Department of Mechanical Engineering, Texas Tech University, 2500 Broadway, PO Box 41021, Lubbock, TX 79409-1021, USA.
Nanotechnology. 2012 Aug 24;23(33):335707. doi: 10.1088/0957-4484/23/33/335707. Epub 2012 Aug 3.
In this paper, a 'green' and safe hydrothermal method has been used to reduce graphene oxide and produce hemin modified graphene nanosheet (HGN) based electrochemical biosensors for the determination of l-tyrosine levels. The as-fabricated HGN biosensors were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FTIR) spectra and thermogravimetric analysis (TGA). The experimental results indicated that hemin was successfully immobilized on the reduced graphene oxide nanosheet (rGO) through π-π interaction. TEM images and EDX results further confirmed the attachment of hemin on the rGO nanosheet. Cyclic voltammetry tests were carried out for the bare glass carbon electrode (GCE), the rGO electrode (rGO/GCE), and the hemin-rGO electrode (HGN/GCE). The HGN/GCE based biosensor exhibits a tyrosine detection linear range from 5 × 10(-7) M to 2 × 10(-5) M with a detection limitation of 7.5 × 10(-8) M at a signal-to-noise ratio of 3. The sensitivity of this biosensor is 133 times higher than that of the bare GCE. In comparison with other works, electroactive biosensors are easily fabricated, easily controlled and cost-effective. Moreover, the hemin-rGO based biosensors demonstrate higher stability, a broader detection linear range and better detection sensitivity. Study of the oxidation scheme reveals that the rGO enhances the electron transfer between the electrode and the hemin, and the existence of hemin groups effectively electrocatalyzes the oxidation of tyrosine. This study contributes to a widespread clinical application of nanomaterial based biosensor devices with a broader detection linear range, improved stability, enhanced sensitivity and reduced costs.
在本文中，采用了一种“绿色”且安全的水热法还原氧化石墨烯，并制备了基于血红素修饰的石墨烯纳米片（HGN）的电化学生物传感器，用于测定 l-酪氨酸的含量。所制备的 HGN 生物传感器通过紫外-可见吸收光谱、荧光光谱、傅里叶变换红外光谱（FTIR）和热重分析（TGA）进行了表征。实验结果表明，血红素通过π-π相互作用成功固定在还原氧化石墨烯纳米片（rGO）上。TEM 图像和 EDX 结果进一步证实了血红素固定在 rGO 纳米片上。对裸玻碳电极（GCE）、rGO 电极（rGO/GCE）和血红素-rGO 电极（HGN/GCE）进行了循环伏安测试。基于 HGN/GCE 的生物传感器在信号噪声比为 3 时，对酪氨酸的检测线性范围为 5×10(-7) M 至 2×10(-5) M，检测限为 7.5×10(-8) M。该生物传感器的灵敏度比裸 GCE 高 133 倍。与其他工作相比，该电活性生物传感器易于制备、易于控制且具有成本效益。此外，基于血红素-rGO 的生物传感器具有更高的稳定性、更宽的检测线性范围和更好的检测灵敏度。氧化方案的研究表明，rGO 增强了电极和血红素之间的电子转移，血红素基团的存在有效地电催化了酪氨酸的氧化。本研究为基于纳米材料的生物传感器器件的广泛临床应用做出了贡献，这些器件具有更宽的检测线性范围、提高的稳定性、增强的灵敏度和降低的成本。
