Journal Article

Simultaneous Nanothermometry and Deep‐Tissue Imaging

Pratsinis, Sotiris E., Gerken, Lukas R. H., Herrmann, Inge K., Niedbalka, David, Gschwend, Pascal M.

2020

Overview

Bright, stable, and biocompatible fluorescent contrast agents operating in the second biological window (1000–1350 nm) are attractive for imaging of deep‐lying structures (e.g., tumors) within tissues. Ideally, these contrast agents also provide functional insights, such as information on local temperature. Here, water‐dispersible barium phosphate nanoparticles doped with Mn5+ are made by scalable, continuous, and sterile flame aerosol technology and explored as fluorescent contrast agents with temperature‐sensitive peak emission in the NIR‐II (1190 nm). Detailed assessment of their stability, toxicity with three representative cell lines (HeLa, THP‐1, NHDF), and deep‐tissue imaging down to about 3 cm are presented. In addition, their high quantum yield (up to 34%) combined with excellent temperature sensitivity paves the way for concurrent deep‐tissue imaging and nanothermometry, with biologically well‐tolerated nanoparticles. Non‐toxic Mn5+‐doped Ba3(PO4)2 nanoparticles smaller than 100 nm are prepared by scalable flame aerosol technology exhibiting ultrabright fluorescence in the preferred spectral region for bioimaging above 1000 nm. They can serve also as nanothermometers within tissues by capitalizing on their temperature‐dependent emission with high quantum yields. The nanoparticle stability, biocompatibility and deep‐tissue imaging down to about 3 cm are elucidated.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: Annealing / Barium / bioimaging / Communication / Communications / cytocompatibility / flame spray pyrolysis / intravital microscopy / Mn5+‐doped Ba3(PO4)2 / Nanoparticles / Particle size / Quantum dots