Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.
Center for Bioengineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.
Anal Bioanal Chem. 2019 Jul;411(19):4629-4635. doi: 10.1007/s00216-019-01645-0. Epub 2019 Feb 22.
The field of precision medicine-the possibility to accurately tailor pharmacological treatments to each specific patient-would be significantly advanced by the ability to rapidly, conveniently, and cost-effectively measure biomarkers directly at the point of care. Electrochemical aptamer-based (E-AB) sensors appear a promising approach to this end due to their low cost, ease of use, and good analytical performance in complex clinical samples. Thus motivated, we present here the development of an E-AB sensor for the measurement of the amino acid L-tryptophan, a diagnostic marker indicative of a number of metabolic and mental health disorders, in urine. The sensor employs a previously reported DNA aptamer able to recognize the complex formed between tryptophan and a rhodium-based receptor. We adopted the aptamer to the E-AB sensing platform by truncating it, causing it to undergo a binding-induced conformational change, modifying it with a redox-reporting methylene blue, and attaching it to an interrogating electrode. The resulting sensor is able to measure tryptophan concentrations in the micromolar range in minutes and readily discriminates between its target and other aromatic and non-aromatic amino acids. Using it, we demonstrate the measurement of clinically relevant tryptophan levels in synthetic urine in a process requiring only a single dilution step. The speed and convenience with which this is achieved suggest that the E-AB platform could significantly improve the ease and frequency with which metabolic diseases are monitored. Graphical Abstract.
精准医学领域——能够将药物治疗精确地针对每个特定患者——如果能够在护理点快速、方便且具有成本效益地直接测量生物标志物，那么该领域将取得重大进展。电化学适体传感器（E-AB）似乎是一种很有前途的方法，因为它们成本低、使用方便，并且在复杂的临床样本中具有良好的分析性能。受此启发，我们在此开发了一种用于测量氨基酸 L-色氨酸的 E-AB 传感器，L-色氨酸是许多代谢和心理健康障碍的诊断标志物，可在尿液中检测。该传感器采用了先前报道的能够识别色氨酸与基于铑的受体形成的复合物的 DNA 适体。我们通过截断适体将其应用于 E-AB 传感平台，从而使其发生结合诱导的构象变化，用报告性的氧化还原甲基蓝对其进行修饰，并将其连接到检测电极上。由此产生的传感器能够在数分钟内测量出微摩尔范围内的色氨酸浓度，并能够轻松区分其目标物与其他芳香族和非芳香族氨基酸。使用该传感器，我们在仅需单个稀释步骤的过程中，在合成尿液中测量了具有临床相关性的色氨酸水平。实现这一目标的速度和便利性表明，E-AB 平台可以极大地提高代谢疾病监测的便利性和频率。示意图。
