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Phototherapy Using Nanomaterials
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
A. N. Resmi, V. Nair Resmi, C. R. Rekha, V. Nair Lakshmi, Shaiju S. Nazeer, Ramapurath S. Jayasree
Scintillation nanoparticles, such as BaFBr: Eu2+, Mn2+, and LaF3:Tb3+, will emit luminescence for activating the photosensitizers following exposure to ionizing irradiation. This results in the production of 1O2 which enhances the destruction of cancer cells. The efficiency of LaF3:Tb3+-meso-tetra (4-carboxyphenyl) porphine (MTCP) nanoparticle conjugated as photodynamic agents following X-ray irradiation was investigated [211]. They described the effective energy transfer and 1O2 generation mechanism upon initiation by X-rays at low dose. These scintillation nanoparticles can be possibly utilized as a promising deep cancer treatment modality. Another study described SLPDT against ovarian cancer and they synthesized zinc oxide (ZnO) nanoparticles conjugated to porphyrin (ZnO-MTAP). The photoactivation of ZnO-MTAP conjugates led to ROS release, which could be effectively targeted to tumor cells [212]. In the case of persistent-luminescence nanoparticles, the luminescence continues even after the excitation source is ceased. This long decay lifetime will decrease the ionization dose and prolonged photosensitizer excitation required for cancer treatment. The application of these nanoparticles in biological systems needs to be further explored.
A new insight into the mechanism of persistent luminescence phosphors SrS: Eu2+, Pr3+
Published in Radiation Effects and Defects in Solids, 2023
Chao Xu, Shenao Yu, Linxing Shi, Yuanyuan Zhang, Qile Li
Persistent luminescence is an optical phenomenon, i.e. a material can glow lasting for hours after the stoppage of the excitation (1,2). Persistent luminescence phosphors have versatile applications, such as light illumination (3–7), optical storage (8–10), photostimulated luminescence dosimeters (3,11), near-infrared to visible converters (12,13), vivo bio-imaging (14,15), and anti-counterfeiting technology et al (16). The green persistent phosphors SrAl2O4: Eu2+, Dy3+ and blue ones CaAl2O4: Eu2+, Nd3+, have already been commercialized (17,18). Otherwise, the performances of red persistent phosphors are unsatisfactory (3,19,20). Therefore, the red persistent materials with excellent performances have attracted much attention and have been deeply studied. Many persistent phosphors have been reported, including sulfide, oxysulfide, titanate, silicate, and aluminate, et al. (2,11,21). Alkaline-earth sulfides (Ca, Sr, Mg)S have attracted much attention in the luminescent display industry resulting from their high luminous efficiency (3). They were also investigated as an important persistent luminescence materials host, which could be modulated to glow with different wavebands by doping proper dopants (3,22). The SrS: Eu2+ phosphor is a potential candidate for being an excellent red persistent luminescence material, in which a great number of intrinsic defects are generated resulting from its soft base-hard acid character (20). Especially, these phosphors encapsulated with an oxide coating present better anti-moisture properties, which improves their applicability (23).