Photochemical & Photobiological Sciences最新文献

Under the initiative of the United Nations Sustainable Development Goals (SDGs), utilization of clean energy for metallurgy has emerged as a new trend in recent years. Precious metal ions with low chemical reactivity have been readily photoreduced, while active metal such as copper has been rarely reported. In this work, photocatalytic reduction of Cu(II) ions was investigated utilizing TiO₂ nanoparticles as catalyst. By surface charge optimization in different anionic species-based cupric solution, nanoparticle products with Cu₂O as out shell and zero-valent Cu as the core have been photocatalytic prepared. The photocatalysis conditions such as catalyst amount, Cu(II) ions concentration, ethanol addition, and illumination wavelength were optimized, good cycling stability was confirmed. Argon etching results and thermogravimetric analysis confirmed the appearance of zero-valent Cu metal in the core of nanoparticle products. Ex situ photoreaction investigation revealed the consumption pathway of oxidative holes and photoreduction mechanism of Cu(II) ions. This research could provide some insights into the photoreduction method of active metals and the photocatalytic removal of heavy metal ions within the realm of environmental protection.

Photoaging is characterized by chronic inflammation in response to ultraviolet (UV) radiation. UV radiation causes skin cells to produce reactive oxygen species (ROS), which causes oxidative stress and inflammation. ROS can reversibly or irreversibly destroy different cellular compounds, including nucleic acids, proteins, free amino acids, lipids, lipoproteins, carbohydrates, and connective tissue macromolecules. Ferroptosis is a kind of programmed cell death caused by iron dependence and lipid peroxidation and has been recently discovered. Its occurrence is primarily related to iron metabolism, antioxidants, lipid peroxidation, and other processes. In addition, high levels of ROS can trigger oxidative stress, altering the redox balance within cells and thus initiating ferroptosis. Ferroptosis has been implicated in UV-driven skin photoaging. Moreover, UV radiation from sunlight can regulate numerous ferroptosis-linked genes. This review will focus on the function of ferroptosis in UV radiation-damaged skin cells. We hope to draw attention to the significance of ferroptosis regulation in the prevention and treatment of skin photoaging.

Metal-free photocatalysts, especially through the use of semi-conductors g-C₃N₄ (graphitic carbon nitride, CN) have become a prominent topic due to their sustainable advantages and promising effectiveness in hydrogen (H₂) production. However, CN material requires specific modifications, since its efficacy under visible light suffers from fast recombination of electron/hole pairs (e^‒/h⁺), slow charge transfer and limited surface area. In this study, we present the synthesis of CN via the thermal treatment of urea and melamine mixture. To enhance its crystallinity and photocatalytic performance, Pt nanoparticles were loaded onto CN by simple incipient wetness impregnation method. The H₂ production was investigated through the potential application of aromatic alcohols including anisyl (AA), benzyl (BA), piperonol (PA), and methanol (M) alcohols, as sacrificial reagents. H₂ production was achieved using the hybrid Pt-CN system with the added benefit of value-added organic synthesis under visible light exposure. The Pt-CN photocatalyst exhibited varying H₂ evolution rates on the alcohol used as sacrificial reagent, with the PA yielding to the highest rate of 503.5 µmol·g^-1·h^-1. Stability assessments confirmed the robustness of the synthesized Pt-CN photocatalyst across three consecutive visible light driven experiments. Notably, piperonal (P) synthesis occurred along with H₂ production under visible light. Comprehensive structural, textural, morphologic, optoelectronic and electrochemical characterizations were performed correlating the Pt-CN's properties with its visible photocatalytic performance.

A red-emitting excited-state intramolecular charge transfer pyridinium dye, [4-((1E,3E)-4-(4-(dimethylamino)phenyl)buta-1,3-dien-1-yl)-1-methylpyridin-1-ium] (DAPBMP), was synthesized and characterized using NMR and ESIMS studies. Binding interaction between dye DAPBMP and genomic DNA were investigated using steady-state and time-resolved spectroscopic methods. The thermodynamics of the interaction process were characterized using isothermal titration calorimetry (ITC) which reveals the key role of the hydrophobic effect and electrostatic interaction between the positive charged dye and the negatively charged polyphosphate of DNA backbone. The binding of dye to the minor groove of the DNA double helix is confirmed by circular dichroism spectroscopy and molecular docking simulation study. The binding interaction is found to be strongly dependent on the ionic strength of the medium as demonstrated by a systematic study in the presence of various concentrations of NaCl. A detailed calorimetric study shows that polyelectrolytic contribution, ΔGpe, (a measure of the role of electrostatic force) to the total free energy change (ΔG) of interaction progressively decreases with increasing ionic strength of the medium due to weakening of the DAPBMP:DNA binding by screening of the electrostatic charges. The fluorescence of DAPBMP exhibits a remarkable emission enhancement of almost 15 times when the viscosity of the water-propylene glycol system increases. Fluorescent microscopy was performed with C2C12 mouse skeletal myoblast and A549 lung cancer cells in the presence of DAPBMP dye. The dye passed through the C2C12 cell membrane and binds the negatively charged nucleic acids, essentially double-stranded DNA which made the nuclear puncta along with perinuclear located mitochondria.

Light is an environmental stimulus to which all living organisms are exposed. Numerous studies have shown that bacteria can modulate virulence factors through photoreceptor proteins. Xanthomonas campestris pv. campestris (Xcc) is the causative agent of the systemic vascular disease black rot, which affects cruciferous crops worldwide. Typical symptoms include V-shaped yellow lesions emanating from the leaf margins and blackening of the leaf veins. In previous work, we have shown that Xcc possesses a functional bacteriophytochrome (XccBphP) that regulates its virulence in response to red and far-red light. In addition to the XccBphP protein the Xcc genome codes for a blue light photoreceptor, a Light Oxygen Voltage (LOV) domain-containing protein with a histidine kinase (HK) as the output module. Here, we show that both photoreceptors are able to sense blue light. We demonstrated that XccLOV is a functional photoreceptor by performing loss and gain of function experiments with a knock-out and a complemented strain for the lov gene. Blue light negatively affected swimming motility, whereas xanthan production was regulated by XccBphP, in a blue light independent manner. Additionally, our studies showed that blue light altered biofilm structure patterns and enhanced virulence. Overall, these results revealed that some Xcc virulence factors are blue light modulated via at least two photoreceptors.

Current sunscreen messaging centres around skin cancer prevention, with an emphasis on mitigating the damaging effects of ultraviolet B (UVB) radiation. Darker skin is believed to be better protected against UVB owing to its higher melanin content, and therefore, this messaging has been largely targeted at people with lighter skin tones. This is reflected by low sunscreen use by people of darker skin types. However, visible light (VL) is now being appreciated as a culprit behind exacerbation of disorders of hyperpigmentation such as melasma and post-inflammatory hyperpigmentation (PIH) which is known to significantly impair quality of life (QoL) of those affected. The role of VL in melanogenesis is not well known to patients nor to dermatologists and is a missed opportunity in the management of pigmentary disorders. We propose that changing the terminology from 'sunscreen' to 'light protection' acknowledges the central role of VL in melanogenesis, underlining the importance of VL protection and making the messaging more inclusive for people of all skin colours.

The compound 4-(2-((1H-benzo[d]imidazol-2-yl) thio) phenoxy) phthalonitrile was obtained from the reaction of 2-nitrophenol, 4-nitrophthalonitrile and 2-mercaptobenzimidazole. This compound was reacted with magnesium Chloride (MgCl₂) to yield tetrakis-[(2-((1H-benzo[d]imidazol-2-yl) thio) phenoxy) phthalocyaninato] magnesium II. New compounds were characterized by UV-vis, ¹H NMR, ¹³C NMR, FTIR and Mass spectra. Electronic spectra aggregation study of magnesium phthalocyanine compound in various concentrations and diverse solvents was performed. Photoluminescence spectra of magnesium phthalocyanine in different solvents were investigated. The biological activities of 3 and 4 compounds were investigated. The results showed that 4 had excellent antioxidant and antidiabetic activities as 75.71% and 81.83%, respectively. 3 and 4 had deoxyribonucleic acid (DNA) cleavage ability and 4 caused a double-strand fracture in plasmid DNA at 100 and 200 mg/L. Both compounds showed antimicrobial activity and also 4 was more effective against pathogenic microorganisms than 3. Photodynamic antimicrobial therapy of test compound was also more effective than without irradiation. The highest biofilm inhibition of 3 and 4 was 78.28% and 98.49% for S. aureus and also 73.95% and 91.13% for P. aeruginosa, respectively. Finally, both compounds demonstrated %100 microbial cell viability inhibition at 100 mg/L. Overall, the study suggests that both 3 and 4 have potential for further development as therapeutic agents.

Background: The incidence of skin cancer among Danes is one of the highest in the world. Most skin cancers are, however, avoidable with sun protection and reduction of exposure. One way to increase awareness could be through personal biofeedback information about skin DNA damage.

Objective: This study investigates the influence of biofeedback information about skin DNA damage on Danish beach holiday travelers' perception of risk of developing skin cancer and motivations for behaviour change.

Methods: The intervention experiment included 20 participants aged 36-56 years, travelling to destinations with a high UV-index in February/March 2023. A new technology for detecting skin DNA damage in urine was used. Each participant was required to provide urine samples before and after travelling on holiday and participate in an interview about risk perceptions. The interviews were semi-structured and included the disclosure of DNA damage obtained during the holiday. Risk perceptions were assessed using a scale before and after the disclosure of biofeedback information.

Results: We identified key elements affecting perceived susceptibility of skin cancer as well as central barriers for behaviour change. The intervention increased risk perceptions for 35% of participants, and 30% expressed intentions to adopt more sun protective practices. However, most participants' perceived susceptibility to skin cancer did not change significantly, as the DNA damage still appeared too abstract.

Conclusion: The findings suggest that biofeedback information can increase risk perceptions related to skin cancer and initiate intended behaviour change for some. Larger scale studies are needed and should include quantification of the individual DNA damage thereby making the assessed risk more relatable and personally relevant.

Solvatochromism exhibited by azobenzene-4-sulfonyl chloride (here abbreviated as Azo-SCl) has been investigated in a series of non-polar, polar-aprotic and polar-protic solvents. The UV-vis spectra of Azo-SCl exhibit two long-wavelength bands, observed at 321-330 nm (band-I) and 435-461 nm (band-II), which are ascribed to the π*-π (S₂ ← S₀) and π*-n (S₁ ← S₀) transitions, respectively. The shorter wavelength band indicates a reversal in solvatochromism, from negative to positive solvatochromism, for a solvent with a dielectric constant of 32.66 (which is characteristic of methanol), while the longer wavelength band signposts negative solvatochromism in all range of solvent's dielectric constant investigated, demonstrating different interactions with the solvents in the S₂ and S₁ excited states. Using Catalán and Kamlet-Taft solvation energy models, we found that the shift in the solvatochromic behavior of band-I (S₂ ← S₀) happens because solvent dipolarity/polarizability and hydrogen bonding affect the S₂ state in opposite ways. Dipolarity/polarizability stabilizes the S₂ state compared to the ground state, while hydrogen bonding destabilizes it. In contrast, for S₁, both effects work together to destabilize the excited state. For all studied solvents, UV irradiation (λ ≥ 311 nm; room temperature) was found to lead to fast trans-cis azo photoisomerization. In the absence of light, the photogenerated cis form quickly converts back to the trans form. Interpretation of the experimental data is supported by quantum chemical calculations undertaken within the Density Functional Theory (DFT) framework, including Time Dependent DFT calculations for excited states.

β-Nicotinamide mononucleotide (NMN), as a precursor of long-lived protein co-factor nicotinamide adenine dinucleotide (NAD⁺) in the human body, has demonstrated promising clinical value in treating photoaging and skin wounds. Previous research showed that NMN possessed significant skin protection against UVB-induced photoaging and promoted collagen synthesis. However, its potential mechanism remains unclear. This study aimed to investigate whether NMN improved UVB-induced collagen degradation by regulating ROS/MAPK/AP-1 signaling and stimulating mitochondrial proline biosynthesis. The results showed that NMN notably inhibited UVB-induced ROS production and down-regulated the MAPK/AP-1 signaling pathway. In addition, NMN significantly increased proline levels in mitochondria, which acted as the primary raw materials for collagen synthesis. Further mechanistic analysis revealed that NMN increased the levels of mitochondrial NAD⁺ and NADP(H). Besides, NMN supplementation activated pyrroline-5-carboxylatesynthetase (P5CS), a key enzyme in proline biosynthesis, by increasing SIRT3 levels. However, the promoting effects of NMN on proline and collagen synthesis were significantly inhibited when 3-TYP, a SIRT3 inhibitor, was combined applied. Meanwhile, the effects of NMN on collagen synthesis were reversed when the solute carrier family 25 member 51, a mammalian mitochondrial NAD⁺ transporter, was knocked down. Moreover, animal experiments indicated that NMN ameliorated UVB-induced collagen fiber degradation by activating the SIRT3/P5CS signaling. These results revealed that NMN could combat UVB-induced collagen depletion by regulating the ROS/MAPK/AP-1 and proline synthesis.