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

Abstract

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.

Constructing anion–π interactions in cationic iridium(iii) complexes to achieve aggregation-induced emission properties

“…and exhibit great potential in the photoelectric and biomedical fields. [40][41][42][43][44][45] The intrinsic counter anion is an important component of the iridium(III) complex, which can not only modulate the intermolecular interactions but also affect the excited state nature. 46 However, the structure relaxation between the ground state and excited state as well as π-π stacking will lead to poor efficiency of the resulting iridium(III) complexes.…”

An ALP-responsive, anionic iridium complex for specific recognition of osteosarcoma cells

“…Canonical bidentate N-coordinated (N–N) Ir( iii ) complexes are usually cationic. Recently, we have developed phosphonate-containing N–N Ir( iii ) complexes 29,30 that are negatively charged and highly water-soluble after the deprotonation of phosphonate groups under physiological conditions. More importantly, these anionic Ir( iii ) complexes exhibit aggregation-induced emission (AIE) features, indicating that they are non-emissive in the diluted, unaggregated state but become highly luminescent upon aggregation at the target site.…”

Studies of Anticancer Activities In Vitro and In Vivo for Butyltin(IV)–Iridium(III) Imidazole–Phenanthroline Complexes with Aggregation-Induced Emission Properties

“…The AIE effect refers to a photophysical phenomenon where luminescent material does not emit or has a weak glow when dissolved in a good solvent in the molecular form, however, this is highly luminescent in a poor solvent or in the aggregative state. The introduction of the AIE concept effectively addresses the phenomenon of fluorescence quenching in luminescent materials. − Many metal complexes or organic compounds with AIE have been designed. − Then, luminescent entities or complexes with AIE effects were widely applied in research related to ion detection, cell imaging, animal imaging, and anticancer drug development. − …”