AbstractA method is described for photoelectrochemical determination of chloramphenicol (CLOA). It is based on the use of (a) aptamers protected with photoactive WS2 nanosheets, and (b) DNase I-assisted target recycling. The DNA aptamer without label was employed for recognition of CLOA. In the absence of CLOA, the aptamer is adsorbed on the surface of WS2. This leads to a decrease of photocurrent due to the steric-hindrance effect of aptamer DNA. The adsorption of WS2 also protects the aptamer from digestion by DNase. In the presence of CLOA, the aptamer will be desorbed from the WS2 surface due to formation of an aptamer/CLOA conjugate. This results in an increased photocurrent due to a decreased amount of aptamer DNA on the electrode surface. The increase of photocurrent can be further improved by applying DNase triggered catalytic recycling of CLOA. Under optimal experimental conditions, the response is linear 10 pM – 10 nM CLOA concentration range, with a 3.6 pM lower detection limit (at 3σ). This method is acceptably selective, accurate and stable. It was applied to the determination of CLOA in spiked milk samples and gave satisfactory results. Graphical abstractA simple and sensitive photoelectrochemical apta-biosensor was fabricated for chloramphenicol detection. In this work, WS2 nanosheets were employed as photoactive material, and DNase I catalytic chloramphenicol recycling strategy was adopted to amplify the detection signal.

中文翻译：

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基于二硫化钨 (WS2) 纳米片的氯霉素光电化学适配

摘要 介绍了一种光电化学测定氯霉素(CLOA)的方法。它基于使用 (a) 用光活性 WS2 纳米片保护的适体，和 (b) DNase I 辅助的目标回收。没有标记的DNA适体用于识别CLOA。在没有 CLOA 的情况下，适体吸附在 WS2 的表面。由于适体 DNA 的空间位阻效应，这会导致光电流降低。WS2 的吸附也保护适体不被 DNase 消化。在 CLOA 存在下，由于适体/CLOA 偶联物的形成，适体将从 WS2 表面解吸。由于电极表面上适体 DNA 的数量减少，这会导致光电流增加。通过应用DNase触发的CLOA催化回收可以进一步改善光电流的增加。在最佳实验条件下，响应在 10 pM – 10 nM CLOA 浓度范围内呈线性，检测下限为 3.6 pM（在 3σ 处）。该方法具有可接受的选择性、准确和稳定。应用于加标牛奶样品中CLOA的测定，结果令人满意。图形摘要制作了一种用于氯霉素检测的简单灵敏的光电化学适体生物传感器。在这项工作中，WS2 纳米片被用作光活性材料，并采用 DNase I 催化氯霉素回收策略来放大检测信号。该方法具有可接受的选择性、准确和稳定。应用于加标牛奶样品中CLOA的测定，结果令人满意。图形摘要制作了一种用于氯霉素检测的简单灵敏的光电化学适体生物传感器。在这项工作中，WS2 纳米片被用作光活性材料，并采用 DNase I 催化氯霉素回收策略来放大检测信号。该方法具有可接受的选择性、准确和稳定。应用于加标牛奶样品中CLOA的测定，结果令人满意。图形摘要制作了一种用于氯霉素检测的简单灵敏的光电化学适体生物传感器。在这项工作中，WS2 纳米片被用作光活性材料，并采用 DNase I 催化氯霉素回收策略来放大检测信号。