Ferrera-González Juan, Francés-Soriano Laura, Estébanez Nestor, Navarro-Raga Enrique, González-Béjar María, Pérez-Prieto Julia
Instituto de Ciencia Molecular (ICMol), Departamento de Química Orgánica, University of Valencia, C/Catedrático José Beltrán, 2, Paterna, Valencia 46980, Spain.
Servicio Central de Soporte a la Investigación Experimental (SCSIE). University of Valencia, Burjassot, Valencia 46100, Spain.
Nanoscale. 2021 Jun 14;13(22):10067-10080. doi: 10.1039/d1nr00389e. Epub 2021 May 27.
Photophysical characterization of upconversion nanoparticles (UCNPs) and nanohybrids (UCNHs) is more challenging than that of down-conversion nanomaterials. Moreover, it is still difficult to gain knowledge about the homogeneity of the sample and colocalization of emissive chromophores and nanoparticles in nanohybrids. Near infrared laser scanning microscopy (NIR-LSM) is a well-known and useful imaging technique, which enables excitation in the NIR region and has been extensively applied to optical fluorescence imaging of organic fluorophores and nanomaterials, such as quantum dots, which exhibit a short-lived emission. NIR-LSM has recently been used to determine the empirical emission lifetime of UCNPs, thus extending its application range to nanomaterials with a long lifetime emission. Here, we review our previous findings and include new measurements and samples to fully address the potential of this technique. NIR-LSM has proved to be extraordinarily useful not only for photophysical characterization of UCNHs consisting of UCNPs capped with a fluorophore to easily visualize the occurrence of the resonance energy transfer process between the UCNH constituents and their homogeneity, but also to assess the colocalization of the fluorophore and the UCNP in the UCNH; all this information can be acquired on the micro-/nano-meter scale by just taking one image.
上转换纳米颗粒（UCNPs）和纳米杂化物（UCNHs）的光物理表征比下转换纳米材料更具挑战性。此外，了解纳米杂化物中样品的均匀性以及发光发色团与纳米颗粒的共定位仍然很困难。近红外激光扫描显微镜（NIR-LSM）是一种著名且有用的成像技术，它能够在近红外区域进行激发，并且已广泛应用于有机荧光团和纳米材料（如量子点，其发射寿命较短）的光学荧光成像。NIR-LSM最近已被用于确定UCNPs的经验发射寿命，从而将其应用范围扩展到具有长寿命发射的纳米材料。在这里，我们回顾我们之前的发现，并纳入新的测量结果和样品，以充分探讨该技术的潜力。事实证明，NIR-LSM不仅对于由包覆有荧光团的UCNPs组成的UCNHs的光物理表征非常有用，从而能够轻松可视化UCNH成分之间共振能量转移过程的发生及其均匀性，而且还能评估荧光团与UCNP在UCNH中的共定位；仅通过拍摄一张图像，就可以在微米/纳米尺度上获取所有这些信息。
