title: Nd(3+)-sensitized upconversion nanophosphors: efficient in vivo bioimaging probes with minimized heating effect.
abstract: Upconversion (UC) process in lanthanide-doped nanomaterials has attracted great research interest for its extensive biological applications in vitro and in vivo, benefiting from the high tissue penetration depth of near-infrared excitation light and low autofluorescence background. However, the 980 nm laser, typically used to trigger the Yb(3+)-sensitized UC process, is strongly absorbed by water in biological structures and could cause severe overheating effect. In this article, we report the extension of the UC excitation spectrum to shorter wavelengths, where water has lower absorption. This is realized by further introducing Nd(3+) as the sensitizer and by building a core/shell structure to ensure successive Nd(3+) → Yb(3+) → activator energy transfer. The efficacy of this Nd(3+)-sensitized UC process is demonstrated in in vivo imaging, and the results confirmed that the laser-induced local overheating effect is greatly minimized.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications & PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Ye-Fu
authors.initials: YF
authors.lastname: Wang
authors.forename: Gao-Yuan
authors.initials: GY
authors.lastname: Liu
authors.forename: Ling-Dong
authors.initials: LD
authors.lastname: Sun
authors.forename: Jia-Wen
authors.initials: JW
authors.lastname: Xiao
authors.forename: Jia-Cai
authors.initials: JC
authors.lastname: Zhou
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Yan
mesh_terms: D000042:Absorption; D000818:Animals; D003287:Contrast Media / Q000737:chemistry; D003952:Diagnostic Imaging / Q000379:methods*; D006361:Heating; D006358:Hot Temperature; D007259:Infrared Rays; D007834:Lasers; D049449:Luminescence; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D049329:Nanostructures / Q000737:chemistry*; D009354:Neodymium / Q000737:chemistry*; D010316:Particle Size; D010758:Phosphorus / Q000737:chemistry*; D010777:Photochemistry; D019265:Spectroscopy, Near-Infrared; D014867:Water / Q000737:chemistry
chemical_list: D003287:Contrast Media; D014867:Water; D010758:Phosphorus; D009354:Neodymium