Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
Nanotechnology. 2012 Aug 10;23(31):315502. doi: 10.1088/0957-4484/23/31/315502. Epub 2012 Jul 13.
A novel nanohybrid ratiometric fluorescence probe comprised of fluorescent graphene oxide and quantum dots (QDs) has been prepared by bringing CdTe QDs of red fluorescence and fluorescent graphene oxide (FGO) of blue fluorescence together through electrostatic attraction and hydrogen bonding interaction between their surface functional groups including carboxyl and amine groups. The nanohybrid ratiometric fluorescence probe exhibits dual emissions at 450 and 650 nm under a single excitation wavelength and shows high sensitivity for the detection of ferrous ions in the presence of H₂O₂. Ferrous ions reacts with H₂O₂ to generate very reactive hydroxyl radicals which possess a strong oxidizing nature and easily capture the electrons from the surfaces of the CdTe QDs, leading to fluorescence quenching of the QDs and no effect on the fluorescence of the graphene oxide, which hence results in a great change of the fluorescence ratio. Moreover, the ratiometric fluorescence probe is not only extremely sensitive to ferrous ions, but is also selective over other biologically relevant metal cations. The changes of fluorescence colour ratios can be used for visual sensing applications for ferrous ions in the presence of hydrogen peroxide, and can also be used for the indication of the existence of hydrogen peroxide.
一种新型的比率型荧光纳米杂化探针，由红色荧光的 CdTe 量子点和蓝色荧光的荧光氧化石墨烯（FGO）通过静电吸引和氢键相互作用结合而成，其表面官能团包括羧基和氨基。该纳米杂化比率型荧光探针在单一激发波长下表现出 450nm 和 650nm 处的双发射峰，并在存在 H₂O₂的情况下对亚铁离子的检测具有高灵敏度。亚铁离子与 H₂O₂反应生成具有强氧化性的非常活泼的羟基自由基，容易从 CdTe 量子点的表面夺取电子，导致量子点的荧光猝灭，而对氧化石墨烯的荧光没有影响，从而导致荧光比率发生很大变化。此外，比率型荧光探针不仅对亚铁离子极其敏感，而且对其他生物相关的金属阳离子也具有选择性。荧光颜色比率的变化可用于在存在过氧化物的情况下对亚铁离子进行可视化传感应用，也可用于指示过氧化物的存在。
