Abstract

The development of new methods for the detection of redox cycle is important for biological and clinical diagnoses. Here, a new cyclometalated iridium complex, (4-(2-pyridyl) benzaldehyde)₂Ir (5-chloro-1,10-phenanthroline) ([(4-pba)₂Ir(5-Cl-phen)]PF₆, probe 1), has been synthesized and applied to rapid, sensitive, and reversible detection and imaging of redox cycle HSO3-/H₂O₂ in living cells. The probe 1 is synthesized by using 4-(2-pyridyl) benzaldehyde as main ligand and 5-chloro-1,10-phenanthroline as ancillary ligand. Probe 1 exhibited “off–on–off” photoluminescence (PL) signal change in response to HSO3- and H₂O₂ in aqueous solution within 1 min. The change of PL intensity is proportional to HSO3- concentration from 40 μM to 300 μM and to H₂O₂ concentration from 40 μM to 260 μM. The detection limit is 10 μM for HSO3- and 20 μM for H₂O₂. Additionally, probe 1 was applied to detect HSO3- in food samples with satisfactory results. More importantly, PL imaging of HeLa cells indicates that probe 1 is able to image redox cycle HSO3-/H₂O₂ in living cells.

© 2019 The Author(s)

Using a redox-sensitive phosphorescent probe for optical evaluation of an intracellular redox environment

Shujuan Liu, Na Zhou, Zejing Chen, Huanjie Wei, Yana Zhu, Song Guo, and Qiang Zhao
Opt. Lett. 42(1) 13-16 (2017)

Time-resolved luminescence imaging of intracellular oxygen levels based on long-lived phosphorescent iridium(III) complex

Shujuan Liu, Yangliu Zhang, Hua Liang, Zejing Chen, Ziyu Liu, and Qiang Zhao
Opt. Express 24(14) 15757-15764 (2016)

Phosphorescent ion-paired iridium(III) complex for ratiometric and time-resolved luminescence imaging of intracellular biothiols

Shujuan Liu, Aqiang Xu, Zejing Chen, Yun Ma, Huiran Yang, Zhengjian Shi, and Qiang Zhao
Opt. Express 24(25) 28247-28255 (2016)

Strong triplet excited-state absorption in a phenanthrolinyl iridium(III) complex with benzothiazolylfluorenyl-substituted ligands

Timothy M. Pritchett, Michael J. Ferry, William M. Shensky, Andrew G. Mott, David J. Stewart, Stephanie L. Long, Joy E. Haley, Zhongjing Li, and Wenfang Sun
Opt. Lett. 40(2) 186-189 (2015)

Fluorescence intensity and lifetime redox ratios detect metabolic perturbations in T cells

Linghao Hu, Nianchao Wang, Elizabeth Cardona, and Alex J. Walsh
Biomed. Opt. Express 11(10) 5674-5688 (2020)