Autonomous, Real-Time Monitoring Electrochemical Aptasensor for Circadian Tracking of Cortisol Hormone in Sub-microliter Volumes of Passively Eluted Human Sweat
Autonomous, Real-Time Monitoring Electrochemical Aptasensor for Circadian Tracking of Cortisol Hormone in Sub-microliter Volumes of Passively Eluted Human Sweat
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DOI：
10.1021/acssensors.0c01754
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发表时间：
2021-01-22
期刊：
影响因子：
8.9
通讯作者：
Prasad, Shalini
中科院分区：
文献类型：
--
作者：
Ganguly, Antra;Lin, Kai Chun;Prasad, Shalini
这项拟议的工作包括开发一种自主的、无标记的电化学传感器，用于实时监测亚微升汗液中自然表达的皮质醇水平，并延长感应期约8小时。高特异性单链DNA(SsDNA)适配子用于亲和捕获汗液中洗脱的皮质醇激素。汗液中存在的皮质醇与适体捕获探针结合，该探针改变电极-缓冲液界面的构象并调节电化学性质，这是通过对整个生理汗液pH的动态光散射研究来研究的。利用衰减全反射傅里叶变换红外光谱和紫外-可见光谱优化了传感器堆叠中各元素的结合化学。用非法拉第电化学阻抗谱对传感器进行了校正，动态范围为1-256 ng/mL。得到R-2为0.97，输出信号范围为20-50%。通过连续给药实验校准传感器的时间变化，研究了皮质醇水平的动态变化跟踪。由于交叉反应干扰和非特定的缓冲成分，传感器没有表现出对噪声的显著敏感性。在表面电荷行为和非法拉迪克生物传感方面，将所开发的aptasensor与先前建立的皮质醇免疫传感器的性能进行了比较。适配子传感器表现出更高的信噪比，更好的分辨率，并且在与皮质醇免疫传感器相同的输入范围内具有更大的输出范围。通过人体受试者研究，验证了将开发的适配方案部署为连续的生活方式和性能监测器的可行性。
The proposed work involves the development of an autonomous, label-free electrochemical sensor for real-time monitoring of cortisol levels expressed naturally in sub-microliter sweat volumes, for prolonged sensing periods of similar to 8 h. Highly specific single-stranded DNA (ssDNA) aptamer is used for affinity capture of cortisol hormone eluted in sweat dynamically. The cortisol present in sweat binds to the aptamer capture probe that changes conformation and modulates electrochemical properties at the electrode-buffer interface, which was studied using dynamic light scattering studies for the entire physiological sweat pH. Attenuated total reflectance-Fourier transform infrared spectroscopy and UV-vis spectroscopy were used to optimize the binding chemistry of the elements of the sensor stack. Nonfaradaic electrochemical impedance spectroscopy was used to calibrate the sensor for a dynamic range of 1-256 ng/mL. An R-2 of 0.97 with an output signal range of 20-50% was obtained. Dynamic cortisol level variation tracking was studied using continuous dosing experiments to calibrate the sensor for temporal variation. The sensor did not show significant susceptibility to noise due to cross-reactive interferents and nonspecific buffer constituents. The performance of the developed aptasensor was compared with the previously established cortisol immunosensor in terms of surface charge behavior and nonfaradaic biosensing. The aptamer sensor shows a higher signal-to-noise ratio, better resolution, and has a larger output range for the same input range as the cortisol immunosensor. The feasibility of deploying the developed aptasensing scheme as continuous lifestyle and performance monitors was validated through human subject studies.