Department of Chemistry and Biochemistry, University of California Santa Barbara , Santa Barbara, California 93106, United States.
Center for Bioengineering, University of California Santa Barbara , Santa Barbara, California 93106, United States.
Anal Chem. 2017 Nov 21;89(22):12185-12191. doi: 10.1021/acs.analchem.7b02830. Epub 2017 Nov 10.
The electrochemical, aptamer-based (E-AB) sensor platform provides a modular approach to the continuous, real-time measurement of specific molecular targets (irrespective of their chemical reactivity) in situ in the living body. To achieve this, however, requires the fabrication of sensors small enough to insert into a vein, which, for the rat animal model we employ, entails devices less than 200 μm in diameter. The limited surface area of these small devices leads, in turn, to low faradaic currents and poor signal-to-noise ratios when deployed in the complex, fluctuating environments found in vivo. In response we have developed an electrochemical roughening approach that enhances the signaling of small electrochemical sensors by increasing the microscopic surface area of gold electrodes, allowing in this case more redox-reporter-modified aptamers to be packed onto the surface, thus producing significantly improved signal-to-noise ratios. Unlike previous approaches to achieving microscopically rough gold surfaces, our method employs chronoamperometric pulsing in a 5 min etching process easily compatible with batch manufacturing. Using these high surface area electrodes, we demonstrate the ability of E-AB sensors to measure complete drug pharmacokinetic profiles in live rats with precision of better than 10% in the determination of drug disposition parameters.
电化学适体传感器(E-AB)平台为在活体中连续、实时原位测量特定分子靶标（无论其化学反应性如何）提供了一种模块化方法。然而，要实现这一目标，需要制造出足够小的传感器插入静脉，对于我们使用的大鼠动物模型，这需要直径小于 200μm 的设备。这些小设备的有限表面积导致在体内复杂波动的环境中部署时法拉第电流低且信号噪声比差。为了应对这一挑战，我们开发了一种电化学粗糙化方法，通过增加金电极的微观表面积来增强小电化学传感器的信号，从而在这种情况下可以将更多的氧化还原报告修饰适体组装到表面上，从而产生显著改善的信号噪声比。与以前实现微观粗糙金表面的方法不同，我们的方法在 5 分钟的蚀刻过程中使用计时安培法脉冲，很容易与批量制造兼容。使用这些高表面积电极，我们展示了 E-AB 传感器在活体大鼠中测量完整药物药代动力学曲线的能力，在确定药物处置参数时，其精密度优于 10%。
