Multifunctional Fe 3 O 4 /Eu(DBM) 3 phen/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 Fe 3 O 4 nanoparticles (NPs) were uniformly distributed, with an average diameter of about 360 nm. When 3% Eu(DBM) 3 phen complex and Fe 3 O 4 NPs were both added to the precursor for electrospinning, the microfibers became very inhomogeneous in diameter. The photoluminescent properties of pure Eu(DBM) 3 phen complex and composite microfibers were also studied. The characteristic emission peaks of Eu 3+ appeared in the composite microfibers. The intensities of emission and excitation spectra gradually decrease with adding more Fe 3 O 4 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 5 D 0 state in the composite microfibers is longer than that of pure europium complex. Additionally, the magnetic properties of Fe 3 O 4 NPs and the composite microfibers were investigated. The saturation magnetization of the composite microfibers was smaller than that of pure Fe 3 O 4 NPs.
Sphere-shape Eu(DBM) 3 Phen@SiO 2 nanoparticles were fabricated by employing a modified alkaline catalyzed hydrolysis and precipitation method. The silica coated on the particles surface was obtained by means of hydrolysis and condensation of tetraethyl orthosilicate (TEOS). In this study, the particles morphology was analyzed by scanning electron microscopy (SEM) and the surface composition of samples was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). It is confirmed that the SiO 2 shell has been coated on the rare earth complexes successfully. Moreover, the near-infrared photoluminescence emission analysis on the nanoparticles showed that the SiO 2 shell would increase the luminescence intensity of Eu(DBM) 3 Phen. This is primarily due to the reason that SiO 2 shell with chemical inertness can effectively reduce the ion Eu 3+ non-radiation transition probabilities, as well as the probability of rare earth luminescence quenching caused by the external medium.
Tao Liao,Fang Yuan,Chuan Shi,Chuan-Xin He,Zigang Li
Procalcitonin (PCT) is a potentially specific early marker of bloodstream infection and sepsis. In this work, we report, for the first time, the development of a fluorescence-based immunochromatographic strip test (IST) which employs Eu(DBM)3phen-containing nanoparticles as reporters for the detection of PCT in human serum. Experimental results demonstrate that the developed IST has an excellent ability for rapid (15 min), sensitive (0.05 ng mL−1) and quantitative analysis of PCT, and the assay results are comparable to which of the conventional enzyme-linked immunosorbent assay (ELISA). These results suggest that the developed assay could be utilized for point-of-care detection of PCT.
Mou Yongren,Kang Ming,Wang Feng,Liu Min,Chen Kexu,Sun Rong
Abstract Monodisperse core-shell structured SiO 2 @SiO 2 :Eu(DBM) 3 phen microspheres, as a new kind of fluorescent particles, were fabricated by a seeded growth method in the presence of surfactant CTAB (DBM = dibenzoylmethane, phen = 1,10-phenanthroline, CTAB = cetyltrimethyl ammonium bromide). In this way, a thin mesoporous silica shell doped with Eu(DBM) 3 phen was grown on the prepared monodisperse silica colloids. The structures of the as-prepared phosphors were characterized by means of X-ray diffraction, Fourier transform infrared spectrum, thermal gravimetric analysis–differential scanning calorimetry, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, nitrogen adsorption-desorption techniques, and photoluminescence spectra. The experimental results show that the microshpere has a typical core-shell structure with a diameter of about 370 nm, consisting of the silica colloids core with about 340 nm in diameter and mesoporous silica shell doped with europium complexes with an average thickness of about 15 nm. The as-obtained core-shell microspheres exhibit a strong red emission peak originating from electric-dipole transition 5 D 0 → 7 F 2 (610 nm) of Eu 3+ ions under the excitation of 405 nm. Additionally, the photoluminescence intensity increases with the increasing of europium complexes concentration in mesoporous silica shell, and concentration quenching occurs when europium complexes concentration exceeds 7.0 mol%. The prepared microspheres may present potential applications in the fields of optoelectronic devices, bio-imaging, medical diagnosis, and the packing structural functional composites. Graphical Abstract Monodisperse core-shell structured SiO 2 @SiO 2 : Eu(DBM) 3 phen microspheres with high lumious performance were fabricated by a seeded growth method by means of surfactant CTAB.
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