As an essential biochemical indicator in the fields of pregnancy and oncology, human chorionic gonadotropin (HCG) can be evaluated using colloidal gold immunochromatographic paper and quantified using a biochemical analyzer based on the principle of the antibody sandwich method. In view of the inaccuracy of the former and the complication of the latter, this study constructed an accurate, sensitive and simple unlabeled biosensor based on peptide aptamer CGGGPPLRINRHILTR for HCG detection. Molecular Operating Environment (MOE) was used to simulate the aptamer and protein docking, and western blot (WB) was used to verify the binding effect and ratio. The peptide aptamer was characterized and was then reduced with tris-(2-carboxyethyl)-phosphine hydrochloride (TCEP). After electrochemical deposition of chloroauric acid on the screen-printed electrode (SPE), the aptamer was self-assembled on the electrode surface under optimal conditions. The active site of the electrode surface was blocked with 6-mercapto-1-hexanol (MCH) and BSA. The electrochemical impedance spectrum (EIS) was used to quantify HCG in the matrix. Showing a good linear relationship in the range of 5–1500 mIU mL⁻¹, with a detection limit of 1 mIU mL⁻¹, the biosensor remained stable at room temperature for 14 days. Because of its small size, stability, sensitivity and accuracy, this biosensor has great potential to become a portable diagnostic device for HCG.

中文翻译：

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基于肽适体的简单未标记人绒毛膜促性腺激素生物传感器

人绒毛膜促性腺激素（HCG）作为妊娠和肿瘤学领域必不可少的生化指标，可使用胶体金免疫层析纸进行评价，并基于抗体夹心法的原理使用生化分析仪进行定量。针对前者的不准确和后者的复杂性，本研究基于肽适配体CGGGPPLRINRHILTR构建了一种准确、灵敏、简单的未标记生物传感器，用于HCG检测。分子操作环境（MOE）用于模拟适配体和蛋白质对接，蛋白质印迹（WB）用于验证结合效果和比率。肽适体被表征，然后用三-(2-羧乙基)-膦盐酸盐(TCEP)还原。在丝网印刷电极（SPE）上电化学沉积氯金酸后，适体在最佳条件下自组装在电极表面。电极表面的活性位点被 6-mercapto-1-hexanol (MCH) 和 BSA 封闭。电化学阻抗谱 (EIS) 用于量化基质中的 HCG。在 5–1500 mIU mL 范围内显示出良好的线性关系^-1，检测限为1 mIU mL ^-1，生物传感器在室温下保持稳定14天。由于其体积小、稳定性、灵敏度和准确度高，这种生物传感器具有成为 HCG 便携式诊断设备的巨大潜力。