Glial fibrillary acidic protein (GFAP) is as an intermediate filament protein expressed by certain cells in the central nervous system (CNS). GFAP has been recognized as a reliable biomarker of CNS injury. However, due to the absence of rapid and easy-to-use assays for the detection of CNS injury biomarkers, measuring GFAP levels to identify CNS injury has not attained widespread clinical implementation. In the present work, we developed a polyethylenimine (PEI) coated graphene screen-printed electrode and used it for highly sensitive immunosensing of GFAP. Covalent binding of GFAP antibody to the PEI-modified electrode surface along with electrochemical impedance spectroscopy was used for detecting the change in the electrical conductivity of the electrodes. A highly linear response was recorded for various GFAP concentrations. Quantitative, selective, and label-free detection was achieved in the dynamic range of 1 pg mL^–1 to 100 ng mL^–1 for GFAP spiked in phosphate buffer saline, artificial cerebrospinal fluid, and human blood serum. The performance of the immunosensor was further validated and correlated by testing samples with the commercially available enzyme-linked immunosorbent assay method. This functionalized electrode could be used clinically for rapid detection and monitoring of CNS injury.

中文翻译：

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聚乙烯亚胺修饰的氧化石墨烯电化学免疫传感器检测中枢神经系统损伤中胶质纤维酸性蛋白

胶质纤维酸性蛋白（GFAP）是中枢神经系统（CNS）中某些细胞表达的中间丝蛋白。GFAP被公认为中枢神经系统损伤的可靠生物标志物。然而，由于缺乏用于检测CNS损伤生物标志物的快速且易于使用的测定法，测量GFAP水平以鉴定CNS损伤尚未获得广泛的临床实施。在目前的工作中，我们开发了一种聚乙烯亚胺（PEI）涂层的石墨烯丝网印刷电极，并将其用于GFAP的高度灵敏的免疫传感。GFAP抗体与PEI修饰的电极表面的共价结合以及电化学阻抗谱用于检测电极电导率的变化。记录了各种GFAP浓度的高度线性响应。定量的^–1到100 ng mL ^–1的GFAP加在磷酸盐缓冲液，人工脑脊液和人血清中。通过使用可商购的酶联免疫吸附测定方法测试样品，进一步验证并关联了免疫传感器的性能。该功能化电极可在临床上用于CNS损伤的快速检测和监测。