Photosensitizers For Imaging Guidedphotodynamic Therapy Research Articles

AIE based GSH activatable photosensitizer for imaging-guided photodynamic therapy.

A novel ferrocene decorated vinyl pyridinium-substituted tetraphenylethylene (TPEPY-S-Fc) linked by a disulfide bond was designed as a GSH activatable photosensitizer by aggregation-induced emission for imaging-guided photodynamic therapy of cancer cells.

A H₂O₂-Responsive Boron Dipyrromethene-Based Photosensitizer for Imaging-Guided Photodynamic Therapy.

In this study, we demonstrate a novel H2O2 activatable photosensitizer (compound 7) which contains a diiodo distyryl boron dipyrromethene (BODIPY) core and an arylboronate group that quenches the excited state of the BODIPY dye by photoinduced electron transfer (PET). The BODIPY-based photosensitizer is highly soluble and remains nonaggregated in dimethyl sulfoxide (DMSO) as shown by the intense and sharp Q-band absorption (707 nm). As expected, compound 7 exhibits negligible fluorescence emission and singlet oxygen generation efficiency. However, upon interaction with H2O2, both the fluorescence emission and singlet oxygen production of the photosensitizer can be restored in phosphate buffered saline (PBS) solution and PBS buffer solution containing 20% DMSO as a result of the cleavage of the arylboronate group. Due to the higher concentration of H2O2 in cancer cells, compound 7 even with low concentration is particularly sensitive to human cervical carcinoma (HeLa) cells (IC50 = 0.95 μM) but hardly damage human embryonic lung fibroblast (HELF) cells. The results above suggest that this novel BODIPY derivative is a promising candidate for fluorescence imaging-guided photodynamic cancer therapy.

Polypeptide-based artificial erythrocytes conjugated with near infrared photosensitizers for imaging-guided photodynamic therapy

Photodynamic therapy (PDT) combining with near infrared (NIR) imaging is attractive. However, the intrinsic hypoxia in tumor and consumption of oxygen during treatment will decrease PDT. Here an artificial red cell was prepared using polypeptides conjugated hemoglobin as an oxygen carrier. A NIR photosensitizer-brominated 4,4-difluoro-4-bora-3a,a-diaza-s-indacene (BODIPY-Br2) possessing both high fluorescence emission and singlet oxygen generation efficiency was synthesized and also conjugated to polypeptides to achieve NIR imaging-guided PDT. In vitro studies performed on HepG2 cancer cells verified the oxygen carrier, cancer tracing and curing abilities of the as-prepared polymeric nanoparticles. Even under hypoxia condition, it also obviously increases the cell killing rate when exposed light at a low energy (25 mW/cm2, 10 min). Meanwhile, the fluorescence of BODIPY in NPs would light up cells for real-time imaging. These results show the potential of the biocompatible and biodegradable P-Hb-B NPs for enhancement of simultaneous tracing and treating of cancer.