Photo- and Electrochemical Dual-Responsive Iridium Probe for Saccharide Detection.

Dual detection systems are of interest for rapid, accurate data collection in sensing systems and in vitro testing. We introduce an IrIII complex with a boronic acid receptor site attached to the 2-phenylpyridine ligand as an ideal probe with photo- and electrochemical signals that is sensitive to monosaccharide binding in aqueous solution. The complex displays orange luminescence at 618 nm, which is reduced by 70 and 40 % upon binding of fructose and glucose, respectively. The electro-chemiluminescent signal of the complex also shows a direct response to monosaccharide binding. The IrIII complex shows the same response upon incorporation into hydrogel matrices as in solution, thus demonstrating the potential of its integration into a device, as a nontoxic, simple-to-use tool to observe sugar binding over physiologically relevant pH ranges and saccharide concentrations. Moreover, the complex's luminescence is responsive to monosaccharide presence in cancer cells.

Construction of photofunctional peptide conjugates through selective modification of N-terminal cysteine with cyclometallated iridium(III) 2-formylphenylboronic acid complexes for organelle-specific imaging, enzyme activity sensing and photodynamic therapy.

Luminescent cyclometallated iridium(III) complexes bearing a 2-formylphenylboronic acid moiety were designed; one of the complexes was utilised to modify peptides containing an N-terminal cysteine to afford luminescent conjugates with selective organelle-targeting or furin-responsive properties.

Bioorthogonal dissociative rhenium(i) photosensitisers for controlled immunogenic cell death induction.

Photosensitisers for photoimmunotherapy with high spatiotemporal controllability are rare. In this work, we designed rhenium(i) polypyridine complexes modified with a tetrazine unit via a bioorthogonally activatable carbamate linker as bioorthogonally dissociative photosensitisers for the controlled induction of immunogenic cell death (ICD). The complexes displayed increased emission intensities and singlet oxygen (1O2) generation efficiencies upon reaction with trans-cyclooct-4-enol (TCO-OH) due to the separation of the quenching tetrazine unit from the rhenium(i) polypyridine core. One of the complexes containing a poly(ethylene glycol) (PEG) group exhibited negligible dark cytotoxicity but showed greatly enhanced (photo)cytotoxic activity towards TCO-OH-pretreated cells upon light irradiation. The reason is that TCO-OH allowed the synergistic release of the more cytotoxic rhenium(i) aminomethylpyridine complex and increased 1O2 generation. Importantly, the treatment induced a cascade of events, including lysosomal dysfunction, autophagy suppression and ICD. To the best of our knowledge, this is the very first example of using bioorthogonal dissociation reactions as a trigger to realise photoinduced ICD, opening up new avenues for the development of innovative photoimmunotherapeutic agents.

Photofunctional cyclometallated iridium(III) polypyridine methylsulfone complexes as sulfhydryl-specific reagents for bioconjugation, bioimaging and photocytotoxic applications.

We report herein near-infrared (NIR)-emitting cyclometallated iridium(III) complexes bearing a heteroaromatic methylsulfone moiety as sulfhydryl-specific reagents; one of the complexes was conjugated to cysteine and cysteine-containing peptides and proteins for bioimaging and photocytotoxic applications.

Tuning the organelle specificity and cytotoxicity of iridium(III) photosensitisers for enhanced phototheranostic applications.

Luminescent cyclometallated iridium(III) complexes with a polyhedral oligomeric silsesquioxane (POSS) unit were designed as efficient theranostic agents that displayed tuneable organelle-targeting properties, minimal dark cytotoxicity and substantial photocytotoxicity even under hypoxic conditions.