Encapsulation of Magnetic and Fluorescent Nanoparticles in Emulsion Droplets

Abstract

Oils containing both fluorescent semiconductor and magnetic oxide nanoparticles are used to produce oil in water emulsions. This technique produces oil droplets with homogeneous fluorescence and high magnetic nanoparticle concentrations. The optical properties of the oil droplets are studied as a function of the droplet sizes for various concentrations of fluorescent and magnetic nanoparticles. For all concentrations tested, we find a linear variation of the droplet fluorescent intensity as a function of the droplet volume. For a given size and a given quantum dot (QD) concentration, the droplet fluorescence intensity drops sharply as a function of the magnetic nanoparticle concentration. We show that this decrease is due mainly to the strong absorption cross section of the magnetic nanoparticles and to a lesser extent to the dynamic and static quenching of the QD fluorescence. The role of the iron oxide nanoparticle localization in the droplet (surface versus volume) is also discussed.

Photoswitchable Fluorescent Nanoparticles: Preparation, Properties and Applications

“…Evidently, the fluorescence quenching role of iron oxide nanoparticles in such system was significantly depressed, probably due to the special core-shell geometric arrangement with iron nanoparticles confined in the core while the diarylethene moiety in the shell. [121] Obviously, such unique combination of superparamagnetic feature and photoswitchable fluorescence in a single nanoparticle enables potential new applications in biological detection, separation, and imaging. …”

Fabrication of Silica Nanoparticles with Both Efficient Fluorescence and Strong Magnetization and Exploration of Their Biological Applications

“…[ 1 ] Little effort has, however, been devoted to the development of such nanoparticles, in comparison to the great wealth of the studies on the particles with a single attribute of either fl uorescence or magnetization. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Silica and polymer are favorable host materials for the inclusion of chromophores and nanoclusters because of their optical transparence and biological compatibility. The encapsulation can protect the dye molecules from external perturbations such as oxygen and ions dissolved in solutions.…”

Micellar Hybrid Nanoparticles for Simultaneous Magnetofluorescent Imaging and Drug Delivery

“…[13,14] Additionally, the proximity of MN and other QD in the MHN is likely to cause fluorescence quenching through non-radiative energy or charge transfer. [10,25] Despite the quenching, fluorescence is intense enough to allow detection of MHN at subnanomolar QD concentrations. These inorganic QD-containing hybrid systems can be excited and observed in the NIR spectral region with high photostability, [26,27] providing significant advantages over MN labeled with organic fluorophores.…”