Acceptor engineering of metallacycles with high phototoxicity indices for safe and effective photodynamic therapy

Abstract

Although metallacycle-based photosensitizers have attracted increasing attention in biomedicine, their clinical application has been hindered by their inherent dark toxicity and unsatisfactory phototherapeutic efficiency. Herein, we employ a π-expansion strategy...

Near-infrared metal agents assisting precision medicine: from strategic design to bioimaging and therapeutic applications

“…26a). 238 This strategy can simultaneously reduce dark toxicity and enhance phototoxicity, to obtain a higher PI value. These metallacycles enabled fluorescence tissue penetration and ROS penetration up to 7 mm.…”

Molecular Design of NIR-II Polymethine Fluorophores for Bioimaging and Biosensing

“…Besides, supramolecular encapsulation, in which polymethine fluorophores are encapsulated within a rigid, matching molecular container, can decrease aggregation and protect them from the surrounding water molecules. 65 As a proof of concept, Smith and co-workers designed a new supramolecular host/guest self-assembly method in which a series of cationic polymethine fluorophores was encapsulated by cucurbit [7]uril (CB7) to improve the quantum yield from 0.12% to 0.23% in aqueous solution (Figure 3E). 66 On the one hand, these host−guest complexes can effectively alter the π-electron distribution; on the other hand, employing a host to shield the dye guest from stacking with itself can decrease aggregation.…”

“…Compared with traditional imageology, including ultrasound imaging (US), X-ray computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), fluorescence imaging displays unique advantages, such as fine spatiotemporal resolution, real-time dynamics imaging, high sensitivity, and low cost. Modifying the tunable fluorophores or fluorescent materials in the biological environment could effectively achieve specific cell uptake and obtain high-resolution and low-background biological images. − Furthermore, these fluorophore-based fluorescence imaging techniques have also been widely used for drug distribution, metabolism assessment, disease treatment, and vascular bioimaging. − However, most current fluorophores are excited at short wavelengths (<900 nm). With the increased tissue penetration depth, they will suffer from serious photon scattering/absorption and high spontaneous fluorescence in vivo, resulting in the significantly compromised signal-to-background ratio (SBR), limiting their in vivo biological applications (Figure A). , Recent findings reveal that fluorescence imaging in the NIR-II window (1000–1700 nm) has lower photon absorption/scattering and deeper penetration depth in organisms, as well as minimal background autofluorescence to provide higher spatial resolution and improved SBR (Figure B,C); − thus, it has attracted significant attention for in vivo imaging.…”

Heterometallic ruthenium–osmium complexes: dual photodynamic and photothermal therapy for melanoma and drug-resistant lung tumourin vivo

“…The PDT can be applied in conjunction with one or more other therapies, such as photothermal therapy (PTT), photoacoustic therapy (PAT), photochemotherapy (PCT), and immunogenic cell death (ICD), to integrate their individual advantages, dramatically enhance treatment efficacy, and decrease drug dosage. [4][5][6] The PTT is oxygen-independent and can be simply performed in unison with PDT without the requirement of additional apparatus or reagents to induce the thermal ablation of tumours. 7 The PSs based on classic single molecule metal complexes, such as [Ru(bpy) 3 ] 2+ (bpy = 2,2′-bipyridine), [Ru(bpy) 2 (dppz)] 2+ (dppz = dipyrido[3,2-a:2′,3′-c]phenazine), [Ru(bpy) 2 ( pip)] 2+ ( pip = 2-phenyl-imidazo [4,5-f ] [1,10]phenanthroline), [Ir( ppy) 2 (bpy)] 2+ ( ppy = 2-phenylpyridine), and [Ir ( ppy) 2 ( pip)] 2+ , lack a photothermal conversion (PTC) capability.…”

“…The PDT can be applied in conjunction with one or more other therapies, such as photothermal therapy (PTT), photoacoustic therapy (PAT), photochemotherapy (PCT), and immunogenic cell death (ICD), to integrate their individual advantages, dramatically enhance treatment efficacy, and decrease drug dosage. 4–6…”