New cyclometalated transition-metal based photosensitizers for singlet oxygen generation and photodynamic therapy

The aim of this review article is to introduce recent studies on an emergent class of singlet oxygen photosensitizers of potential applications to the photodynamic therapy,with a primary focus on the cyclometalated transition-metal complexes.Singlet oxygen photosensitization performances of various cyclometalated Ir and Pt scaffolds are reviewed,and the general photophysical properties of relevant systems and the mechanisms of singlet oxygen production via photo-sensitization are also briefly discussed.Thus far,investigations of singlet oxygen sensitization by such Ir and Pt complexes are mainly carried out in organic solvents and under non-physiological conditions,while some research efforts have been made at examining the feasibility of applying pertinent cyclometalated complexes to photodynamic therapy.

Multifunctional Reduced Graphene Oxide Hydrogel as Drug Carrier for Localized and Synergic Photothermal/Photodynamics/Chemo Therapy

To combine localized drug release with multimodal therapy for malignant tumor, a composite hydrogel as an integrative drug delivery system was facilely prepared. The system contains spinach extract （SE）, reduced graphene oxide （rGO） and gold nanocages （AuNCs）. SE conduces to the formation of hydrogel, and also serves as a green material for improving the biocompatibility of hydrogel, and a natural pho- tosensitizer for killing tumor cells under laser radiation （fi60 nm）. AuNts show obvious photothermy and can enhance the generation of cytotoxic singlet oxygen （102）. The composite hydrogel shell on tumor cells exhibits several competitive advantages including enhanced antitumor effect by retaining the high con- centration of drugs around cancer cell, excellent PDT/FFr compatibility as well as high loading and controllable release of fluorouracil （5-FU） for synergetic multimodal treatment. The survival rate of HeLa cells incubated with 5-FU loaded hydrogel under NIR radiation for 10 min sharply decreases to 1.2%, in- dicating remarkably improved antitumor effects. These results demonstrate that the hydrogel is an excellent delivery carrier for localizable, NIR-responsive and combined PTT/PDT/Chemo synergetic antitumor.

Semiconducting polymer dots with photosensitizer loading and peptide modification for enhanced cell penetration and photodynamic effect

This letter describes semiconducting polymer dots （Pdots） doped with a photosensitizer and modified with a cell penetrating peptide for photodynamic therapy （PDT）. The resulting Pdots exhibited efficient singlet oxygen （^1O2） generation mediated by intraparticle energy transfer. Experimental results indicated that the peptide-coated Pdots could promote the cellular uptake and increase the penetration efficiency in vitro, and effectively suppressed tumor growth and enhanced the photodynamic effect in vivo. Our results demonstrate that Pdots with photosensitizer loading and peptide modification hold great promise for cancer therapy.