XRD patterns of NaYbF4, 2%Tm nanocrystals fabricated under diffrent conditions: (a) 30mL BmFimPF6. (b) 30 mL BmimPF6 and 50mol% Gd(oleate)3. (c) 30 mL BmimPF6, 30mol% Gd(oleate)3 and excess sodium oleate. (d) 30 mL BmFimPF6 and 30mol% Gd(oleate)3. (e) 30 mL BmimPF6, 25mol% Gd(oleate)3. (f) 30 mL BmimPF6, 25mol% Gd(oleate)3 and excess sodium oleate. The peaks marked with a cubic box refer to cubic-phase NaYbF4.
The formation process of NaREF4 is that the C17H33COO- bonded with RE3+ is gradually replaced by PF6-, then when the whole system reaches a certain temperature, F- anions are released from the cleavage of P-F bond to react with RE3+ ions. As we known, C17H33COO- has a strong coordination capacity with RE3+ ions, we believe the increasing volume of sodium oleate will make the competition between PF- anions and C17H33COO- much fiercer which slows down the formation process of NaREF4 and facilitate the anisotropic growth and lead to the formation of hexagonal structure. It is also possible because the increasing volume of Na3+ ions makes it easier to occupy the sites in the cationic sublattice. Scheme 1 (Figure ) shows the process of the formation of hexagonal RE fluoride nanocrystals in an OA/IL two-phase synthesis system.
Generalized Synthesis of Metal Oxide Nanosheets and …
To evaluate the cytotoxicity of UCNP@SiO2-NH2 and UCNP-FA nanocrystals, we conducted CCK assays on human gastric cancer cell line MGC-803 cells, at 37 oC for 24h. The viability of untreated cells was assumed to be 100%. As shown in Figure (2), cell viabilities of MGC-803 cells incubated with different doses of UCNP@SiO2-NH2for 24h were over 80%, As it shows in Figure (2), the cell viabilities of MGC-803 cells incubated with different concentration of UCNP-FA decreased comparing to UCNP@SiO2-NH2 treated cells, but most of the samples were over 80% viability, which fully suggests that prepared UCNPs and UCNP-FA have low cytotoxicity, and may be ideal candidates for further biological applications.
Shape-controlled synthesis of palladium nanocrystals: …
In vitro cytotoxicity of prepared UCNPs to human gastric cancer cell line MGC-803 cells was measured by using CCK-8 kit. The human gastric cancer cell line MGC803 cells were cultivated in Roswell Park Memorial Institute medium (RPMI) 1640 (Gibco, Invitrogen Corp., Carlsbad, CA) medium supplemented with 10% fetal bovine serum (FBS) and 1% penicillin in 96-well plate 5% CO2, 37 oC for 24 h. The density of cells in a 96-well plates is 4×103 cells /well (the 36 peripheral wells were filled with PBS, the remaining was control group). On the second day, different volume of UCNP@SiO2-NH2 nanocrystals before and after FA conjugation were dissolved in culture medium and the final concentration was 50, 100, 200, 400, 800 μg/mL. Thereafter, the medium was removed and cells were washed with PBS for two times. Cell viability was evaluated by CCK-8 kit, the optical absorbance of the solution was measured at 450 nm with 96-well microplate reader (Perkine Elmer). Results are calculated as percentages relative to control cells. Data are mean ±SD from three independent experiments.
PbSe Nanocrystals (NCs) -from synthesis to applications-
The folic acid conjugated UCNP nanocrystals were prepared by conjugating the amine-functionalized UCNP@SiO2-NH2 (NaYbF4: 25 mol% Gd, 2 mol% Tm) with activated folic acid(FA). In brief, FA (120 mg, 2.72×10−4mol) was dissolved in 25mL anhydrous dimethylsulfoxide (DMSO). EDC and NHS (molar ratio of FA/EDC/NHS=1:1:2.5) were added, and the mixture was stirred gently at room temperature for 1 h. UCNP@SiO2-NH2 nanocrystals (30mg) dissolved in DMSO (20 mL) were added to the activated FA solution, and the mixture was stirred gently for 3h at room temperature. The resultant precipitates were separated by centrifugation at 12000 rpm for 15 min and subsequently washed 3 times with PBS (pH 7.4). The powder was then dried under vacuum.