Photochemistry and Photobiology

Intrauterine adhesion (IUA), a major cause of uterine infertility, is pathologically characterized by endometrial fibrosis. Current treatments for IUA have poor efficacy with high recurrence rate, and restoring uterine functions is difficult. We aimed to determine the therapeutic efficacy of photobiomodulation (PBM) therapy on IUA and elucidate its underlying mechanisms. A rat IUA model was established via mechanical injury, and PBM was applied intrauterinely. The uterine structure and function were evaluated using ultrasonography, histology, and fertility tests...

Log dose-response curves relating to the effect of mitochondrial photodamage on clonogenic survival using benzoporphyrin derivative. With wild-type cells, autophagy produces a "shoulder" on the curve which is absent when an ATG5 knockdown is examined. Loss of ATG5 prevents the process of autophagy, which is seen to be cytoprotective.

In the present work, carbon nitride quantum dots (CNQDs) modified cobalt phosphate (CoPi) composites CNQDs/CoPi-x (x=1, 2, 3) were prepared at room temperature and characterized by FTIR, XRD, UV-Vis DRS, EIS, SEM, TEM/HR-TEM, XPS, and N2 gas adsorption. The morphologies and surface areas of CNQDs/CoPi-x have no remarkable change after modification of CNQDs, compared with pure CoPi. The obtained CNQDs/CoPi-x shows enhanced activity and stability of photocatalytic H2 evolution compared to pure CoPi using Eosin Y (EY) as a sensitizer and triethanolamine as an electron donor...

We report the evaluation of chiral nematic liquid crystal (CNLC) in blocking ultraviolet (UV). The CNLC was coated on calcium fluoride substrate to measure the spectral transmittance, was measured to detect the UV blocking effect of CNLC. The results show that CNLC could reduce UVB (290-320 nm) by 99.9% and UVA (320-400 nm) by 95.6%. The barrier effect of cake-shaped semi-solidified CNLC microspheres was further investigated, and it was found that cake-shaped semi-solidified CNLC microspheres could reduce UVB by 58...

Light, magnetic field and methylation affected the growth and secondary metabolism of fungi. The regulation effect of the three factors on the growth and Monascus pigments (MPs) synthesis of M. purpureus was investigated in this study. 5-azacytidine (5-AzaC), DNA methylation inhibitor, was used to treat M. purpureus (wild-type, WT). 20 μM 5-AzaC significantly promoted the growth, development and MPs yield. Moreover, 250 lux red light and red light coupled magnetic field (RLCMF) significantly promoted the biomass...

Recent experimental studies have indicated the potential for ultraviolet-C irradiation at 222nm (Far-UVC) to be used in occupied rooms to safely reduce exposure to airborne pathogens. We present simulations applying a Monte Carlo radiation transfer model with a computational fluid dynamics model to predict the spatial variation in airborne microorganism inactivation. Our simulations effectively reproduce data from steady state experiments in a room-sized bio-aerosol chamber for the reduction of aerosolised Staphylococcus aureus...

Far-UVC, from filtered Krypton-Chloride lamps, is promising for reducing airborne transmission of disease. Whilst significant research has been undertaken to investigate skin safety of these lamps, less work has been undertaken on eye safety. There is limited data on human eye safety or discomfort from the deployment of this germicidal technology. In this pilot study, immediate and delayed eye discomfort were assessed in a simulated office environment with deployment of Krypton-Chloride lamps, located on the ceiling and directed downwards into the occupied room...

An acetylated riboflavin derivative, 3-methyl-tetraacetyl riboflavin (3MeTARF), is a compound with high photostability and photophysical properties similar to riboflavin, including the ability to photogenerate singlet oxygen. In the present study, we compared the effects of irradiation on A431 cancer cells with blue LED light (438 nm) in the presence of 3MeTARF and riboflavin on MAPK phosphorylation, apoptosis, caspase 3/7 activation and PARP cleavage. We observed that photogenerated oxidative stress in this reaction activates MAPK by increasing phosphorylation of p38 and JNK proteins...

It has been proposed that transient and reversible phenotypic changes could modify the response of bacteria to germicidal radiation, eventually leading to tailing in the survival curves. If this were the case, changes in susceptibility to radiation would reflect variations in gene expression, and should only occur in cells in which gene expression is active. To obtain experimental evidence supporting the involvement of phenotypic changes in the origin of tailing, we studied changes in the susceptibility to radiation of cells able to survive high fluences, using split irradiations...

Sphingolipids are involved in the maintenance of the skin barrier function and regulate cellular processes of keratinocytes. The work reported here is designed to uncover details of the mechanism of damage to such lipids by UV radiation. Our approach employs laser flash photolysis and electron paramagnetic resonance (EPR) spectrometry to explore the mechanism of the decay reactions, and to determine the associated kinetic parameters. To interpret our experiments, we computed both excitation energies and EPR parameters of radicals formed during photolysis...

Lipid oxidation by reactive oxygen species (ROS) provide several different oxidation products that have been implicated in inflammatory responses. Ground state atomic oxygen [O(3 P)] is produced by the photodeoxygenation of certain heterocyclic oxides and has a reactivity that is unique from other ROS. Due to the reactive nature of O(3 P), the site of O(3 P)-generation is expected to influence the products in heterogenous solutions or environments. In this work, the oxidation of low-density lipoprotein (LDL) by lipids with covalently bound O(3 P)-photoprecursors was compared to more hydrophilic O(3 P)-photoprecursors...

UVB-induced photoaging is characterized by wrinkle formation, slackness, and senile plaques, affecting the health and beauty of human being. Our previous study revealed that exosomes derived from adipose-derived stem cells (ADSCs) could efficiently alleviate UVB-induced photodamage. However, the functional ingredients in exosomes were undefined. LncRNA H19, one of the well-researched lncRNAs in exosomes, exhibits multiple physiological effects. This study aims to demonstrate the photo-protective role of lncRNA H19 on skin photoaging in UVB-irradiated human skin fibroblasts cells (HSFs) and Kunming mice...

Mesoporous silica nanoparticles (MSNs) are widely known for their versatile applications. One of the most extended is as drug delivery systems for the treatment of cancer and other diseases. This review compiles the most representative examples in the last years of functionalized MSNs as photosensitizer carriers for photodynamic therapy (PDT) against cancer. Several commercially available photosensitizers (PSs) demonstrated poor solubility in an aqueous medium and insufficient selectivity for cancer tissues...

In this article the synthesis of a new hybrid compound, candidate as photothermal agent, is proposed, based on TDPP (3,6-di(thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) and toluidine blue. Electronic structure calculations at the DFT, TD-DFT and CCSD level of theories were performed to obtain ground and excited states molecular structures, photophysical properties and absorption spectrum of the hybrid and the starting compounds. Additionally, ADMET calculations were performed to predict the pharmacokinetic, metabolic and toxicity properties of the proposed compound...

In the context of photodynamic therapy, reports periodically turn up in journals where reviewers are apparently unacquainted with the essentials. Bizarre procedures and results can thereby appear. This appears to be a byproduct of the publishing industry, especially for some of the "pay to play" options.

The highly transmittable nature of SARS-CoV-2 has increased the necessity for novel strategies to safely decontaminate public areas. This study investigates the efficacy of a low irradiance 405-nm light environmental decontamination system for the inactivation of bacteriophage phi6 as a surrogate for SARS-CoV-2. Bacteriophage phi6 was exposed to increasing doses of low irradiance (~0.5 mW cm-2 ) 405-nm light whilst suspended in SM buffer and artificial human saliva at low (~103-4 PFU mL-1 ) and high (~107-8 PFU mL-1 ) seeding densities, to determine system efficacy for SARS-CoV-2 inactivation and establish the influence of biologically-relevant suspension media on viral susceptibility...

The translation of photodynamic effects into clinical practice is a complex process that involves the pharmacokinetics of photosensitizing agents, light dosimetry and oxygenation levels. But even the 'translation' of basic photobiology into meaningful pre-clinical information can be challenging. Some thoughts on directions for progress in clinical trials are suggested.

No abstract text is available yet for this article.

The study evaluates compatibility of stabilizers with dye dopped liquid crystal (LC) scaffolds that are used in electronically dimmable materials. The photodegradation of the materials were investigated and suitable stabilizers were evaluated to slow the degradation process. Various types of benzotriazole based stabilizers were evaluated for stabilizing the liquid crystals Based on spin trapping experiments radical generated upon UV exposure is likely responsible for the degradation of the system. The radical generation is competitively inhibited by the addition of stabilizers...

Ultraviolet (UV) radiation can elicit both bactericidal and bacteriostatic activity depending on light parameters and targeted bacteria. Current methods based on bacterial growth on solid medium allow measurement of only bactericidal but not bacteriostatic activity, while liquid cultures exhibit low light penetration. Here, we propose a method to quantify both bactericidal and bacteriostatic activity of radiation based on (a) bacterial cultures on solid medium, (b) acquisition and quantitative analysis of photographic images of plates containing bacterial colonies, (c) application of two mathematical equations to evaluate bactericidal and bacteriostatic activity...