Yong’an Tang,Jun Hu,Ahmed H. Elmenoufy,Xiangliang Yang
Photodynamic therapy (PDT) for deep-seated tumor is largely impeded by the limited penetration depth of excitation light in tissue. X-ray is considered as an ideal energy source to activate photosensitizers (PSs) located deep within the body with the assistance of scintillating nanoparticles (ScNPs). However, the efficacy under this concept is not satisfying due to the low scintillating luminescence and weak energy transfer from ScNPs to PSs. Here, mesoporous LaF3:Tb ScNPs were successfully synthesized by a facile hydrothermal process to act as PS carriers and X-ray energy transducers, owing to their good ionizing radiation stopping power and high luminescence efficiency. The formation mechanism of porous structure was elucidated in detail with classical crystallization theory. After a systematic investigation, LaF3:Tb ScNPs with optimized scintillating luminescence were obtained for loading Rose Bengal (RB) to establish an efficient FRET system, owing to their excellent spectral match. The FRET efficiency between ScNPs and RB was calculated to be as high as 85%. Under irradiation, enhanced 1O2 generation induced by LaF3:Tb-RB nanocomposites via FRET process was detected. This LaF3:Tb-RB FRET system shows great potential to be applied in X-ray stimulated PDT for deep-seated tumors in the future.
In this work, a facile method for the preparation of dual-emission lanthanide nanoparticles (NPs) was developed. Tb 3+ -doped LaF 3 NPs coated with 2,6-pyridinedicarboxylic acid (DPA) and Eu 3+ , namely LaF 3 :Tb@DPA-Eu NPs, could produce characteristic emissions of Tb 3+ and Eu 3+ under 272 nm excitation, which originated from the absorption of DPA. The LaF 3 :Tb@DPA-Eu NPs with tunable emission peaks and color could be synthesized by changing the concentration of Eu 3+ . Additionally, the obtained NPs were comprehensively characterized by various analytical methods. Transmission electron microscopy (TEM) images showed that the average size of the NPs was ~15 nm. Moreover, X-ray diffraction (XRD) analysis revealed that the products were single-phase LaF 3 , while the doped Tb 3+ entered the LaF 3 lattice to occupy the La 3+ sites. Owing to their excellent water solubility and good optical properties , the LaF 3 :Tb@DPA-Eu NPs were used as a fluorescence probe for the detection of marbofloxacin (MAR) based on the fluorescence quench. Notably, an effective ratiometric fluorescence method was established. The approach exhibited good sensitivity and selectivity with a linear range of 0.10 ~ 10.0 μM and detection limit of 85 nM. It was successfully employed for the determination of MAR in milk samples with recoveries of 98.1%–106%. Thus, the fluorescence method based on the LaF 3 :Tb@DPA-Eu NPs developed herein provides a convenient and fast platform for the detection of MAR.
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