Autofluorescence-Free In Vivo Imaging Using Polymer-Stabilized Nd3+-Doped YAG Nanocrystals

• Published in: ACS applied materials & interfaces Vol. 12; no. 46; pp. 51273 - 51284
• Main Authors: Cantarano, Alexandra, Yao, Jingke, Matulionyte, Marija, Lifante, José, Benayas, Antonio, Ortgies, Dirk H, Vetrone, Fiorenzo, Ibanez, Alain, Gérardin, Corine, Jaque, Daniel, Dantelle, Géraldine
• Format: Journal Article
• Language: English
• Published: American Chemical Society 18-11-2020
• Subjects: Biological and Medical Applications of Materials and Interfaces; block copolymer; near-infrared fluorescence; autofluorescence removal; YAG:Nd3+ nanoparticles; nanothermometry; bioimaging
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c15514

Neodymium-doped yttrium aluminum garnet (YAG:Nd3+) has been widely developed during roughly the past 60 years and has been an outstanding fluorescent material. It has been considered as the gold standard among multipurpose solid-state lasers. Yet, the successful downsizing of this system into the nanoregimen has been elusive, so far. Indeed, the synthesis of a garnet structure at the nanoscale, with enough crystalline quality for optical applications, was found to be quite challenging. Here, we present an improved solvothermal synthesis method producing YAG:Nd3+ nanocrystals of remarkably good structural quality. Adequate surface functionalization using asymmetric double-hydrophilic block copolymers, constituted of a metal-binding block and a neutral water-soluble block, provides stabilized YAG:Nd3+ nanocrystals with long-term colloidal stability in aqueous suspensions. These newly stabilized nanoprobes offer spectroscopic quality (long lifetimes, narrow emission lines, and large Stokes shifts) close to that of bulk YAG:Nd3+. The narrow emission lines of YAG:Nd3+ nanocrystals are exploited by differential infrared fluorescence imaging, thus achieving an autofluorescence-free in vivo readout. In addition, nanothermometry measurements, based on the ratiometric fluorescence of the stabilized YAG:Nd3+ nanocrystals, are demonstrated. The progress here reported paves the way for the implementation of this new stabilized YAG:Nd3+ system in the preclinical arena.