Wavelength dependent functional excitation of rare earth nanoparticles – decoupling theranostics

Abstract

Rare earth based nanoparticles (RENPs) are bringing together multidisciplinary scientific research, towards the creation of superior theranostic tools within the biomedical framework. However, these theranostic agents are usually conceived with both therapeutic and diagnostic functions occurring simultaneously, yet to control them separately and on-demand would constitute a move towards safer and more precise multifunctional theranostics. We have designed and synthesized multilayered RENPs with the purpose of decoupling the optical diagnostic and therapeutic capabilities via excitation wavelength selectivity (Fig. 1). These decoupled RENPs operate entirely under the near-infrared (NIR) excitation, for minimized light interference with target and extended tissue depth action. Under 806 nm irradiation, RENPs behave solely as high-contrast NIR-to-NIR optical probes and nanothermometers. On the contrary, excited by light of 980 nm, RENPs emit UV/visible upconversion light, which can trigger secondary photochemical processes, e.g. generation of reactive oxygen species. Overall, this outlines a new direction in the development of state-of-the-art theranostic nanoplatforms. Further advancements in fundamental and clinical research focused on these type of RENPs will perfect their decoupled theranostic approach, creating perfectly controllable and truly multifunctional nanomedicines.