Concanavalin A Delivers a Photoactive Protein to the Bacterial Wall.

Modular supramolecular complexes, where different proteins are assembled to gather targeting capability and photofunctional properties within the same structures, are of special interest for bacterial photodynamic inactivation, given their inherent biocompatibility and flexibility. We have recently proposed one such structure, exploiting the tetrameric bacterial protein streptavidin as the main building block, to target protein A. To expand the palette of targets, we have linked biotinylated Concanavalin A, a sugar-binding protein, to a methylene blue-labelled streptavidin.

NanoFN10: A High-Contrast Turn-On Fluorescence Nanoprobe for Multiphoton Singlet Oxygen Imaging.

An "off-on" fluorescent nanoprobe for near-infrared multiphoton imaging of singlet oxygen has been developed. The nanoprobe comprises a naphthoxazole fluorescent unit and a singlet-oxygen-sensitive furan derivative attached to the surface of mesoporous silica nanoparticles. In solution, the fluorescence of the nanoprobe increases upon reaction with singlet oxygen both under one- and multiphoton excitation, with fluorescence enhancements up to 180-fold.

A near-infrared light-activatable Ru(ii)-coumarin photosensitizer active under hypoxic conditions.

Photodynamic therapy (PDT) represents a promising approach for cancer treatment. However, the oxygen dependency of PDT to generate reactive oxygen species (ROS) hampers its therapeutic efficacy, especially against hypoxic solid tumors. In addition, some photosensitizers (PSs) have dark toxicity and are only activatable with short wavelengths such as blue or UV-light, which suffer from poor tissue penetration.

Exploring Structure-Activity Relationships in Photodynamic Therapy Anticancer Agents Based on Ir(III)-COUPY Conjugates.

Photodynamic therapy holds great promise as a non-invasive anticancer tool against drug-resistant cancers. However, highly effective, non-toxic, and reliable photosensitizers with operability under hypoxic conditions remain to be developed. Herein, we took the advantageous properties of COUPY fluorophores and cyclometalated Ir(III) complexes to develop novel PDT agents based on Ir(III)-COUPY conjugates with the aim of exploring structure-activity relationships.

Mitochondria-Targeted COUPY Photocages: Synthesis and Visible-Light Photoactivation in Living Cells.

Releasing bioactive molecules in specific subcellular locations from the corresponding caged precursors offers great potential in photopharmacology, especially when using biologically compatible visible light. By taking advantage of the intrinsic preference of COUPY coumarins for mitochondria and their long wavelength absorption in the visible region, we have synthesized and fully characterized a series of COUPY-caged model compounds to investigate how the structure of the coumarin caging group affects the rate and efficiency of the photolysis process. Uncaging studies using yellow (560 nm) and red light (620 nm) in phosphate-buffered saline medium have demonstrated that the incorporation of a methyl group in a position adjacent to the photocleavable bond is particularly important to fine-tune the photochemical properties of the caging group.