The development of an iridium(Ⅲ) complex functionalized G-quadruplex probe for the stability of G-quadruplex and lifetime image in cytoplasm

G-quadruplex(G4) is widely known as a non-classical secondary structure of nucleic acid. With the indepth study of G4, it is an urgent need for a phosphorescent probe with a high G4 binding ability to evaluate the level of G4 in the cytoplasm. Thus, this study designed and synthesized Ir-PDP where an Ir(Ⅲ)complex was used as a phosphorescent emitter. Meanwhile, two installed PDPs(pyridostatin derivatives)were used to improve the combination ability with G4 and reduced the cytotoxicity of the Ir(Ⅲ) complex.Compared with other nucleic acid secondary structures, Ir-PDP produced a higher phosphorescence lifetime after interacting with G4. Ir-PDP was distributed in the cytoplasm of living cells, and two-photon phosphorescence lifetime imaging can detect the binding events of the probe in the cytoplasm. The addition of G4 binder PDS significantly regulated cytoplasmic phosphorescence lifetime. The project explored a new sensing pathway to observe the binding manners of probes in the cytoplasm through the phosphorescence lifetime of probes.

A Cyclometalated Iridium（Ⅲ） Complex Serves as a Phosphorescent Probe for Specific Mitochondrial Imaging in Living Cells

A new cyclometalated iridium（Ⅲ） complex [Ir（2-pq）2（HPIP）]C1 （lrl, 2-pq=3-phenylisoquinoline, HPIP= 2-（2-hydroxyphenyl）imidazo[4,5-f] 1,10-phenanthroline） was synthesized and applied to image mitochondria in living cells. Irl displayed excellent ability to selectively accumulate in mitochondria of live cells with no requirement of replacement of the culture medium. Due to Irl exhibiting better photostability than the commercially available mitochondrial trackers, this complex could be applicable for the imaging and tracking of the mitochondrial mor- phological changes over long periods of time. In addition, in vitro cytotoxicity investigation revealed that it! showed negligible cytotoxicity at the concentrations employed. Based on these, Irl is suitable for organelle-selective imaging in living cells.

Bone analysis using an aggregation-induced emission-active iridium complex

Fluorescent analysis of bone provides valuable insights into bone structures.However,conventional dyes suffer from low specificity on bone tissue,small stokes shift,short fluorescent lifetime,and aggregation-caused quenching effect,which result in low efficacy and artifacts.In this work,we design an aggregation-induced emission(AIE)-active iridium(III)complex(Ir-BP2)as a highly selective,convenient,nondestructiveness,and dual-mode staining agent for bone analysis.Ir-BP2 containing phosphonate groups selectively binds to hydroxyapatites,the main component of bone matrix,and exhibits turn-on AIE phosphorescence with prolonged lifetime.Ir-BP2 exhibits promising biosafety and offers higher accuracy in staining calcium deposits than conventional Alizarin Red S staining assay when it is employed in real-time monitoring of osteogenesis differentiation process.A ready-to-use staining spray of Ir-BP2 is fabricated.By using fluorescent imaging and lifetime imaging,Ir-BP2 staining provides valuable insights into bone microstructure analysis,microdamage diagnosis,and bone growth state identification.Further,Ir-BP2 is successfully applied on a human spine vertebra for diagnosing bone invasiveness of eosinophilic granuloma,validating its clinical practice.This work presents a powerful tool in bone analysis and will lead to new approaches for the diagnosis and treatment of bone-related diseases.