CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
Phys Chem Chem Phys. 2014 Jan 28;16(4):1576-82. doi: 10.1039/c3cp54317j. Epub 2013 Dec 6.
Free-standing optical hybrid film which is composed of positively-charged polyethylenimine-coated NaYF4:Yb,Er nanoparticles and negatively-charged graphene oxide (GO) has been developed to measure pH based on the pH-dependent luminescence quenching effect caused by GO. The isothermal titration calorimetry analyses indicate that the interaction between GO and NaYF4:Yb,Er nanoparticles becomes stronger with increasing pH, leading to a more significant fluorescence quenching of NaYF4:Yb,Er nanoparticles at high pH values. The excellent mechanical properties of the hybrid film endow the thin-film pH sensor with better repeatability and higher stability during the measurements. Quantitatively, the upconversion luminescence intensity of the hybrid film exhibits a linear trend over the pH range of 5.00-8.00. Because of excitation with a 980 nm laser, as expected, the hybrid film sensor is also sensitive to the urine measurements with reduced background absorption. In addition to its good biocompatibility, our free-standing hybrid film sensor would be a promising candidate for biological, medical, and pharmaceutical applications.
已开发出一种独立式光学混合薄膜，它由带正电荷的聚乙烯亚胺包覆的 NaYF4:Yb,Er 纳米粒子和带负电荷的氧化石墨烯 (GO) 组成，可基于 GO 引起的与 pH 值相关的发光猝灭效应来测量 pH 值。等温热力学滴定分析表明，GO 与 NaYF4:Yb,Er 纳米粒子之间的相互作用随 pH 值的增加而增强，导致在高 pH 值下 NaYF4:Yb,Er 纳米粒子的荧光猝灭更显著。混合薄膜的优异机械性能使薄膜 pH 传感器在测量过程中具有更好的重复性和更高的稳定性。定量地，混合薄膜的上转换发光强度在 pH 5.00-8.00 范围内呈线性趋势。由于使用 980nm 激光激发，正如预期的那样，混合薄膜传感器对尿液测量也具有较低背景吸收的灵敏度。除了良好的生物相容性外，我们的独立式混合薄膜传感器有望成为生物、医学和制药应用的有前途的候选者。
