Herein, a biosensor based on a reduced graphene oxide field effect transistor (rGO-FET) functionalized with the cascading enzymes arginase and urease was developed for the detection of L-arginine. Arginase and urease were immobilized on the rGO-FET sensing surface via electrostatic layer-by-layer assembly using polyethylenimine (PEI) as cationic building block. The signal transduction mechanism is based on the ability of the cascading enzymes to selectively perform chemical transformations and prompt local pH changes, that are sensitively detected by the rGO-FET. In the presence of L-arginine, the transistors modified with (PEI/urease(arginase)) multilayers showed a shift in the Dirac point due to the change in the local pH close to the graphene surface, produced by the catalyzed urea hydrolysis. The transistors were able to monitor L-arginine in the 10–1000 μM linear range with a LOD of 10 μM, displaying a fast response and a good long-term stability. The sensor showed stereospecificity and high selectivity in the presence of non-target amino acids. Taking into account the label-free, real-time measurement capabilities and the easily quantifiable, electronic output signal, this biosensor offers advantages over state-of-the-art L-arginine detection methods.

在本文中，基于L-精氨酸的检测，开发了基于被级联酶精氨酸酶和脲酶功能化的还原性氧化石墨烯场效应晶体管（rGO-FET）的生物传感器。精氨酸酶和脲酶通过聚乙烯亚胺（PEI）作为阳离子构件，通过静电的逐层组装固定在rGO-FET感应表面上。信号转导机制基于级联酶选择性地执行化学转化并提示局部pH改变的能力，这些能力被rGO-FET灵敏地检测到。在L的存在下-精氨酸，经（PEI /脲酶（精氨酸酶））多层修饰的晶体管由于催化尿素水解产生的接近石墨烯表面的局部pH值的变化，狄拉克点发生了位移。晶体管能够以10μM的LOD监测10–1000μM线性范围内的L-精氨酸，显示出快速的响应和良好的长期稳定性。在存在非目标氨基酸的情况下，传感器表现出立体特异性和高选择性。考虑到无标签的实时测量功能和易于量化的电子输出信号，该生物传感器提供了优于最新的L-精氨酸检测方法的优势。