Covering the optical spectrum through collective rare-earth doping of NaGdF4 nanoparticles: 806 and 980 nm excitation routes

• Published in: Physical chemistry chemical physics : PCCP Vol. 19; no. 19; pp. 11825 - 11834
• Main Authors: Skripka, A, Marin, R, Benayas, A, Canton, P, Hemmer, E, Vetrone, F
• Format: Journal Article
• Language: English
• Published: 2017
• ISSN: 1463-9084
• DOI: 10.1039/c7cp01167a

Today, at the frontier of biomedical research, the need has been clearly established for integrating disease detection and therapeutic function in one single theranostic system. Light-emitting nanoparticles are being intensively investigated to fulfil this demand, by continuously developing nanoparticle systems simultaneously emitting in both the UV/visible (light-triggered release and activation of drugs) and the near-infrared (imaging and tracking) spectral regions. In this work, rare-earth (RE) doped nanoparticles (RENPs) were synthesized via a thermal decomposition process and spectroscopically investigated as potential candidates as all-in-one optical imaging, diagnostic and therapeutic agents. These core/shell/shell nanoparticles (NaGdF4:Er3+,Ho3+,Yb3+/NaGdF4:Nd3+,Yb3+/NaGdF4) are optically excited by heating-free 806 nm light that, aside from minimizing the local thermal load, also allows to obtain a deeper sub-tissue penetration with respect to the still widely used 980 nm light. Moreover, these water-dispersed nanoplatforms offer interesting assets as triggers/probes for biomedical applications, by virtue of a plethora of emission bands (spanning the 380-1600 nm range). Our results pave the way to use these RENPs for UV/visible-triggered photodynamic therapy/drug release, while simultaneously tracking the nanoparticle biodistribution and monitoring their therapeutic action through the near-infrared signal that overlaps with biological transparency windows.