Organelle-targeted photosensitizers (PSs) having luminescence properties are potential theranostic agents for simultaneous luminescence imaging and photodynamic therapy. Herein, we report a water-soluble luminescent cyclometalated Ir complex, Ir-Bp-Ly, as a lysosome-targeted theranostic probe. Ir-Bp-Ly exhibits exceptional photophysical properties, with good triplet-state quantum yield (0.90), singlet oxygen generation quantum yield (0.71 at pH 4), and long lifetime (1.47 μs). Interestingly, Ir-Bp-Ly localizes mostly in lysosomes due to the presence of morpholine units, suggesting its potential use as a lyso-tracker. Ir-Bp-Ly displays a notable PDT effect in C6 glioma cells, efficiently generating reactive oxygen species owing to close proximity between the energy levels of its triplet state and those of molecular oxygen ( O ). The mechanism of cell death has been studied through caspase-3/7 and flow cytometry analyses, which clearly established the apoptotic pathway.

This study deals with the synthesis of a gliadin-stabilized gold quantum cluster (AuQC) for the encapsulation of curcumin (CUR) and its targeted delivery to the cancer cell. CUR is an anticancer drug containing a hydrophobic polyphenol derived from the rhizome of Curcuma longa . The utilization of CUR in cancer treatment is limited because of suboptimal pharmacokinetics and poor bioavailability at the tumor site. In order to improve the bioavailability of CUR, we have encapsulated it into AuQCs stabilized by a proline-rich protein gliadin because proline-rich protein has the ability to bind a hydrophobic drug CUR. The encapsulation of CUR into the hydrophobic cavity of the protein was confirmed by various spectroscopic techniques. Compared to CUR alone, the encapsulated CUR was stable against degradation and showed higher pH stability up to pH 8.5. The encapsulation efficiency of CUR in AuQCs was calculated as 98%, which was much higher than the other reported methods. In vitro drug release experiment exhibited a controlled and pH-dependent CUR release over a period of 60 h. The encapsulated CUR-QCs exhibited less toxicity in the normal cell line (L929) and high toxicity in breast cancer (MDA-MB239). Thus, it can be used as a potential material for anticancer therapy and bioimaging.

Surface modification of superparamagnetic Fe3O4 nanoparticles using polymers (polyaniline/polypyrrole) was done by radio frequency (r.f.) plasma polymerization technique and characterized by XRD, TEM, TG/DTA and VSM. Surface-passivated Fe3O4 nanoparticles with polymers were having spherical/rod-shaped structures with superparamagnetic properties. Broad visible photoluminescence emission bands were observed at 445 and 580 nm for polyaniline-coated Fe3O4 and at 488 nm for polypyrrole-coated Fe3O4. These samples exhibit good fluorescence emissions with L929 cellular assay and were non-toxic. Magnetic hyperthermia response of Fe3O4 and polymer (polyaniline/polypyrrole)-coated Fe3O4 was evaluated and all the samples exhibit hyperthermia activity in the range of 42–45 °C. Specific loss power (SLP) values of polyaniline and polypyrrole-coated Fe3O4 nanoparticles (5 and 10 mg/ml) exhibit a controlled heat generation with an increase in the magnetic field.

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Organelle‐targeted photosensitizers with luminescence properties are potential theranostic agents for simultaneous imaging and photodynamic therapy. Described herein is a cyclometalated IrIII complex, Ir‐Bp‐Ly, that exhibits high triplet quantum yield and singlet‐oxygen‐generation efficiency. The close‐proximity energy levels between triplet energy states of Ir‐Bp‐Ly and molecular oxygen favors efficient singlet oxygen and reactive oxygen species (ROS) generation. The good lysosomal specificity of Ir‐Bp‐Ly leads to its increased efficacy as a photodynamic therapeutic and imaging agent. More information can be found in the Full Paper by A. Ajayaghosh et al. on page 10999 ff.