RESUMO
We report a biphasic system (BPS) consisting of PEGylated Tb(3+)-doped GdPO4 nanorice sensitized with Ce(3+) (PEG-NRs) and glutamic acid coated iron oxide nanoparticles (IONPs) with multifunctional capabilities. The mesoporous PEG-NRs exhibit green light luminescence properties and a high degree of aqueous stability. Their drug loading and release capacities were investigated for anti-cancer chemo doxorubicin (DOX). Their mesoporous nature and availability of plenty of negatively charged functional groups (-COO(-)) on the surface of PEG-NRs facilitate approximately 94 wt% DOX loading. In vitro studies carried out for PEG-NRs and their biphasic integrated system with iron oxide using HeLa and MCF-7 cell lines demonstrated their cell killing efficacy. The green luminescence observed under confocal laser scanning microscopy (CLSM) confirms the cellular uptake of PEG-NRs by HeLa cell lines and their accumulation in the cytoplasm. Approximately 50-55% of HeLa and MCF-7 cell death was observed after 24 h of incubation with DOX loaded BPS (2 mg IONPs and 0.25 mg PEG-NRs + DOX), which further increased to about 90% when exposed to an AC magnetic field (ACMF) for 25 min. Our findings demonstrate that the therapeutic efficacy of BPS loaded with DOX could be a powerful multimodal system for imaging and synergistic chemo-thermal cancer therapy.
Assuntos
Cério/química , Compostos Férricos/química , Gadolínio/química , Nanopartículas Metálicas/química , Compostos Organometálicos/química , Fosfatos/química , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Portadores de Fármacos , Humanos , Luminescência , Compostos Organometálicos/farmacologiaRESUMO
Re-dispersible Tb(3+) doped LaPO(4) nanorods have been prepared using ethylene glycol (EG) as a capping agent as well as reaction medium at a relatively low temperature of 150 °C. The X-ray diffraction study reveals that all the doped samples are well crystalline with a monoclinic structure of the LaPO(4) phase. The luminescence intensity of (5)D(4)â(7)F(5) transition at 543 nm (green) is more prominent than that of (5)D(4)â(7)F(6) transition at 487 nm (blue) for all the samples. This is related to the polarizing effect from [PO(4)](3-) to the Tb(3+) site. Concentration dependent luminescence study shows that the luminescence intensity of Tb(3+) increases up to 10 at.% and decreases above this. This is due to the concentration quenching effect arising from cross relaxation among Tb(3+)-Tb(3+) ions. The results show that nanoparticles prepared in EG medium gives an enhanced luminescence compared to that prepared in water. This is attributed to the multiphonon relaxation effect from O-H groups surrounding over nanoparticles as well as the extent of increase of agglomeration among particles for samples prepared in water. Significant enhancement in the emission of Tb(3+) is also observed when Ce(3+) is used as the sensitizer in LaPO(4):Tb(3+)nanorods. The optimum concentration of Ce(3+) for maximum luminescence is found to be 7 at.% in Ce(3+) sensitized LaPO(4):Tb(3+) (5 at.%). Based on the energy transfer process from Ce(3+) to Tb(3+), the luminescence of Tb(3+) can be switched OFF and ON by performing oxidation and reduction of Ce(3+)âCe(4+) using KMnO(4) and ascorbic acid, respectively. The samples are re-dispersible in water, methanol and can be incorporated into polyvinyl alcohol (PVA) films. They show a dark green emission under ultraviolet radiation.