Hydrothermal synthesis of hydrophilic NaYF4:Yb,Er nanoparticles with bright upconversion luminescence as biological label

Fabrication of NaYF4:Yb,Er Nanoprobes for Cell Imaging Directly by Using the Method of Hydrion Rivalry Aided by Ultrasonic

“…The advantages of surface functionalization of these NPs are not only to render them reasonably water-soluble and biocompatible but also to provide active sites for subsequent coupling with biological or chemical moieties [ 34 – 41 ]. So far, many attempts have been made to transform the oil-soluble OA-capped UCNPs into water-soluble, such as polymer capping [ 42 , 43 ], surface silanization [ 44 ], OA-capped NaYF 4 :Yb,Er NP coating by hydrophilic group [ 45 , 46 ], ligand exchange [ 47 ], ligand oxidation [ 48 – 50 ], hydrochloric acid [ 16 ], and layer-by-layer method [ 51 ]. Unfortunately, all of the post-treatments are time-consuming and may lead to aggregation; furthermore, the surface modified UCNPs always have bigger size than that of before.…”

Exploring the Phase‐Selective, Green, Hydrothermal Synthesis of Upconverting Doped Sodium Yttrium Fluoride: Effects of Temperature, Time, and Precursors

“…[9] In general, reports found in the literature for the hydrothermal synthesis of sodium yttrium fluoride alwaysr equired temperatures of 180 8Co ra bove [10] and/or additives such as polyethylene glycol or imines. [8] To the best of our knowledge, this is the first time asynthetic approachisreportedu pon whereby NaYF 4 is obtained at 150 8Cins urfactant-free conditions. Apart from hydrothermal synthesis, thermald ecomposition is another common approach employed to synthesize doped NaYF 4 :s uch syntheses are usually performed with rare earth trifluoroacetate precursors in noncoordinating andhigh boiling solvents such as octadecene or oleylamine.…”

“…For hexagonal NaYF 4 ,c rystals, prisms, disks, tubes, rods, and octahedral shapes were obtained, depending on the reactionc onditions, such as the fluoride source,t he pH, and organic additives. [8] As an example, Wang et al carriedo ut several hydrothermal syntheses at 240 8Cc hangingt he molar ratio between the reactants (NaF and lanthanide oxides), yet were able to obtain cubic nanoparticles, mixtures of cubic and hexagonal nanoparticles, and hexagonal nanorods for F/Ln ratios of 5, 10, and 12, respectively. [9] Further investigations concerning the role of the solvent evidenced that, in syntheses with equal reactant molar ratios, water as as olventl ed to cubic phases, whereas ethanol (and therefore implying as witch to solvothermals ynthesis) to hexagonal ones.…”

<p>Breakthroughs in medicine and bioimaging with up-conversion nanoparticles</p>

“…The synthesis procedure can be relatively smoother than thermal decomposition in terms of temperature (130–240°C) and pressure. Nevertheless, the smoother synthesizing process suffers from a major drawback which is long reaction time depending on crystal growth and thermodynamic process 111,112. In this method, unlike the thermal decomposition that mainly occurs in organic solvents, water-based media can be applied, and this moderate system allows some biocompatible chelating ligands such as sodium citrate and ethylene diamine tetra acetate (EDTA) cover the nanocrystals instead of long chain non-biocompatible organic ligands 113,114.…”