Design of a β-diketonate-Eu3+ complex-based time-gated luminescence probe for visualizing mitochondrial singlet oxygenElectronic supplementary information (ESI) available: Characterization of the new compounds. See DOI: 10.1039/c7nj03696e

• Main Authors: Wu, Jing, Xing, Yue, Wang, Huan, Liu, Hongjing, Yang, Mei, Yuan, Jingli
• Format: Journal Article
• Language: English
• Published: 04.12.2017
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c7nj03696e

Although molecular luminescent probes capable of detecting target analytes in an organelle of interest are especially appreciated, lanthanide complex-based organelle-targetable luminescent probes have rarely been developed. Herein, by using an anthryl-substituted terpyridine derivative, 4′-(9-anthryl)-2,2′:6′,2′′-terpyridine ( ATPY ), as a singlet oxygen ( 1 O 2 )-recognition ligand, and a diphenyl-containing β-diketone coligand, 6-(1′,1′′-diphenyl-4′-yl)-1,1,1,2,2,3,3-heptafluoro-4,6-hexanedione ( DHH ), a new β-diketonate-Eu 3+ complex-based luminescent probe, Eu(DHH) 3 (ATPY) , has been designed and synthesized for the time-gated luminescence imaging detection of 1 O 2 in the mitochondria of living cells. The probe showed only weak luminescence due to the quenching effect of the 9-anthryl group. After the specific reaction of the 9-anthryl group with 1 O 2 , the corresponding endoperoxide derivative that exhibited great quantum yield ( Φ = 53%), Eu(DHH) 3 (EP-ATPY) , was formed, accompanied by a remarkable luminescence enhancement. The luminescence response behaviors of Eu(DHH) 3 (ATPY) to 1 O 2 were investigated using two different 1 O 2 reaction systems in aqueous media. In addition, the time-gated luminescence imaging study has demonstrated the applicability of the probe for monitoring the 1 O 2 generation in 5-aminolevulinic acid (a drug for photodynamic therapy) loaded HepG2 cells with high sensitivity and selectivity. Furthermore, by coloading the probe and a mitochondrial indicator, Mito-Tracker Green, into HepG2 cells, the mitochondria-targetable feature of the probe has also been confirmed by confocal luminescence imaging measurements. A β-diketonate-Eu 3+ complex-based time-gated luminescence probe was developed for highly sensitive monitoring of mitochondrial singlet oxygen during the photodynamic therapy process.