title: Synthesis of NaYF(4):Yb/Er/Gd up-conversion luminescent nanoparticles and luminescence resonance energy transfer-based protein detection.
abstract: High-quality NaYF₄:Yb/Er/Gd up-conversion nanoparticles (UCNPs) were first synthesized by a solvothermal method using rare earth stearate, sodium fluoride, ethanol, water, and oleic acid as precursors. Doped Gd³⁺ ions can promote the transition of NaYF₄ from cubic to hexagonal phase, shorten the reaction time, and reduce the reaction temperature without reducing the luminescence intensity of NaYF₄:Yb/Er UCNPs. X-ray diffraction, infrared spectroscopy, transmission electron microscopy, and luminescence spectroscopy were applied to characterize the UCNPs. The nanoparticles exhibited small size and excellent green up-conversion photoluminescence, making them suitable for biological applications. After the surfaces of NaYF₄:Yb/Er/Gd UCNPs were modified with amino groups through the Stöber method, they could be brought close enough to the analytically important protein called R-phycoerythrin (R-PE) bearing multiple carboxyl groups so that energy transfer could occur. A luminescence resonance energy transfer (LRET) system was developed using NaYF₄:Yb/Er/Gd UCNPs as an energy donor and R-PE as an energy acceptor. As a result, a detection limit of R-PE of 0.5 μg/ml was achieved by the LRET system with a relative standard deviation of 2.0%. Although this approach was first used successfully to detect R-PE, it can also be extended to the detection of other biological molecules.
authors.affiliation: Department of Chemistry, Northeastern University, Shenyang 110819, People's Republic of China.
authors.forename: Jingpu
authors.initials: J
authors.lastname: Zhang
authors.forename: Congcong
authors.initials: C
authors.lastname: Mi
authors.forename: Hongyan
authors.initials: H
authors.lastname: Wu
authors.forename: Huaiqing
authors.initials: H
authors.lastname: Huang
authors.forename: Chuanbin
authors.initials: C
authors.lastname: Mao
authors.forename: Shukun
authors.initials: S
authors.lastname: Xu
mesh_terms: D004735:Energy Transfer; D005459:Fluorides / Q000737:chemistry*; D049449:Luminescence; D008674:Metals, Rare Earth / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010799:Phycoerythrin / Q000032:analysis*; D015019:Yttrium / Q000737:chemistry*
chemical_list: D008674:Metals, Rare Earth; C525362:sodium yttriumtetrafluoride; D010799:Phycoerythrin; D015019:Yttrium; D005459:Fluorides