Abstract In this work, a sensitive DNAzyme-based electrochemical sensor had been developed for Pb2+ detection with platinum nanoparticles decorated TiO2/α-Fe2O3 composite as signal labels. The morphological and compositional properties of the PtNPs/TiO2/α-Fe2O3 were examined by using transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The result showed that the shape of α-Fe2O3 nanocrystals were the cubic, the average length ranged from 150 to 300 nm, and the PtNPs with about 3–4 nm in diameter were well dispersed on the surface of TiO2/α-Fe2O3. TiO2/α-Fe2O3 were used as a “carrier” to load the PtNPs tracers as well as for Apt3 immobilization. In turn, the DNAzyme structure of Apt1 and Apt2 was immobilized on the gold electrode surface as the capture probes. Subsequently, DNAzyme modified electrodes reacted with target Pb2+ and the Apt3/PtNPs/TiO2/α-Fe2O3 composite were deposited on the electrode surface. The performance of the DNAzyme-based electrochemical sensor was tested by recording the electrocatalytic reduction current toward H2O2. Enhanced sensitivity was achieved by TiO2/α-Fe2O3 nanocomposites as a nanocarrier in order to PtNPs at a high ratio. The DNAzyme-based electrochemical sensor described here exhibited excellent sensitivity and specificity for target ion. This work represented a promising potential for on-site testing Pb2+ in real drinking water and serum sample analysis.

中文翻译：

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一种基于 DNAzyme 的灵敏电化学传感器，用于以铂纳米粒子装饰的 TiO2/α-Fe2O3 纳米复合材料作为信号标记检测 Pb2+

摘要 在这项工作中，以铂纳米粒子修饰的 TiO2/α-Fe2O3 复合材料作为信号标记，开发了一种基于 DNAzyme 的灵敏电化学传感器，用于 Pb2+ 检测。通过使用透射电子显微镜、X 射线衍射和 X 射线光电子能谱检查 PtNPs/TiO2/α-Fe2O3 的形态和组成特性。结果表明，α-Fe2O3纳米晶的形状为立方体，平均长度为150~300 nm，直径约3~4 nm的PtNPs很好地分散在TiO2/α-Fe2O3表面。TiO2/α-Fe2O3 被用作“载体”来加载 PtNPs 示踪剂以及固定 Apt3。反过来，Apt1 和 Apt2 的 DNAzyme 结构被固定在金电极表面作为捕获探针。随后，DNAzyme 修饰的电极与目标 Pb2+ 反应，Apt3/PtNPs/TiO2/α-Fe2O3 复合物沉积在电极表面。通过记录朝向 H2O2 的电催化还原电流来测试基于 DNAzyme 的电化学传感器的性能。TiO2/α-Fe2O3 纳米复合材料作为纳米载体实现了更高的灵敏度，以获得高比例的 PtNP。这里描述的基于 DNAzyme 的电化学传感器对目标离子表现出出色的灵敏度和特异性。这项工作代表了在实际饮用水和血清样品分析中现场检测 Pb2+ 的潜力。通过记录朝向 H2O2 的电催化还原电流来测试基于 DNAzyme 的电化学传感器的性能。TiO2/α-Fe2O3 纳米复合材料作为纳米载体实现了更高的灵敏度，以获得高比例的 PtNP。这里描述的基于 DNAzyme 的电化学传感器对目标离子表现出出色的灵敏度和特异性。这项工作代表了在实际饮用水和血清样品分析中现场检测 Pb2+ 的潜力。通过记录朝向 H2O2 的电催化还原电流来测试基于 DNAzyme 的电化学传感器的性能。TiO2/α-Fe2O3 纳米复合材料作为纳米载体实现了更高的灵敏度，以获得高比例的 PtNP。这里描述的基于 DNAzyme 的电化学传感器对目标离子表现出出色的灵敏度和特异性。这项工作代表了在实际饮用水和血清样品分析中现场检测 Pb2+ 的潜力。