AbstractAn aptamer based method is described for the electrochemical determination of ampicillin. It is based on the use of DNA aptamer, DNA functionalized gold nanoparticles (DNA-AuNPs), and single-stranded DNA binding protein (ssDNA-BP). When the aptamer hybridizes with the target DNA on the AuNPs, the ssDNA-BP is captured on the electrode surface via its specific interaction with ss-DNA. This results in a decreased electrochemical signal of the redox probe Fe(CN)63− which is measured best at a voltage of 0.188 mV (vs. reference electrode). In the presence of ampicillin, the formation of aptamer-ampicillin conjugate blocks the further immobilization of DNA-AuNPs and ssDNA-BP, and this leads to an increased response. The method has a linear reposne that convers the 1 pM to 5 nM ampicillin concentration range, with a 0.38 pM detection limit (at an S/N ratio of 3). The assay is selective, stable and reproducible. It was applied to the determination of ampicillin in spiked milk samples where it gave recoveries ranging from 95.5 to 105.5%. Graphical abstractSchematic of a simple and sensitive electrochemical apta-biosensor for ampicillin detection. It is based on the use of gold nanoparticles (AuNPs), DNA aptamer, DNA functionalized AuNPs (DNA-AuNPs), and single-strand DNA binding protein (SSBP).

中文翻译：

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使用单链 DNA 结合蛋白和 DNA 功能化金纳米粒子基于适配体伏安法测定氨苄青霉素

摘要描述了一种基于适配体的氨苄青霉素电化学测定方法。它基于 DNA 适体、DNA 功能化金纳米粒子 (DNA-AuNPs) 和单链 DNA 结合蛋白 (ssDNA-BP) 的使用。当适体与 AuNP 上的目标 DNA 杂交时，ssDNA-BP 通过其与 ss-DNA 的特异性相互作用被捕获在电极表面。这导致氧化还原探针 Fe(CN)63- 的电化学信号降低，在 0.188 mV（相对于参比电极）的电压下测量最佳。在氨苄青霉素存在下，适体-氨苄青霉素缀合物的形成阻止了 DNA-AuNPs 和 ssDNA-BP 的进一步固定，这导致反应增加。该方法具有线性响应，可将 1 pM 至 5 nM 氨苄青霉素浓度范围转换为 0。38 pM 检测限（信噪比为 3）。该测定具有选择性、稳定和可重复性。它用于测定加标牛奶样品中的氨苄青霉素，回收率为 95.5% 至 105.5%。用于氨苄青霉素检测的简单而灵敏的电化学适体生物传感器的图形摘要示意图。它基于金纳米粒子 (AuNPs)、DNA 适配体、DNA 功能化 AuNPs (DNA-AuNPs) 和单链 DNA 结合蛋白 (SSBP) 的使用。