title: Multimodal bioimaging using rare earth doped Gd2O2S: Yb/Er phosphor with upconversion luminescence and magnetic resonance properties.
abstract: While infrared upconversion imaging using halide nanoparticles are so common the search for a very efficient halide free upconverting phosphors is still lacking. In this article we report Gd2O2S:Yb/Er,YbHo,YbTm systems as a very efficient alternative phosphors that show upconversion efficiency comparable or even higher than existing halide phosphors. While the majority of rare earth dopants provide the necessary features for optical imaging, the paramagnetic Gd ion also contributes to the magnetic imaging,thereby resulting in a system with bimodal imaging features. Results from imaging of the nanoparticles together with aggregates of cultured cells have suggested that imaging of the particles in living animals may be possible.In vitrotests revealed no signficant toxicity because no cell death was observed when the nanoparticles were in the presence of growing cells in culture. Measurement of the magnetization of the phosphor shows that the particles are strongly magnetic, thus making them suitable as an MRI agent.
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249.
authors.forename: G
authors.initials: G
authors.lastname: Ajithkumar
authors.affiliation: Department of Physiology and Barshop Institute,University of Texas Health Science Center at San Antonio, San Antonio, TX 78245.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Yoo
authors.affiliation: Department of Physiology and Barshop Institute,University of Texas Health Science Center at San Antonio, San Antonio, TX 78245.
authors.forename: Dara E
authors.initials: DE
authors.lastname: Goral
authors.affiliation: Department of Physiology and Barshop Institute,University of Texas Health Science Center at San Antonio, San Antonio, TX 78245.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hornsby
authors.affiliation: Research Imaging Institute, Barshop Institute and Department of Cellular & Structural Biology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229.
authors.forename: Ai-Ling
authors.initials: AL
authors.lastname: Lin
authors.affiliation: UM-DAE Centre for Excellence in Basic Sciences, Health Centre Bldg, University of Mumbai, Kalina Campus, Mumbai 400098.
authors.forename: Uma
authors.initials: U
authors.lastname: Ladiwala
authors.affiliation: Department of Materials Science and Engineering,Northwestern University,2220 Campus Drive,Evanston, IL 60208-3108.
authors.forename: Vinayak P
authors.initials: VP
authors.lastname: Dravid
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249.
authors.forename: Dhiraj K
authors.initials: DK
authors.lastname: Sardar