title: Optimization of Bi3+in Upconversion Nanoparticles Induced Simultaneous Enhancement of Near-Infrared Optical and X-ray Computed Tomography Imaging Capability.
abstract: Bioimaging probes have been extensive studied for many years, while it is still a challenge to further improve the image quality for precise diagnosis in clinical medicine. Here, monodisperse NaGdF4:Yb3+,Tm3+,x% Bi3+(abbreviated as GYT-x% Bi3+, x = 0, 5, 10, 15, 20, 25, 30) upconversion nanoparticles (UCNPs) have been prepared through the solvothermal method. The near-infrared upconversion emission intensity of GYT-25% Bi3+has been enhanced remarkably than that of NaGdF4:Yb3+,Tm3+(GYT) with a factor of ∼60. Especially, the near-infrared upconversion emission band centered at 802 nm is 150 times stronger than the blue emission band of GYT-25% Bi3+UCNPs. Such high ratio of NIR/blue UCL intensity could reduce the damage to tissues in the bioimaging process. The possibility of using GYT-25% Bi3+UCNPs with strong near-infrared upconversion emission for optical imaging in vitro and in vivo was performed. Encouragingly, the UCL imaging penetration depth can be achieved as deep as 20 mm. Importantly, GYT-25% Bi3+UCNPs exhibit a much higher X-ray computed tomography (CT) contrast efficiency than GYT and iodine-based contrast agent under the same clinical conditions, due to the high X-ray attenuation coefficient of bismuth. Hence, simultaneous remarkable enhancement of NIR emission and X-ray CT signal in upconversion nanoparticles could be achieved by optimizing the doping concentration of Bi3+ions. Additionally, Gd3+ions in the UCNPs endow GYT-25% Bi3+UCNPs with T1-weighted magnetic resonance (MR) imaging capability.
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Pengpeng
authors.initials: P
authors.lastname: Lei
authors.affiliation: Department of Radiology, The Second Hospital of Jilin University , Changchun 130041, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.
authors.forename: Shuyan
authors.initials: S
authors.lastname: Song
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Lile
authors.initials: L
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.
authors.forename: Xiuling
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Kaimin
authors.initials: K
authors.lastname: Du
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street, Changchun 130022, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Zhang
keywords: Bi3+ ion; NaGdF4; signal enhancement; trimodal imaging; upconversion nanoparticles