Research On Morphology And Fluorescence Of Tb/Eu Doped Nano-Hydroxyapatite

Hydroxyapatite(HA) is the principal inorganic component of human and animal hard tissues (such as bones and teeth) with an excellent biocompatibility, bioactivity, biodegradability and non-immunogenicity. In recent years, inorganic gene vectors have become a hot research gene vector. Nano-HA particles as gene vectors have been paid more attention due to its excellent biomedical properties. However, the transfection mechanism of HA gene vectors was still unknown. In order to investigate the state of HA gene vectors after entering into cells, it was crucial to prepare luminescent HA phosphors. In this paper, the terbium/europium-doped nano-HA powders with strong fluorescence was prepared by hydrothermal synthesis and its crystal structure,morphology and fluorescent properties are discussed under the conditions of the amount of terbium/europium doping,pH value and hydrothermal time. The main results are summarized as followed:(1) With the doping concentraction of Tb3+ increased from 1mol% to 5mol%, the morphology of nano-Tb:HA particles changes from rods to irregular rods and needle, fluorescence intensity is significantly enhanced. Excited by ultraviolet ray at 272 nm, there are four emission peaks of 5D4-7F6 at 488 nm,5D4-7F5 at 543 nm,5D4-7F4 at 583 nm and 5D4-7F3 at 619 nm of Tb3+, which 5D4-7F5 transition is the main emission peak.(2) With pH values increased from 6.5 to 10.0, The morphology of nano-Tb:HA particles changes from rod particles to equiaxed particles and needle-like and irregular particles, and the fluorescence intensity tends to increase correspondingly.(3) With reaction time prolonged from 3h to 24h, The morphology of nano-Tb:HA particles are mainly short rod-like and needle-like, the aspect ratio of particles tends to decrease. Meanwhile, the fluorescence intensity increase correspondingly with the actual doping concentration of Tb3+ increased from 2.88mol% to 2.97mol%.(4) With the doping concentraction of Eu3+ increased from 1mol% to 7.5mol%, the morphology of nano-Eu:HA particles changes from short rods to irregular short rods and needle, and the fluorescence intensity of nano-Eu:HA particles is enhanced remarkablely. There are three characteristic excitation peaks of 7F0-5D4 in 361 nm,7F0-5G2 in 381 nm and 7F0-5L6 in 394nm. Excited by ultraviolet ray in 394 nm, there are two characteristic emission peaks of 5D0-7F1 in 588nm and 5D0-7F2 in 613nm, and 613 nm is the maximum emission peak.(5) With pH values increased from 6.5 to 10.0, the morphology of nano-Eu:HA particles changes from rod particles to equiaxed particles. The fluorescence intensity also tends to weakly lower correspondingly with the doping concentraction of Tb3+ decreasing.(6) With reaction time prolonged from 3 h to 24 h, the morphology of nano-Eu:HA particles is mainly rod-like and equiaxed grain, and the aspect ratio of particles tends to decrease. The fluorescence intensity of nano-Eu:HA particles tends to lower correspondingly with the actual doping concentration of Eu3+ decreasing...