摘要
Magnetic-luminescent nanocomposites have obtained a great deal of attention due to their potential applications in magnetic separation of cells, magnetic resonance imaging and luminescence imaging, and so on. Herein, a new and facile two-step synthetic strategy was developed to prepare magnetic Fe304 modified single crystalline up- conversion luminescent NaYF4： Yb3＋, Er3＋ nanocrystals using Fe304 nanoparticles as the seeds. Acting as the ＂nu- clei＂ in the reaction, the presence of Fe304 nanoparticles facilitates the formation of up-conversion NaYF4： Yb3＋, Er3＋ nanocrystals on their surfaces through heterogeneous nucleation process. The structure and properties of these multifunctional nanocrystals were characterized by transmission electron microscope （TEM）, X-ray photoelectron spectroscopy （XPS）, photo luminescence （PL） and X-ray diffraction （XRD）. The results revealed that the as-prepared multifunctional nanocrystals show dual distinct properties of up-conversion fluorescent and superpara- magnetism, which were cubic in shape and very uniform in size with an average size ranging 30m40 nm. These unique functionalities could be very attractive for biological systems, and some biological applications such as cell- labelling were also demonstrated.
Magnetic-luminescent nanocomposites have obtained a great deal of attention due to their potential applications in magnetic separation of cells, magnetic resonance imaging and luminescence imaging, and so on. Herein, a new and facile two-step synthetic strategy was developed to prepare magnetic Fe304 modified single crystalline up- conversion luminescent NaYF4： Yb3＋, Er3＋ nanocrystals using Fe304 nanoparticles as the seeds. Acting as the ＂nu- clei＂ in the reaction, the presence of Fe304 nanoparticles facilitates the formation of up-conversion NaYF4： Yb3＋, Er3＋ nanocrystals on their surfaces through heterogeneous nucleation process. The structure and properties of these multifunctional nanocrystals were characterized by transmission electron microscope （TEM）, X-ray photoelectron spectroscopy （XPS）, photo luminescence （PL） and X-ray diffraction （XRD）. The results revealed that the as-prepared multifunctional nanocrystals show dual distinct properties of up-conversion fluorescent and superpara- magnetism, which were cubic in shape and very uniform in size with an average size ranging 30m40 nm. These unique functionalities could be very attractive for biological systems, and some biological applications such as cell- labelling were also demonstrated.
基金
supported by Major Basic Research Programme of Science and Technology Commission of Shanghai Municipality （No. 10JC1403200）, Shuguang Talents Programme of Edu- cation Commission of Shanghai Municipality （No. 09SG27）, National Natural Science Foundation of China （Nos. 20973059, 91022023, 21076076）, Fundamental Research Funds for the Central Universities （No. WJ0913001）, Program for Professor of Special Appointment （Eastern Scholar） at Shanghai Institutions of Higher Learning and Program for New Century Excel- lent Talents in University （No. NCET-09-0347）.
