Chemiluminescence from UVA–exposed skin: Separating photo-induced chemiluminescence from photophysical light emission

Mechanisms of blue light-induced eye hazard and protective measures: a review

The risk of blue light exposure to human health has attracted increased research attention. Blue light, with relatively high energy, can cause irreversible photochemical damage to eye tissue. Excessive exposure of the eye to blue light tends to cause a series of alterations, such as oxidative stress, mitochondrial apoptosis, inflammatory apoptosis, mitochondrial apoptosis and DNA damage, resulting in the development of dry eye disease, glaucoma, and keratitis. Accordingly, physical protection, chemical and pharmaceutical protective measures, gene therapy, and other methods are widely used in the clinical treatment of blue light hazard. We reviewed the studies on possible blue light-induced signaling pathways and mechanisms in the eye and summarized the therapeutic approaches to addressing blue light hazard.

Photodynamic activity of 2,6-diiodo-3,5-dithienylvinyleneBODIPYs and their folate-functionalized chitosan-coated Pluronic® F-127 micelles on MCF-7 breast cancer cells

A 2,6-diiodo-3,5-dithienylvinyleneBODIPY dye was prepared and encapsulated with folate-chitosan capped Pluronic[Formula: see text] F-127 to provide drug delivery systems for photodynamic therapy (PDT). Moderately enhanced singlet oxygen quantum yields were observed for the dye encapsulation complexes in water. The in vitro dark cytotoxicity and photodynamic activity were investigated on the human breast adenocarcinoma (MCF-7) cell line. Minimal dark cytotoxicity was observed for the BODIPY dyes in 5% DMSO and when encapsulated in folate-functionalized chitosan-coated Pluronic[Formula: see text] F-127 micelles, since the cell viability values are consistently greater than 80% over the 0-40 [Formula: see text] concentration range. Upon irradiation of the samples, significant cytocidal activity was observed for the encapsulation complex of a 2,6-diiodo-8-dimethylaminophenyl-3,5-dithienylvinyleneBODIPY dye with less than 50% viable cells observed at concentrations [Formula: see text].

Ultraviolet A radiation potentiates the cytotoxic and genotoxic effects of 7 H-dibenzo[c,g]carbazole and its methyl derivatives

7H-Dibenzo[c,g]carbazole (DBC) is a heterocyclic aromatic hydrocarbon that is carcinogenic in many species and tissues. DBC is a common environmental pollutant, and is therefore constantly exposed to sunlight. However, there are limited data exploring the toxicity of DBC photoexcitation products. Here, we investigated the impact of ultraviolet (UV) A radiation on the biological activity of DBC and its methyl derivatives, 5,9-dibenzo[c,g]carbazole and N-methyl dibenzo[c,g]carbazole, on human skin HaCaT keratinocytes. Co-exposure of HaCaT cells to UVA and DBC derivatives resulted in a sharp dose-dependent decrease in cell survival and apparent changes in cell morphology. Under the same treatment conditions, significant increases in DNA strand breaks, intracellular reactive oxygen species, and oxidative damage to DNA were observed in HaCaT cells. Consistent with these results, an apparent inhibition in superoxide dismutase, but not glutathione peroxidase activity, was detected in cells treated with DBC and its derivatives under UVA irradiation. The photoactivation-induced toxicity of individual DBC derivatives correlated with the electron excitation energies approximately expressed as the energy difference between the highest occupied and the lowest vacant molecular orbital. Our data provide the first evidence that UVA can enhance the toxicity of DBC and its derivatives. Photoactivation-induced conversion of harmless chemical compounds to toxic photoproducts associated with reactive oxygen species generation may substantially amplify the adverse health effects of UVA radiation and contribute to increased incidence of skin cancer.

The application of ultra-weak photon emission in dermatology

Ultra-weak photo emission (UPE) is a phenomenon closely associated with life and provides us a rare window to look into oxidative reactions in life directly without the aid of other agents. Dozens of independent studies have investigated UPE in skin in the last 2 decades. Skin serves as a convenient target for the application of UPE. As the outmost layer of our body, skin is also subjected to the influences from environmental factors such as ultraviolet light. Therefore UPE measurement can help us better understand the interaction between skin and the outside world. A variety of dermatological interventions may benefit from UPE studies. In particular, those treatments aiming to manage the oxidative status of the skin can be monitored directly by UPE measurements. In recent years, UPE has already been used as a valuable in vivo tool to assist the selection of better skin care ingredients and products. The knowledge gained by UPE studies of skin may also help generate new insights and new targets for future treatments. This review emphasizes in vivo and clinical measurement of UPE in skin. The applications of UPE in skin research related to antioxidants and sunscreens are discussed.