Quantitative Detection of Parathyroid Hormone Using Europium Complex Doped Silica Nanoparticles

Parathyroid hormone (PTH) is a hormone that plays a critical role in bone remodeling because it regulates the calcium levels. Either higher or lower than normal range of PTH release can cause serious metabolic disorders such as hyperparathyroidism or hypoparathyroidism. Therefore, the demand of highly sensitive monitoring sensor of PTH is on the rise. However, due to its presence of small size and low concentration in serum, the monitoring of a small change of PTH level is extremely difficult. In this article, we suggested the fabrication of europium complex doped nanoparticles conjugated with PTH antibodies for the sensitive fluorescence monitoring of PTH. For the synthesis of europium complex, 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (NTA) and trioctylphosphine oxide (TOPO) are used to encapsulate europium. The amphiphilic polymer, polyvinylpyrrolidone (PVP), was applied to hydrophobic europium complex, and then silica shell was synthesized on the complex. Using the europium complex doped silica nanoparticles, we could obtain approximately 4.24-fold enhanced fluorescence in low levels of PTH in PBS, when compared to the conventional enzyme-linked immunosorbent assay (ELISA). In addition, we could obtain the sensitive PTH immunoassay in PTH spiked serum with high selectivity.

Photoluminescence of Homoleptic Lanthanide Complexes With Tris(benzotriazol-1-yl)borate

Bright photoluminescent neutral complexes having general formula [Ln(tbtz)3] (Ln = Eu, Tb; tbtz = tris(benzotriazol-1-yl)borate) were obtained by reacting K[tbtz] with EuCl3 and TbCl3. The emissions in the visible range, related to the f-f transitions of the trivalent lanthanide ions, are observable upon excitation with wavelengths shorter than 350 nm. The most intense emission bands correspond to the 5D0 → 7F4 transition at 699 nm for the europium complex and to the 5D4 → 7F5 transition at 542 nm for the terbium derivative. The luminescence is in all the cases mostly associated with the antenna-effect from the coordinated tbtz ligands. The synthetic approach was successfully extended to the preparation of the analogous yttrium and gadolinium derivatives. Tricapped trigonal prismatic geometry was attributed to the complexes on the basis of luminescence data and DFT calculations. Highly photoluminescent plastic materials were obtained by embedding small amounts of [Eu(tbtz)3] or [Tb(tbtz)3] in poly(methyl methacrylate).

Enhanced Photoluminescence of Electrodeposited Europium Complex on Bare and Terpyridine-Functionalized Porous Si Surfaces

The trivalent Eu(III) ion exhibits unique red luminescence and plays an significant role in the display industry. Herein, the amperometry electrodeposition method was employed to electrodeposit Eu(III) materials on porous Si and terpyridine-functionalized Si surfaces. The electrodeposited materials were fully characterized by scanning electron microscopy, X-ray diffraction crystallography, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Photoluminescence (PL) spectroscopy revealed that PL signals were substantially increased upon deposition on porous Si surfaces. PL signals were mainly due to direct excitation and charge-transfer-indirect excitations before and after thermal annealing, respectively. The as-electrodeposited materials were of a Eu(III) complex consisting of OH, H2O, NO3−, and CO32− groups. The complex was transformed to Eu2O3 upon thermal annealing at 700 °C. The electrodeposition on porous surfaces provide invaluable information on the fabrication of thin films for displays, as well as photoelectrodes for catalyst applications.

Electrospinning Synthesis of Fe3O4/Eu(DBM)3phen/PVP Multifunctional Microfibers and Their Structure, Luminescent and Magnetic properties

Multifunctional Fe3O4/Eu(DBM)3phen/PVP ((DBM: dibenzoylmethane, phen: 1,10-phenanthroline, PVP: polyvinyl pyrrolidone) microfibers were constructed by simple electrospinning process. The structure and morphology of the microfibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The diameters of pure PVP microfibers and the microfibers doped only with Fe3O4 nanoparticles (NPs) were uniformly distributed, with an average size of about 360 nm. When 3% Eu(DBM)3phen complex and Fe3O4 NPs were both added to the precursor for electrospinning, the microfibers became very inhomogeneous in diameter. The photoluminescent properties of pure Eu(DBM)3phen complex and composite microfibers were also studied. The characteristic emission peaks of Eu3+ appeared in the composite microfibers. The intensities of emission and excitation spectra gradually decrease with adding more Fe3O4 NPs. The unit mass of the pure europium complex in some composite microfibers gave stronger luminescence than the pure europium complex. The fluorescence lifetime of 5D0 state in the composite microfibers is longer than that of pure europium complex. Additionally, the magnetic properties of Fe3O4 NPs and the composite microfibers were investigated. Fe3O4 NPs and composite microfibers were both superparamagnetic. The saturation magnetization of the composite microfibers was smaller than that of pure Fe3O4 NPs.