Tumor necrosis factor (TNF-α) is a representative cytokine family known to induce multiple signaling cascades leading to various cellular responses, such as cell death, survival, and differentiation. It has been reported that blocking the action of TNF-α in various diseases can improve disease prognosis. Therefore, it is important to monitor TNF-α in patient plasma and properly regulate its action. In this study, we report a label-free electrochemical biosensor consisting of a multifunctional DNA 4-way junction (MF-4WJ) for TNF-α detection in human serum. MF-4WJ does not require additional labeling and signal amplification processes. The electrochemical properties of functionalized MF-4WJ were evaluated by cyclic voltammetry (CV) in the presence of Ag⁺ intercalated between the mismatched sequences of MF-aptamers as redox-active species. Afterward, CV was carried out to evaluate the performance of the fabricated biosensor. The proposed label-free electrochemical biosensor was able to effectively detect TNF-α in a dynamic range of 0.15 pg/ml to 150 ng/ml. Limit of detection (LOD) was at 0.07 pg/ml in HEPES. Moreover, it was confirmed that even in 10% diluted human serum, TNF-α could be detected in an excellent dynamic range of 0.15 pg/ml to ∼ 15 ng/ml and LOD was at 0.14 pg/ml in 10% diluted human serum.

肿瘤坏死因子 (TNF-α) 是一种具有代表性的细胞因子家族，已知可诱导多种信号级联反应，导致各种细胞反应，例如细胞死亡、存活和分化。已有报道阻断TNF-α在多种疾病中的作用可改善疾病预后。因此，监测患者血浆中的 TNF-α 并适当调节其作用非常重要。在这项研究中，我们报告了一种无标记电化学生物传感器，该传感器由多功能 DNA 4 通接头 (MF-4WJ) 组成，用于检测人血清中的 TNF-α。MF-4WJ 不需要额外的标记和信号放大过程。^{在 Ag +}存在下通过循环伏安法 (CV) 评估功能化 MF-4WJ 的电化学性能插入在 MF 适体的错配序列之间作为氧化还原活性物质。之后，进行CV以评估制造的生物传感器的性能。所提出的无标记电化学生物传感器能够在 0.15 pg/ml 至 150 ng/ml 的动态范围内有效检测 TNF-α。HEPES 中的检测限 (LOD) 为 0.07 pg/ml。此外，证实即使在 10% 稀释的人血清中，也可以在 0.15 pg/ml 至 ∼ 15 ng/ml 的极好动态范围内检测到 TNF-α，在 10% 稀释的人血清中 LOD 为 0.14 pg/ml .