Department of Chemistry, Razi University, Kermanshah, Iran.
Department of Chemistry, Razi University, Kermanshah, Iran.
Talanta. 2020 Sep 1;217:121093. doi: 10.1016/j.talanta.2020.121093. Epub 2020 Apr 29.
For the first time, we have successfully synthesized stable graphene nanosheets from graphite powder through sonication in the hemoglobin-capped gold nanoclusters (Hb@AuNCs) solution for biosensing application. This approach, as a simple method for the exfoliation and fragmentation of graphite in a nanocluster solution, enabled us to produce stable aqueous graphene dispersions at low cost and without the need for hazardous chemicals or tedious experimental procedures. In this method, Hb@AuNCs were used not only as stabilizing agent of graphene through non-covalent bonding, but also as dispersing agent of few-layer graphene nanosheets. The Hb@AuNCs stabilized graphene (Hb@AuNCs-G) was characterized by high resolution transmission electron microscopy (HRTEM), zeta-sizer and Raman spectroscopy. Then, the graphene nanosheets were applied as a novel versatile electrochemical platform for ultrasensitive biosensing of short DNA species of chronic myelogenous leukemia (CML) based on the "signal off" and "signal on" strategies. For this purpose, a single strand DNA (ssDNA) was immobilized on the Hb@AuNCs-G/AuNPs modified electrode surface and acted as the biorecognition element. Methylene blue (MB), as the signaling probe, was then intercalated into the ssDNA. The intercalated MB was liberated upon interaction with the synthetic complementary DNA (cDNA, target), thereby resulting in the apparent reduction of MB redox signal. This designed "signal off" sensing system enabled the voltammetric determination of the target cDNA over a dynamic linear range (DLR) of 0.1 fM to 10 pM with a limit of detection (LOD) of 0.037 fM. In the "signal on" strategy, the response to the cDNA was detected by monitoring the change in the electron transfer resistance (R) using the ferro/ferricyanide system as a redox probe. The charge transfer resistance of the probe was found to increase linearly with increasing concentration of target cDNA in the range of 0.1 fM-10 pM with a limit of detection of 0.030 fM. Finally, the selectivity and feasibility of genosensor was evaluated by the analysis of derived nucleotides from mismatched sequences and the clinical samples of patients with leukemia as real samples, respectively.
我们首次通过超声在血红蛋白封端的金纳米簇（Hb@AuNCs）溶液中成功地将石墨粉合成了稳定的石墨烯纳米片，可用于生物传感应用。这种方法是一种在纳米簇溶液中使石墨剥落和碎裂的简单方法，使我们能够以低成本且无需使用危险化学品或繁琐的实验程序来生产稳定的水性石墨烯分散体。在这种方法中，Hb@AuNCs 不仅通过非共价键作为石墨烯的稳定剂，而且还作为少层石墨烯纳米片的分散剂。Hb@AuNCs 稳定的石墨烯（Hb@AuNCs-G）通过高分辨率透射电子显微镜（HRTEM）、zeta 粒径仪和拉曼光谱进行了表征。然后，将石墨烯纳米片用作新型多功能电化学平台，用于基于“信号关闭”和“信号开启”策略对慢性髓系白血病（CML）的短 DNA 种进行超灵敏生物传感。为此，将单链 DNA（ssDNA）固定在 Hb@AuNCs-G/AuNPs 修饰电极表面上，并用作生物识别元件。然后，将亚甲基蓝（MB）作为信号探针插入 ssDNA 中。当与合成的互补 DNA（cDNA，靶标）相互作用时，插入的 MB 被释放，从而导致 MB 氧化还原信号明显减少。这种设计的“信号关闭”传感系统使伏安法能够在 0.1 fM 至 10 pM 的动态线性范围内（DLR）检测目标 cDNA，检测限（LOD）为 0.037 fM。在“信号开启”策略中，通过使用铁氰化亚铁系统作为氧化还原探针来监测电子转移电阻（R）的变化来检测对 cDNA 的响应。发现探针的电荷转移电阻随着靶 cDNA 浓度在 0.1 fM-10 pM 范围内呈线性增加，检测限为 0.030 fM。最后，通过分析来自错配序列的衍生核苷酸和来自白血病患者的临床样本分别评估了基因传感器的选择性和可行性。
