Department Physical Chemistry, Faculty of Pharmacy, Unidad de Excelencia de Química Aplicada a la Biomedicinay Medioambiente (UEQABM), University of Granada, Campus Cartuja, 18071 Granada, Spain.
Sensors (Basel). 2019 Nov 16;19(22):4992. doi: 10.3390/s19224992.
In the last few years, quantum dot (QD) nanoparticles have been employed for bioimaging and sensing due to their excellent optical features. Most studies have used photoluminescence (PL) intensity-based techniques, which have some drawbacks, especially when working with nanoparticles in intracellular media, such as fluctuations in the excitation power, fluorophore concentration dependence, or interference from cell autofluorescence. Some of those limitations can be overcome with the use of time-resolved spectroscopy and fluorescence lifetime imaging microscopy (FLIM) techniques. In this work, CdSe/ZnS QDs with long decay times were modified with aminophenylboronic acid (APBA) to achieve QD-APBA conjugates, which can act as glucose nanosensors. The attachment of the boronic acid moiety on the surface of the nanoparticle quenched the PL average lifetime of the QDs. When glucose bonded to the boronic acid, the PL was recovered and its lifetime was enhanced. The nanosensors were satisfactorily applied to the detection of glucose into MDA-MB-231 cells with FLIM. The long PL lifetimes of the QD nanoparticles made them easily discernible from cell autofluorescence, thereby improving selectivity in their sensing applications. Since the intracellular levels of glucose are related to the metabolic status of cancer cells, the proposed nanosensors could potentially be used in cancer diagnosis.
在过去的几年中，由于其出色的光学特性，量子点（QD）纳米粒子已被用于生物成像和传感。大多数研究都使用基于光致发光（PL）强度的技术，但这些技术存在一些缺点，特别是在细胞内介质中使用纳米粒子时，例如激发功率波动、荧光团浓度依赖性或细胞自发荧光的干扰。其中一些限制可以通过使用时间分辨光谱和荧光寿命成像显微镜（FLIM）技术来克服。在这项工作中，CdSe/ZnS QD 用氨基苯硼酸（APBA）进行修饰，得到可以作为葡萄糖纳米传感器的 QD-APBA 缀合物。在纳米粒子表面上连接硼酸部分会猝灭 QD 的平均 PL 寿命。当葡萄糖与硼酸结合时，PL 会恢复并且其寿命会增强。通过 FLIM，纳米传感器成功地应用于 MDA-MB-231 细胞中葡萄糖的检测。QD 纳米粒子的长 PL 寿命使其易于与细胞自发荧光区分开来，从而提高了其传感应用的选择性。由于细胞内葡萄糖水平与癌细胞的代谢状态有关，因此所提出的纳米传感器有可能用于癌症诊断。
