Continuous monitoring of stress through detecting specific biochemical markers such as cortisol plays a crucial role in the early detection of various diseases. Electrochemical aptamer sensor involving binding induced conformational change allows the continuous measurement of biomarkers. A reagent-less aptamer-based biosensing platform that allows a continuous and real-time cortisol measurement is developed in this context. The aptamer is conjugated with methylene blue, which acts as a redox reporter to probe the cortisol binding quantitatively on the sensor surface. The cortisol specific aptamers were chemically modified with amine and thiol functional groups to facilitate redox reporter conjugation and attachment of aptamer to a gold electrode, respectively. The sensor achieves a clinically meaningful cortisol concentration ranging from 0.05 ng/mL to 100 ng/mL and provides good selectivity when challenged with structurally similar targets. The reagent-less measurement capability was also demonstrated using an undiluted human serum. The newly developed cortisol sensor can enable the systemic cortisol measurement for providing insights into cortisol related clinical conditions and medical treatments.

通过检测特定的生化标志物（如皮质醇）来持续监测压力在各种疾病的早期检测中起着至关重要的作用。涉及结合诱导的构象变化的电化学适体传感器允许对生物标志物进行连续测量。在此背景下开发了一种基于适配体的无试剂生物传感平台，该平台允许连续和实时的皮质醇测量。适配体与亚甲蓝结合，亚甲蓝作为氧化还原报告分子探测传感器表面上的皮质醇定量结合。皮质醇特异性适配体分别用胺和硫醇官能团进行化学修饰，以促进氧化还原报告分子偶联和适配体与金电极的连接。该传感器实现了临床上有意义的皮质醇浓度，范围为 0。05 ng/mL 至 100 ng/mL，并在使用结构相似的靶标时提供良好的选择性。使用未稀释的人血清也证明了无试剂测量能力。新开发的皮质醇传感器可以实现全身皮质醇测量，从而深入了解皮质醇相关的临床状况和药物治疗。