Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
Bioelectrochemistry. 2013 Dec;94:87-93. doi: 10.1016/j.bioelechem.2013.09.002. Epub 2013 Sep 13.
The thionine-graphene (THi-GR, positively charged) nanocomposite was successfully synthesized as a good biocompatible matrix for ds-DNA which acted as a chiral selector to construct an electrochemical chiral biosensor for Tryptophan (Trp) enantiomers sensing with the assistance of Cu(II). The nano-bionic interface was constructed as follows: Firstly, the nanocomposite was dropped on the surface of glassy carbon electrode (GCE), and then ds-DNA (negatively charged) was immobilized onto the nanocomposite film via the opposite-charged adsorption techniques. This biofunctionalized nanocomposite was characterized with scanning electron microscopy (SEM), ultraviolet-visible (UV-vis) spectrometry and cyclic voltammetry (CV). The chiral biosensor was employed to study the recognition effect between ds-DNA and Trp enantiomers by CV. The results show that larger electrochemical response was obtained from l-Trp when Cu(II) was present, indicating this strategy could be employed to enantioselectively recognize Trp enantiomers. Under optimum conditions, the chiral biosensor exhibited a good linear response to Trp enantiomers in the range of the concentration of [Cu(II)(Trp)2] from 5.0 × 10(-4) to 2.5mM with a low limit of detection of 0.17 μM (S/N=3). The binding constant was calculated to be 2.97 × 10(3)M(-1) for [Cu(II)(l-Trp)2] and 2.50 × 10(2)M(-1) for [Cu(II)(d-Trp)2].
硫堇-石墨烯（THi-GR，带正电荷）纳米复合材料成功合成，作为 ds-DNA 的良好生物相容性基质，ds-DNA 作为手性选择剂，在 Cu(II) 的协助下构建用于色氨酸（Trp）对映体检测的电化学手性生物传感器。纳米仿生界面构建如下：首先，将纳米复合材料滴在玻碳电极（GCE）表面，然后通过相反电荷吸附技术将 ds-DNA（带负电荷）固定在纳米复合材料薄膜上。用扫描电子显微镜（SEM）、紫外可见（UV-vis）光谱和循环伏安法（CV）对这种生物功能化纳米复合材料进行了表征。采用手性生物传感器通过 CV 研究 ds-DNA 与 Trp 对映体之间的识别效果。结果表明，当存在 Cu(II) 时，l-Trp 获得了更大的电化学响应，表明该策略可用于对映选择性识别 Trp 对映体。在最佳条件下，手性生物传感器对 [Cu(II)(Trp)2] 浓度在 5.0×10(-4) 至 2.5mM 范围内的 Trp 对映体表现出良好的线性响应，检测限低至 0.17 μM（S/N=3）。计算得到 [Cu(II)(l-Trp)2] 的结合常数为 2.97×10(3)M(-1)，[Cu(II)(d-Trp)2] 的结合常数为 2.50×10(2)M(-1)。
