Chun Wu

Recent advances in iridium(III) complex-assisted nanomaterials for biological applications

Phosphorescent iridium(iii) complexes have gained increasing attention in biological applications owing to their excellent photophysical properties and efficient transportation into live cells. Their advantageous properties make them useful tools for enabling the intracellular detection of many different species for biological and medical applications. In this review, we summarize recent studies on the combination of iridium(iii) complexes and nanomaterials for intracellular sensing, drug delivery and photodynamic therapy. Various mechanisms and application modes are described and compared, and the outlook and future directions of this field are discussed as well.

Small Molecule Pin1 Inhibitor Blocking NF-κB Signaling in Prostate Cancer Cells

Prolyl-isomerase 1 (Pin1) is a conserved enzyme that regulates cell processes such as cell cycle progression, transcriptional regulation, and apoptosis. However, overexpression of Pin1 is correlated with a higher probability of prostate tumor recurrence. We utilized a molecular docking technique to identify Pin1 inhibitors from a database of natural product and natural product-like compounds. The action of the hit compounds against Pin1 activity was studied using multiple methods, including a fluorometric enzymatic assay, co-immunoprecipitation, western blotting, cell thermal shiftm, and other techniques. We have identified compound 1 as a natural-product-like inhibitor of Pin1 activity via structure-based virtual screening and showed that compound 1 could target Pin1 and disrupt the interaction between Pin1 and the p65 subunit of NF-κB in cells. Furthermore, compound 1 reduced nuclear p65 (Thr254) phosphorylation and attenuated NF-κB activity in cells. Finally, compound 1 induced apoptosis in prostate cancer cells. Compound 1 represents a natural product-like Pin1 inhibitor that acts via targeting the Pin1-NF-κB interaction.

Turn-on Luminescent Probe for Hydrogen Peroxide Sensing and Imaging in Living Cells based on an Iridium(III) Complex–Silver Nanoparticle Platform

A sensitive turn-on luminescent sensor for H2O2 based on the silver nanoparticle (AgNP)-mediated quenching of an luminescent Ir(III) complex (Ir-1) has been designed. In the absence of H2O2, the luminescence intensity of Ir-1 can be quenched by AgNPs via non-radiative energy transfer. However, H2O2 can oxidize AgNPs to soluble Ag+ cations, which restores the luminescence of Ir-1. The sensing platform displayed a sensitive response to H2O2 in the range of 0−17 μM, with a detection limit of 0.3 μM. Importantly, the probe was successfully applied to monitor intracellular H2O2 in living cells, and it also showed high selectivity for H2O2 over other interfering substances.

The Development of G‐Quadruplex‐Based Assays for the Detection of Small Molecules and Toxic Substances

G-Quadruplexes can be induced to form guanine-rich DNA sequences by certain small molecules or metal ions. In concert with an appropriate signal transducer, such as a fluorescent dye or a phosphorescent metal complex, the ligand-recognition event can be transduced into a luminescent response. This focus review aims to highlight recent examples of aptamer-based and metal-mediated G-quadruplex assays for the detection of small molecules and toxic substances in the last three years. We discuss the mechanisms and features of the different assays and present an outlook and a perspective for the future of this field.

Group 8–9 Metal-Based Luminescent Chemosensors for Protein Biomarker Detection

The development of transition metal complex-based luminescent chemosensors has recently aroused increasing interest for protein biomarker labelling and detection, especially for the real-time diagnosis and treatment of disease. This is owing to their unique photophysical properties, particularly their long-lived and environmentally sensitive emission, which can be easily controlled via the structural modification of ligands. In this overview, we highlight recent examples of protein biomarker detection using group 8–9 metal-based luminescent chemosensors, including the frequently employed ruthenium(II) and iridium(III) complexes. Various mechanisms and sensing modes are described and compared, and the outlook and future directions of this field are discussed as well.

A long-lived ferrocene-conjugated iridium(III) complex for sensitive turn-on luminescence detection of traces of DMSO in water and human serum

The development of an efficient sensor for the determination of the DMSO content in aqueous solution is highly desirable in a number of chemical industries. Presented herein is a ferrocene-conjugated iridium(III) complex, which exhibits remarkable capability to detect traces of DMSO (<1% v/v) in aqueous solution through a turn-on luminescence sensing mechanism. The extraordinary sensitivity and selectivity of this newly developed complex for DMSO renders it as one of the most powerful DMSO sensors known.

Iridium-based probe for luminescent nitric oxide monitoring in live cells

Nitric oxide (NO) is an intra- and extracellular messenger with important functions during human physiology process. A long-lived luminescent iridium(III) complex probe 1 has been designed and synthesized for the monitoring of NO controllably released from sodium nitroprusside (SNP). Probe 1 displayed a 15-fold switch-on luminescence in the presence of SNP at 580 nm. The probe exhibited a linear response towards SNP between 5 to 25 μM with detection limit at 0.18 μM. Importantly, the luminescent switch-on detection of NO in HeLa cells was demonstrated. Overall, complex 1 has the potential to be applied for NO tracing in complicated cellular environment.