Seminar INFLPR, Joi, 25 Ianuarie 2018, ora 12:00, Laborator FPFN, Daniel Avram: "Nanosisteme dopate cu lantanide pentru aplicatii de imagistica cu raze X”

INFLPR Seminar

Thursday, 25 January 2018, 12:00 pm

Plasma Physics and Nuclear Fusion Laboratory, INCDFM, Seminar Room

Contract number: 4N/2016

Project: PN 16 47 01 03, "Multidisciplinary studies with lasers, plasma and radiations in public priority domains (environment and healthcare)"

Phase no. 28: "Lanthanide-doped nanosystems for X ray imaging applications”

Deadline: 20.12.2017

Responsible: Dr. Carmen Tiseanu

Lecturer: Daniel Avram

Abstract: This report contains our studies on biologically relevant luminescence of lanthanide doped nanoparticles aiming at applications in theranostics and temperature sensing. Near-infrared luminescence around 980 and 1500 nm was obtained under X-ray and optical excitation in several lanthanide doped oxide hosts, such as CeO₂, Y₂O₃ and Lu₂O₃ and Gd₂O₂S. We have also obtained “quasi” persistent luminescence of Eu and Sm in SnO₂ with emission lifetimes of the order of tens of ms. We present also first report on the luminescence thermometry properties of Er, Yb doped Gd₂O₂S microparticles under near infrared up-conversion excitation around 980 and 1500 nm measured in the 280 to 800 K interval. The thermometry properties are assessed using both cw and ns pulsed excitation as well as tuning the excitation wavelength across Yb and Er absorption profiles. Although for 1500 nm excitation, the temperature sensitivity is lower (~0.008 % K-1), our data represent a first step for opening the thermometry applications of this material at two biologically relevant near-infrared excitation ranges. All nanoparticles have been extensively optimized by using multiple strategies: co-doping with monovalent ions (Li), modifying the concentration of the dopant activator (Er: 0.3 ÷ 7%), use of a sensitizer co-dopant (20% Yb) and varying the anneal temperature. We have also shown that the emission enhancement by Li addition in Ln, Li−Y₂O₃ is due to improved crystallization and not to local structure distortion. Our results have been published in four ISI journals: (1) J. Phys. Chem. C. (2017) 121 (26), 14274–14284, (2) Sci. Rep. (2017) 7 (1) 9598, (3) Methods Appl. Fluoresc. (https://doi.org/10.1088/2050-6120/aa9ef9) and (4) and J. Alloys Compd. (2017) 711, 627-636.