School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, People's Republic of China. School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, People's Republic of China.
Methods Appl Fluoresc. 2017 May 5;5(2):024010. doi: 10.1088/2050-6120/aa6e0d.
A novel luminescence 'Turn-On' nanoplatform for the sensitive sensing of Ag was fabricated based on luminescence resonance energy transfer technique between sodium citrate functionalized upconversion nanoparticles (Cit-UCNPs, energy donor) and graphene quantum dots (GQDs, energy acceptor). Amino-labeled single-stranded DNA (NH-ssDNA) containing a number of cytosine (C) was conjugated on the surface of the Cit-UCNPs to capture Ag ions. Due to the π-π stacking interaction between NH-ssDNA and GQDs, the upconversion luminescence can be quenched. However, upon the addition of Ag, the π-π stacking interaction weakens due to the formation of the hairpin structure of C-Ag-C on the UCNPs. As a result, GQDs will leave the surface of the UCNPs and the upconversion luminescence can be enhanced (Turn-On). Based on this fact, the sensor was developed for the detection of Ag with a linear concentration range from 2 × 10 to 1 μM and a detection limit as low as 60 pM. The assay method is fairly simple with high selectivity and sensitivity, which can be used for the determination of Ag in environmental water samples.
一种基于上转换纳米粒子（Cit-UCNPs，能量供体）和石墨烯量子点（GQDs，能量受体）之间的荧光共振能量转移技术，构建了一种用于灵敏检测 Ag 的新型荧光“开启”纳米平台。表面修饰有柠檬酸根的上转换纳米粒子（Cit-UCNPs）通过氨基标记的单链 DNA（NH-ssDNA）捕获 Ag 离子，NH-ssDNA 上含有大量的胞嘧啶（C）。由于 NH-ssDNA 与 GQDs 之间的π-π堆积相互作用，上转换荧光可以被猝灭。然而，当加入 Ag 时，由于 UCNPs 上形成了 C-Ag-C 的发夹结构，这种π-π堆积相互作用会减弱。因此，GQDs 将离开 UCNPs 的表面，上转换荧光得到增强（开启）。基于这一事实，该传感器用于检测 Ag，线性浓度范围为 2×10 到 1 μM，检测限低至 60 pM。该检测方法非常简单，具有高选择性和灵敏度，可用于环境水样中 Ag 的测定。
