478123 High-Throughput Synthesis of Lanthanide-Doped NaYF4 Upconverting Nanoparticles

Monday, November 14, 2016
Grand Ballroom B (Hilton San Francisco Union Square)
Deepak Subramanian1, Thomas Bischof2 and Emory Chan2, (1)The University of Texas at Austin, Austin, TX, (2)Molecular Foundry, Lawrence Berkeley National Laboratory

Biological imaging, and in particular the imaging of cells and cancerous tumors in vivo, is important in order to monitor the growth and progression of cancers. However, biological imaging of tumors in vivo is difficult because of the impermeability of light into tissue, while current methods such as the use of fluorescent dyes or quantum dots for imaging purposes have issues such as high background autofluorescence and relatively low photostability. Upconverting nanoparticles, which are nanoparticles that exhibit the property of upconversion and can therefore convert lower-energy light into higher-energy light through an anti-Stokes energy transfer mechanism, have potential uses in biological imaging because of both their conversion of near-infrared (NIR) light into visible light within the skin (which allows them to harness the superior penetration of NIR light into tissue) and their ability to mitigate the issues presented by current biological imaging techniques. A promising group of upconverting nanoparticles are NaYF4 nanoparticles (specifically β-phase NaYF4 nanoparticles), which have very strong emission and absorption spectra and can be easily doped with lanthanide ions that provide tunable emission spectra based on composition and concentration of the lanthanide ions. Lanthanide-doped β-phase NaYF4 upconverting nanoparticles were synthesized using both conventional thermolytic synthesis procedures and high-throughput automated synthesis procedures. In order to determine the optimal reaction conditions to produce monodisperse nanoparticles with uniform shape and phase, parameters such as surfactant concentration, reaction temperature, temperature ramp rate, solvent concentration, and sodium to rare earth ratio were modified to elucidate their effects on the physical and optical properties of the synthesized nanoparticles, using the unique capabilities of the Workstation for Automated Nanomaterials Discovery and Analysis (WANDA). After variation of these parameters and determination of the effect of these parameters on the size, shape, and phase of synthesized nanoparticles, we were able to determine a robust set of conditions that allow for synthesis of lanthanide-doped β-phase NaYF4 nanoparticles with sizes ranging from 100 nm to 350 nm, and can produce both nanorods and hexagonal prisms.

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