Highly sensitive and selective biosensors for accurate determination of specific protein biomarkers at low levels in serum are a prerequisite for the present healthcare systems. Therefore, here we developed a label-free impedimetric method for tumor necrosis factor-alpha (TNF-α) detection using reduced graphene oxide (RGO) with gold nanoparticles (AuNP) on an indium tin oxide (ITO) microdisk electrodes. The detection mechanism relies on resistance change occurs due to [Fe(CN)₆]^3−/4− redox probe movement towards the conductive channels of the AuNP-RGO films gated by the recognition of the target biomarker by its anti-TNF-α antibody. The conductivity of the AuNP-RGO structures enhanced by 10-fold in comparison with bare electrode chips. The observed resistance changes at 2 Hz (ΔR _{at 2Hz}) enabled the quantification of various concentrations of TNF-α in human serum (C_HS-TNF-α). The antibody-adsorbed electrode showed a good increment of resistance change (ΔR) with additions of antigen concentration. The sensor possesses a linear range of 1–1000 pg/ml had a detection limit of 0.67 pg/ml (38.51 fM) and 0.78 pg/ml (44.83 fM) in PBS and human serum, respectively.

用于精确测定血清中低水平的特定蛋白质生物标志物的高度灵敏和选择性的生物传感器是本医疗系统的先决条件。因此，在这里，我们开发了一种无标记的阻抗法，用于在氧化铟锡（ITO）微盘电极上使用还原的氧化石墨烯（RGO）和金纳米颗粒（AuNP）进行肿瘤坏死因子-α（TNF-α）检测。检测机制依赖于由于[Fe（CN）₆ ] ^{3- / 4-}氧化还原探针向AuNP-RGO膜的导电通道移动而引起的电阻变化，该AuNP-RGO膜通过其抗TNF-α识别目标生物标记而被门控抗体。与裸电极芯片相比，AuNP-RGO结构的电导率提高了10倍。观察到的电阻在2 Hz（ΔR_{在2Hz的频率下}）可以定量测定人血清中各种浓度的TNF-α（_CHS-TNF-α）。抗体吸附电极显示出随着抗原浓度的增加电阻变化（ΔR）的良好增加。该传感器的线性范围为1–1000 pg / ml，在PBS和人血清中的检出限分别为0.67 pg / ml（38.51 fM）和0.78 pg / ml（44.83 fM）。