State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
Dalton Trans. 2020 Dec 21;49(47):17200-17206. doi: 10.1039/d0dt03555f. Epub 2020 Nov 17.
The development of fluorescent sensors based on lanthanide-doped luminescent nanoparticles has increased their application in biomarker detection. Lanthanide-doped upconversion nanoparticles (UCNPs) have been explored as one of the most promising sensors owing to their merits such as excellent photostability, zero background auto-fluorescence, and reduced side effects of near-infrared triggered treatments. However, traditional upconversion luminescence assay based on direct Fluorescence Resonance Energy Transfer (FRET) between the target molecules and surface of UCNPs encounters low detection accuracy due to superficial adsorption interactions. In this work, we use a molecularly imprinting technique to achieve the specific interaction between UCNPs and molecules for accurate sensing. We demonstrate this by synthesizing a nanostructure with a molecularly imprinted polymer at the surface of UCNPs, in which the imprinted cavities can specifically capture the target molecule of rhodamine B. The upconversion signal changes in relation to the molecule concentration due to FRET. Quantitative analysis shows that the fluorescence-quenching rate is consistent with the Stern-Volmer equation, resulting in a limit of detection of 6.27 μg mL. Our fluorescence sensing approach integrates the advantages of both nonlinear upconversion and molecular imprinting technologies, showing great potential for the detection of specific molecules.
基于镧系掺杂发光纳米粒子的荧光传感器的发展增加了它们在生物标志物检测中的应用。镧系掺杂上转换纳米粒子（UCNPs）由于其优异的光稳定性、零背景自荧光和减少近红外触发治疗的副作用等优点，已被探索作为最有前途的传感器之一。然而，基于目标分子与 UCNPs 表面之间的直接荧光共振能量转移（FRET）的传统上转换发光分析由于表面吸附相互作用而导致检测精度低。在这项工作中，我们使用分子印迹技术实现 UCNPs 与分子之间的特异性相互作用，以实现准确的传感。我们通过在 UCNPs 表面合成具有分子印迹聚合物的纳米结构来证明这一点，其中印迹腔可以特异性地捕获罗丹明 B 的目标分子。由于 FRET，上转换信号随分子浓度的变化而变化。定量分析表明，荧光猝灭率与 Stern-Volmer 方程一致，导致检测限为 6.27μg mL。我们的荧光传感方法结合了非线性上转换和分子印迹技术的优势，在特定分子的检测方面显示出巨大的潜力。
