The authors describe an electrochemical method for aptamer-based determination of insulin at femtomolar concentrations. The surface of a screen printed electrode was modified with ordered mesoporous carbon that was chemically modified with 1,3,6,8-pyrenetetrasulfonate (TPS). The amino-terminated aptamer was then covalently linked to TPS via reactive sulfonyl chloride groups. Subsequently, the redox probe Methylene Blue (MB) was interacted into the aptamer. The MB-modified binds to insulin and this results in the release of MB and a decreased signal as obtained by differential pulse voltammetry, best at a working voltage of −0.3 V (versus silver pseudo-reference electrode). Insulin can be quantified by this method in the 1.0 fM to 10.0 pM concentration range, with a 0.18 fM limit of detection (at 3σ/slope). The assay was applied to the determination of insulin in spiked human serum samples. The method is highly sensitive, selective, stable, and has a wide analytical range.Graphical abstractThe surface of a screen printed electrode was modified with ordered mesoporous carbon-1,3,6,8-pyrenetetrasulfonate. The amino-terminated aptamer was then linked to the 1,3,6,8-pyrenetetrasulfonate. Then, the Methylene Blue was interacted into the aptamer. The modified electrode was applied to the determination of insulin.

中文翻译：

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使用介孔碳和 1,3,6,8-芘四磺酸盐修饰的丝网印刷电极，基于电化学适体测定飞摩尔级胰岛素

作者描述了一种基于适配体测定飞摩尔浓度胰岛素的电化学方法。丝网印刷电极的表面用有序介孔碳改性，该碳用 1,3,6,8-芘四磺酸盐 (TPS) 进行化学改性。然后将氨基封端的适体通过反应性磺酰氯基团与 TPS 共价连接。随后，氧化还原探针亚甲蓝 (MB) 与适体相互作用。MB 修饰物与胰岛素结合，这导致 MB 的释放和通过差分脉冲伏安法获得的信号降低，最佳工作电压为 -0.3 V（相对于银伪参考电极）。通过这种方法可以在 1.0 fM 到 10.0 pM 的浓度范围内量化胰岛素，检测限为 0.18 fM（3σ/斜率）。该测定法用于测定加标人血清样品中的胰岛素。该方法灵敏度高、选择性好、稳定性好、分析范围广。图文摘要用有序介孔碳-1,3,6,8-芘四磺酸盐修饰丝网印刷电极表面。然后将氨基封端的适体连接到 1,3,6,8-芘四磺酸盐。然后，亚甲蓝与适体相互作用。修饰电极应用于胰岛素的测定。亚甲蓝与适体相互作用。修饰电极应用于胰岛素的测定。亚甲蓝与适体相互作用。修饰电极应用于胰岛素的测定。