Photochemistry and Photobiology

In this manuscript, we demonstrate a visible-light driven dimerization of para-quinone methides using eosin Y catalyst via a reductive homocoupling process. This mild and operationally simple methodology was found to be compatible with a variety of differently substituted para-quinone methides and a broad range of tetra-arylethane derivatives were obtained in moderate to good yields (47%-87%).

The results reported herein demonstrate for the first time that typical reducing agents in an alkaline medium initiate chemiluminescence of luminol in the presence of hemin, and the efficiency of their action is comparable to that of hydrogen peroxide and exceeds it in the case of the superoxide anion. The pertinent implications of these findings refer to new possibilities for developing chemiluminescence assays and biosensors and to precautions for determining hydrogen peroxide using luminol and hemin in samples of unknown composition, most prominently, of biological origin...

Staphylococcus aureus is a global challenge to the clinical field and food industry. Therefore, the development of antimicrobial photodynamic therapy (aPDT) has become one of the valuable methods to control this pathogen. The antibacterial activity of photoinactivation by erythrosine (Ery) against S. aureus has been reported, but its modes of action are unclear. This study aimed to employ a proteomic approach to analyze modes of action of Ery-aPDT against S. aureus. We determined the antibacterial effect by Ery-aPDT assays, quantified reactive oxygen species (ROS) and injury to the cell membrane, and determined protein expression using a proteomic approach combined with bioinformatic tools...

Zinc methyl 3-hydroxymethyl-pyropheophorbides-a possessing an acylhydrazinylidene group at the 131 -position were prepared by chemically modifying chlorophyll-a, which were models of bacteriochlorophyll-d as one of the light-harvesting pigments in photosynthetic green bacteria. Similar to the self-aggregation of natural bacteriochlorophyll-d in the antenna systems called chlorosomes, some of the synthetic models self-aggregated in an aqueous Triton X-100 solution to give red-shifted and broadened visible absorption bands...

Healthcare-associated infections (HAI) are illnesses acquired during healthcare and are often the most important adverse event during healthcare. With the aim of increasing the effectiveness of disinfection/decontamination processes in the health service with safe and not promote microbial resistance, we propose the development of portable equipment associated with type C ultraviolet light (UVC). The efficiency of the irradiance emitted by the equipment (at dosages 3.5, 5.0, and 60 mJ/cm2 ) was determined by the action exerted after exposure against four different bacterial (Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) and three different fungi (Candida albicans, C...

Herein, we report the design, synthesis, and supramolecular behavior of 30 structurally diverse photoresponsive azobenzene molecular systems. To establish structure-property relationships, azobenzenes appended with N-picolinyl and/or N-benzyl groups tethered directly through carboxamides or via triazolylmethyl carboxamide linkages were explored. We have evaluated the photoswitching characteristics and thermal stability of the Z isomers through systematic studies. All the targets were also screened for their aggregation behavior and supramolecular aspects...

A photosynthetic antenna-reaction center model, BBA-PFCor comprised of N,N'-bis(biphenyl-4-yl)aniline (BBA) covalently functionalized to bis(pentafluoro)corrole moiety has been prepared and the contribution of the BBA as the photoinduced energy transfer antenna was investigated. UV-visible studies have shown that integrating the electron-rich BBA chromophore into the corrole core has broadened the soret band of the corrole moiety with the absorption spanning from 300 to 700 nm. Electrochemical studies, in corroboration with the computational calculations, revealed that, BBA moiety can act as an electron reservoir and, in the excited state, it would transfer the excited energy to the corrole moiety in the dyad...

It has been 30 years since Photofrin-PDT was approved for the treatment of bladder cancer in Canada. However, Photofrin-PDT failed to gain popularity due to bladder complications. The PDT with red light and IV-administered Photofrin could permanently damage the bladder muscle. We have been developing a new combination strategy of PpIX-PDT with singlet oxygen-cleavable prodrugs for NMIBC with minimal side effects, avoiding damage to the bladder muscle layer. PpIX can be excited by either green (532 nm) or red (635 nm) light...

Combining photodynamic antimicrobials with nonwovens is prospective. However, common photosensitizers still have drawbacks such as poor photoactivity and the inability to charge. In this study, a photodynamic and high-efficiency antimicrobial protective material was prepared by grafting bis benzophenone-structured 4,4-terephthaloyl diphthalic anhydride (TDPA) photosensitizer, and antimicrobial agent chlorogenic acid (CA) onto spunbond-meltblown-spunbond (SMS) membranes. The charging rates for · OH and H2 O2 were 6377...

Fish collagen peptide (FCP) has been extensively investigated as a natural product that can combat photoaging; however, its efficacy is limited by its singular composition. Compound collagen peptide powder (CCPP) is a novel functional food formulation that exhibits photoprotective properties and comprises FCP and a blend of natural botanical ingredients. The objective of this study was to investigate the efficacy of CCPP and its molecular mechanism. CCPP had a low molecular weight, facilitating its efficient absorption, and was abundant in amino acids, total polyphenols, and total flavonoids...

Critical elements of photodynamic therapy are a photosensitizing agent, light at a wavelength corresponding to an absorbance band of the agent, and sufficient oxygenation to create a cytotoxic concentration of reactive oxygen species. Other factors may promote efficacy, but these are critical.

Photocatalysis with plasmonic nanoparticles (NPs) is emerging as an attractive strategy to make and break chemical bonds. However, the fast relaxation dynamics of the photoexcited charge carriers in plasmonic NPs often result in poor yields. The separation and extraction of photoexcited hot-charge carriers should be faster than the thermalization process to overcome the limitation of poor yield. This demands the integration of rationally chosen materials to construct hybrid plasmonic photocatalysts. In this work, the enhanced photocatalytic activity of gold nanoparticle-titanium dioxide metal-semiconductor heterostructure (Au-TiO2 ) is used for the efficient regeneration of nicotinamide (NADH) cofactors...

5-Aminolevulinic acid (ALA) is a prodrug for protoporphyrin IX (PpIX)-mediated photodynamic therapy (PDT) and fluorescence-guided tumor surgery. We previously reported that lapatinib, a repurposed ABCG2 inhibitor, enhanced ALA-induced PpIX fluorescence and PDT by blocking ABCG2-mediated PpIX efflux. In the present study, we evaluated how the variation in ABCG2 activities/protein levels affected tumor cell response to the enhancement of PpIX/PDT by lapatinib and Ko143, an ABCG2 tool inhibitor. ABCG2 activities and protein levels were determined in a panel of human cancer cell lines...

The aim of this study was to compare the effectiveness of the Gaussian and Flat-Top profiles in proliferation and differentiation of mesenchymal stem cell of buccal fat pad. Based on the timing schedule and type of laser handpieces, the cells were assigned to a control group with no radiation, and two irradiation test groups (980 nm) with Flat-Top (F) (power of 1.1 W, beam area of 1 cm2 ) and standard Gaussian (G) (power of 0.7 W, beam area of 0.5 cm2 ) handpieces. Each test group was divided into three subgroups, receiving one time (60 J/cm2 ), two times (120 J/cm2 ), and three times (180 J/cm2 ) irradiation...

The nucleotide excision repair (NER) system removes UV photoproducts from genomic DNA and is controlled by the circadian clock. Given that small-molecule compounds have been developed to target various clock proteins, we examined whether the cryptochrome inhibitor KS15 and REV-ERB antagonist SR8278 could modulate keratinocyte responses to UV radiation in vitro. We observed that though SR8278 promoted cell viability in UVB-irradiated cells, it had little effect on NER or on the expression of the clock-regulated NER factor XPA...

Acceptor-donor-acceptor (A-D-A) molecular rotors have drawn substantial attention for their applications in monitoring temperature variations within cellular microenvironments, biomimetic photocatalysis, and bioimaging. In this study, we have synthesized two novel rotor molecules, NBN1 and NBN2, by incorporating benzodithiophene (BDT) as the donor core and naphthalic anhydride/naphthalimide (NA/NI) moieties as acceptors using Pd-catalyzed Stille coupling reactions. These molecules exhibited distinct charge transfer (CT) behavior in both their absorption and emission spectra and displayed prominent emission solvatochromism...

Antimicrobial photodynamic therapy (APDT) is a promising approach to overcome antimicrobial resistance. However, for widespread implementation of this approach, approved photosensitizers are needed. In this study, we used commercially available preparations (Calendulae officinalis floridis extract, Chamomillae recutitae floridis extract, Achillea millefolii herbae extract; Hypericum perforatum extract; Eucalyptus viminalis folia extract) as photosensitizers for inactivation of gram-negative (Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus) bacteria...

Pesticides can improve crops' yield and quality, but unreasonable applications of pesticides lead to waste of pesticides which are further accumulated in the environment and threaten human health. Developing the release of controlled drugs can improve the utilization rate of pesticides. Among these methods, light-controlled release is a new technology of controlled release, which can realize spatiotemporal delivery of drugs by light. Four compounds, named Imidacloprid-Thioacetal o-nitrobenzyl-Phenamacril (IMI-TNB-PHE), Imidacloprid-Thioacetal o-nitrobenzyl- Imidacloprid (IMI-TNB-IMI), Phenamacril-Thioacetal o-nitrobenzyl-Phenamacril (PHE-TNB-PHE), and Imidacloprid-Thioacetal o-nitrobenzyl-Imidacloprid Synergist (IMI-TNB-IMISYN), were designed and synthesized by connecting thioacetal o-nitrobenzyl (TNB) with pesticides TNB displaying simple and efficient optical properties in this work...

Lopezia racemosa is known as a "mosquito flower or perlilla." It is commonly found in corn crops. In traditional Mexican medicine, this plant is used to treat stomach cancer and urinary tract infections. Likewise, compounds and extracts isolated from plants have shown cytotoxic and anti-inflammatory effects. The objective of this study was to evaluate the photochemoprotective effect of topical treatment with the methanolic extract of L. racemosa (MELR) as a photochemoprotective agent against the harmful effects of UV irradiation (UVR) on a bacterial model and hairless mice...

Nucleic acids, lipids, and other cell components can be found within different types of extracellular vesicles (EVs), which include apoptotic bodies (ABs), large extracellular vesicles (LEVs), and small extracellular vesicles (SEVs). Release of LEVs from cells can be reduced by genetic or pharmacological inhibition of the enzyme acid sphinogomyelinase (aSMase), and indeed several studies have demonstrated a role for the clinically approved aSMase inhibitor imipramine in blocking LEV release, including in response to UVB exposure...