Based on our previous finding (Biochem. Biophys. Res. Commun., 223, 578-582, 1996) of singlet oxygen generation from coproporphyrin excreted on the skin surface from Propionibacterium acnes, we hypothesized that singlet oxygen formed in this way under UV exposure would promote peroxidation of skin surface lipids. We found that squalene was oxidized efficiently by singlet oxygen derived from cop...

The reaction of ozone with a number of biological molecules was found to produce singlet oxygen in high yield. At pH 7.0, the reaction of ozone with an equimolar amount of biological molecule produced the following singlet oxygen yields (mole of singlet oxygen/mole of ozone): cysteine, 0.49 +/- 0.02; methionine, 1.13 +/- 0.11; reduced glutathione, 0.33 +/- 0.02; albumin, 1.00 +/- 0.05; uric aci...

Reversible noninvasive control over the generation of singlet oxygen is demonstrated in a bicomponent system comprising a diarylethene photochromic switch and a porphyrin photosensitizer by selective irradiation at distinct wavelengths. The efficient generation of singlet oxygen by the photosensitizer is observed when the diarylethene unit is in the colorless open form. Singlet oxygen generatio...

In this paper we describe the development and testing of instruments to measure singlet molecular oxygen produced by the photodynamic process. Singlet oxygen is an active species in photodynamic therapy, and we are developing two instruments for PDT researchers with the goal of a real-time dosimeter for singlet oxygen. We discuss both an ultrasensitive point sensor, and an imaging system that p...

Filamentous Cercospora fungi are resistant to photosensitizing compounds that generate singlet oxygen. C. nicotianae photosensitizer-sensitive mutants were restored to full resistance by transformation with SOR1 (Singlet Oxygen Resistance 1), a gene recovered from a wild-type genomic library. SOR1 null mutants generated via targeted gene replacement confirmed the requirement for SOR1 in photose...

Photodynamic therapy (PDT) is a viable treatment option for a wide range of applications, including oncology, dermatology, and ophthalmology. Singlet oxygen is believed to play a key role in the efficacy of PDT, and on-line monitoring of singlet oxygen during PDT could provide a methodology to establish and customize the treatment dose clinically. This work is the first report of monitoring sin...

The study of singlet molecular oxygen production and reactivity has emerged as a rich and diverse area with implications in fields ranging from polymer science to cancer therapy. In this review, we address the photophysical properties of singlet oxygen and of the photosensitizers used in its generation. Photosensitizers based on organic molecules and coordination compounds are examined and comp...

In a study of aerobically perfused rat hearts, the in situ photoactivation (530-590 nm) of rose bengal (a process that leads to the production of singlet oxygen and superoxide) has been shown to lead to the rapid development of electrocardiographic abnormalities and arrhythmias. With rose bengal concentrations of 1,000, 500, 250, 100, and 50 nmol/l (n =6/group), photoactivation (3,600 lx) led t...

Photodynamic therapy (PDT) is a promising cancer treatment. PDT uses photosensitizers that are selectively retained in malignant tumors. When tumors, pretreated with the photosensitizer, are irradiated with visible light, a photochemical reaction occurs and tumor cells are destroyed. Oxygen molecules in their metastable singlet delta state, O2(∆), are believed to be the species that destroys ca...

Systematic in vitro studies on singlet oxygen luminescence kinetics have been carried out reconciling recently published contradictory results reported for sub-cellular singlet oxygen kinetics obtained with two different approaches: single cell and cell ensemble measurements. The singlet oxygen luminescence kinetics in two cell lines were investigated after incubation with three different photo...