Physiological and emotional stress affects the regulation of cortisol secretion, a routine process in circadian rhythm. Regular monitoring of cortisol level as a biomarker in the blood stream becomes vital to determine cortisol-related diseases. This study reports immuno-probed graphene nanoplatelets on electrolyte-gated field-effect transistor (EGFET) biosensor for cortisol determination in human serum. Solution-processed graphene nanoplatelets were evidenced on the surface by Raman spectroscopy analysis and utilized as the transducing element on the field-effect transistor. Further, confirmed the binding events of the antibody on graphene nanoplatelets using X-Ray Photoelectron Spectroscopy and characterized the electrostatic gating effect of cortisol and intermediate functionalization on graphene nanoplatelets-EGFET. The biosensor exhibited good sensitivity of 72.30 µA.(g/mL)⁻¹ in a linear range between 1.00 pg/mL to 10.00 ng/mL, with a limit of detection (LOD) of 0.85 pg/mL. Confirmation with binding events on the biosensor was done using the relevant molecules, progesterone, cortisone, and corticosterone, and found to be selective towards cortisol. Cortisol was also successfully detected with interference by the human serum, suggesting the capability of graphene nanoplatelets-EGFET sensor for determining cortisol in a complex matrix.

生理和情绪压力会影响皮质醇分泌的调节，这是昼夜节律的一个常规过程。定期监测皮质醇水平作为血液中的生物标志物对于确定皮质醇相关疾病至关重要。这项研究报告了电解质门控场效应晶体管（EGFET）生物传感器上用于人体血清皮质醇测定的免疫探测石墨烯纳米片。通过拉曼光谱分析在表面上证实了溶液处理的石墨烯纳米片，并将其用作场效应晶体管上的转导元件。此外，使用X射线光电子能谱证实了抗体在石墨烯纳米血小板上的结合事件，并表征了皮质醇的静电门控效应和石墨烯纳米血小板-EGFET的中间功能化。^-1在1.00 pg / mL至10.00 ng / mL的线性范围内，检测极限（LOD）为0.85 pg / mL。使用相关分子，孕酮，可的松和皮质酮对生物传感器上的结合事件进行确认，发现对皮质醇具有选择性。还成功地通过人血清干扰检测了皮质醇，这表明石墨烯纳米血小板-EGFET传感器具有测定复杂基质中皮质醇的能力。