA）制备传感器，使apt与cDNA在电极表面杂交形成双链DNA（dsDNA）,然后用氯化血红素（hemin）溶液孵育该修饰电极，使hemin嵌入至dsDNA中，制得Kana电化学发光适配体传感器，记作hemin-dsDNA/CdS:La/GCE。建立了简便、灵敏的检测Kana的电化学发光（ECL）方法，当不存在Kana时，电极表面的hemin作为模拟过氧化物酶会催化溶液中的H₂O₂还原为OH^-,使作为量子点电化学发光共反应剂的H₂O₂在电极表面的浓度减小，从而减弱电极表面量子点的电化学发光强度。当存在Kana时，其会与适配体特异性结合形成复合物，导致部分dsDNA发生解旋，该复合物以及部分因dsDNA解旋而释放出的hemin分子从电极表面脱落，从而使量子点的电化学发光强度增加，基于此原理可以实现对Kana的特异性检测。以传感器在Kana溶液中的ECL强度（I）与传感器在空白溶液中的ECL强度（I₀）的差值ΔI（=I-I₀）作为响应信号，ΔI与Kana浓度的对数值在1.0×10^-11～1.0×10^-7 mol·L^-1浓度范围呈良好的线性关系，检出限为5×10^-12 mol·L^-1。该传感器具有较好的稳定性和选择性，可用于实际样品中卡那霉素的检测。更多还原

【Abstract】 In this article, La³⁺-doped CdS quantum dots（CdS:La QDs）were synthesized and were used as luminescent materials.Quantum dots were adsorbed on the surface of a glassy carbon electrode（GCE）.A sensor for kanamycin（Kana）was prepared by aptamer（apt）and its complementary strand（cDNA）.The aptamer hybridized with cDNA to form double-stranded DNA（dsDNA）.And then the modified electrode was incubated in hemin solution.Hemin was intercalated into dsDNA.A simple and sensitive electrochemiluminescence（ECL）method for detecting Kana was established.In the absence of Kana, hemin on the electrode surface, as a simulated peroxidase, will catalyze the reduction of H₂O₂ in solution to OH^-.The reaction will reduce the concentration of H₂O₂ on the electrode surface, thus weakening the electrochemiluminescence intensity of the quantum dots.In the presence of Kana, it will specifically bind with the aptamer, resulting in the unwinding of dsDNA.The complex formed by aptamer and Kana as well as some hemin molecules which were released due to the unwinding of dsDNA will fall off the electrode surface.Thus the electrochemiluminescence intensity of quantum dots will increased.Based on this principle, the specific detection of Kana can be realized.Using the difference ΔI（=I-I₀）between the ECL intensity（I）of the sensor in Kana solution and the ECL intensity（I₀）of the sensor in blank solution as response signal.ΔI versus the logarithm of Kana concentration showed a good linear relationship in the concentration range of 1.0×10^-11～1.0×10^-7 mol·L^-1 Kana, and the detection limit was 5×10^-12 mol·L^-1.The sensor has good stability and selectivity, and can be used for the detection of Kana in real samples.更多还原