Photochemistry and Photobiology最新文献

Photocatalytic CO₂ fixation into solar fuels offers a promising route for renewable energy storage by converting CO₂ into chemical bonds. Among various products, formic acid is considered the most reliable candidate for industrial applications due to its high efficiency and sustainable feasibility. Various catalysts, including metals, chalcogenides, transition metals, and carbon-based materials, have been explored for this purpose. Polymeric organic frameworks are a class of crystalline polymers with tunable structures, making them potential candidates for metal-free photocatalysts. However, their low crystallinity often limits light-harvesting efficiency and photocatalytic activity, posing a challenge for industrial applications. The primary obstacles in this field are low activity and poor selectivity of photocatalysts. In this study, we propose a soft-template induction strategy to construct a metal-free heterojunction polymeric framework based on 5,15-di-(4-aminophenyl)-10,20-diphenyl porphyrin (BP) and perylene tetra-anhydride (PT), referred to as PTBP. This polymer exhibits high crystallinity and strong solar light absorption. The PTBP framework demonstrates better performance in solar-powered molecular artificial photosynthesis, achieving significant improvements over PT. Specifically, PTBP exhibits high 1,4-NADH/NADPH regeneration efficiencies (52.51%/58.41%) compared to PT (9.11%/10.1%), a substantial NADH consumption (119.25 μmol) in exclusive solar fuel production from CO₂ within 1 h, and excellent yield (50.37%) in the photocatalytic conversion of dopamine into an indole-derivative, surpassing PT (13.93%). The current finding highlights the benchmark photocatalytic potential of the PTBP polymeric framework's capacity for photocatalysis for CO₂ fixation and conversion of dopamine into indole derivatives.

In this study, a highly sensitive, cost-effective, and environmentally friendly fluorescent sensing platform is presented for the rapid detection of pyrene (PYR), a polycyclic aromatic hydrocarbon (PAH), by leveraging the optical properties of the plant pigment chlorophyll (Chl). The detection mechanism relies on monitoring changes in Chl's photoluminescence (PL) intensity, fluorescence lifetime, and Fourier-transform infrared spectra. An impressive detection limit of 0.25 picomolar was achieved, surpassing the sensitivity reported in many previous studies. Fluorescence resonance energy transfer (FRET) was identified as the primary mechanism underlying the observed sensing response. The platform's effectiveness was further validated using soil and water sediment samples collected from oil exploration sites, demonstrating reliable quantification of PYR. This research underscores the potential of Chl-based fluorescence as a sustainable and efficient tool for a wide range of sensing applications, particularly in environmental monitoring.

Antibacterial photodynamic therapy (aPDT) is a promising approach for inactivation of antibiotic-resistant bacteria; however, its effectiveness is compromised, particularly when bacteria hide within biofilm and if infection spreads deeper in tissue. To overcome this limitation, photosensitizers having absorption in the near-infrared region (NIR) (650-800 nm), where light penetrates deeper in tissue, need to be developed. We report aPDT efficacy of Cycloimide Purpurin-18 betaine hydrazide conjugate (CIPp-18-BH), a cationic chlorophyll derivative, against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO). CIPp-18-BH was synthesized by conjugating CIPp-18 to betaine hydrazide (BH) using a carbodiimide coupling reaction. CIPp-18-BH, as compared to CIPp-18, exhibited lower lipophilicity; thereby, it did not aggregate in aqueous conditions and generated a substantial amount of singlet oxygen upon photo-excitation with red light. CIPp-18-BH exhibited no fluorescence in water and substantial fluorescence in less polar solvents. CIPp-18-BH bound to planktonic bacteria did not show fluorescence; whereas remarkable fluorescence was seen in biofilms, indicating it lies on the surface of bacteria and accumulates within the apolar micro-environment of biofilms. PDT of planktonic MRSA and PAO with 40 μM CIPp-18-BH led to ~7 log and ~2.5 log reduction in cell viability, respectively. Confocal microscopy showed that PDT led to substantial bacterial inactivation within MRSA and PAO biofilms, resulting in inhibition of biofilm growth by ~50% and ~20%, respectively. Results demonstrate that CIPp-18-BH is a promising photosensitizer for photodynamic inactivation of planktonic and biofilm-borne bacteria.

"Photochemistry and Photobiology," currently part of Wiley-Blackwell edition group is the official Journal of the American Society for Photobiology. The Journal is a suitable platform for the publication of scientific information on a wide range of domains of Photosciences spanning from photophysical and photochemical events to biological consequences. In addition to regular contributions, essentially original research and review articles, special issues are published on invitation. This covers various subjects including survey of timely topics, outstanding scientist recognition and celebration of scientific events. The Editorial Board composed of 32 internationally recognized experts plays a major role in handling fairly and rigorously the peer-review of the manuscripts with the efficient support of the Managing Editor. Importantly Wiley has recently implemented an improved manuscript submission system together with a more attractive format for the published articles. These suitable conditions should favor the submission of manuscripts and help to consolidate/improve the attractiveness of the Journal.

Nonmelanoma skin cancers are rising in incidence and are largely driven by solar ultraviolet B radiation (UVB) exposure. A growing body of evidence suggests that m⁶A RNA methylation plays a critical role in regulating the DNA damage response to UVB. Here, we identify a novel function for the m⁶A demethylase FTO in modulating the UVB damage response and skin carcinogenesis. We show that FTO loss enhances the repair of cyclobutane pyrimidine dimers (CPD), the major DNA lesions induced by UV radiation, in a METTL14-dependent manner, at least in part by promoting protein translation of the global genome repair (GGR) factor DDB2 through increased m⁶A methylation of DDB2 mRNA. These effects were recapitulated using two small-molecule FTO inhibitors, CS1 and FB23-2. Furthermore, loss of FTO reduced tumor growth in mice and FTO expression was upregulated in cutaneous squamous cell carcinoma (cSCC) compared with normal skin. Together, these findings uncover a critical role for FTO in regulating post-transcriptional gene expression in the UVB damage response and suggest that FTO may be a therapeutic target in skin cancer.

The increasing contamination of aquatic systems by synthetic dyes such as methylene blue (MB) underscores the urgent need for sustainable and cost-effective wastewater treatment technologies. In this study, a novel biocomposite photocatalyst composed of chitosan and thermally treated ZSM-5 zeolite, denoted as ZSM-5 (800)/CS, was synthesized and systematically evaluated for its environmental remediation potential. The ZSM-5 (800)/CS composite exhibited superior photocatalytic activity, achieving 63% MB degradation within 210 min-significantly higher than pure chitosan, which achieved only 21% removal under identical conditions. The reduced optical bandgap (2.24 eV) of the biocomposite enhanced visible-light absorption, thereby improving its photocatalytic performance. Moreover, under aerobic conditions, ZSM-5 (800)/CS demonstrated excellent catalytic efficiency for the selective oxidation of organic sulfides to sulfoxides, achieving up to 96% yield and selectivity. These results highlight the dual functionality of the biocomposite for both wastewater detoxification and valuable chemical transformation. The study emphasizes the potential of integrating biopolymeric and zeolitic frameworks to develop sustainable photocatalysts that contribute to cleaner water resources and greener environmental technologies.

6-Thioguanine (6-TGua) is one of the thiopurines used as a cytostatic drug. When internalized by cells, 6-TGua is metabolized through the purine salvage pathway and readily incorporated into DNA. Patients treated with these thiopurines are more prone to develop squamous cell carcinoma of the skin. The absorbance spectrum of 6-TGua, in contrast to guanine (Gua) or any other canonical base, has a maximum absorbance at 342 nm. Therefore, 6-TGua undergoes photoexcitation upon exposure to UVA radiation, with maximum absorption at 340 nm. In this study, the used approach unequivocally demonstrates the generation and quenching of ¹O₂ by 6-TGua via the direct spectroscopic detection of ¹O₂ monomol light emission at 1270 nm. Chemiluminescence-based methods were employed for the determination of the ¹O₂ generation quantum yield (Φ¹O₂) and the total ¹O₂ quenching rate constant (k_t). For the ¹O₂ quantum yield, we found values of 0.22 ± 0.03 for 6-TGua and 0.12 ± 0.03 for 2'-deoxy-6-thioguanosine (6-TdGuo). These compounds presented k_t values of 1.5 × 10⁷ L mol^-1 s^-1 and 1.1 × 10⁷ L mol^-1 s^-1, respectively. Through the comparison of these values with the ones obtained for 2'-deoxyguanosine (dGuo) and its oxidation product 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), we aim to provide new insights into the 6-TGua-containing DNA (DNA-6-TGua) reactivity towards ¹O₂ in a biological context.

Previous murine studies have implicated acid sphingomyelinase (aSMase)-generated subcellular microvesicle particles (MVP) in photosensitivity. Objective: The current double-blinded placebo-controlled studies examined if a single localized ultraviolet B radiation (UVB) treatment generated more MVP in human subjects with self-identified photosensitivity versus normal controls. A topical 4% formulation of the aSMase inhibitor imipramine applied immediately after UVB blocked the MVP release and erythema responses. Erythema responses at 24 and 72 h in response to multiple UVB fluences and minimal erythema doses (MED) at 24 h and effects of imipramine were also tested. Small cohorts of 10 adult self-identified photosensitive subjects and 12 controls were enrolled in these pilot studies which revealed increased levels of skin MVP in UVB-treated photosensitive subjects over controls which correlated with MED values. Moreover, post-UVB application of imipramine blunted UVB-induced MVP responses as well as tended to diminish erythema levels at 4 h but not at 24 or 72 h in photosensitive patients. Though limited by low numbers of self-identified subjects, these pilot studies provide some support for the hypothesis that MVP could be involved in multiple types of human photosensitivity responses and suggest aSMase inhibition as a potential therapeutic strategy.

The in vivo transcriptional response of mouse skin to ultraviolet radiation (UV-R) exposure reveals key genomic alterations associated with UV-R-induced damage but it does not provide precise dose thresholds for these effects. These initial findings provided the impetus to advance dose-response characterization by integrating benchmark dose (BMD) modeling with transcriptomic data, aiming to identify biologically relevant points of departure for gene and pathway activation. To accomplish this, mice were exposed to five erythemally weighted UV-R doses (0-40 mJ/cm²) emitted from a UV-emitting tanning device, across six post-exposure timepoints (0-96 h). Four analytical methods were used to estimate BMDs, with the lowest consistent response dose (LCRD) approach yielding the most sensitive estimates (1.21-3.44 mJ/cm²). Transcriptomic responses revealed activation of shared pathways related to DNA damage and cancer, oxidative stress and metabolism, inflammation and immunity, and hormonal disruption. Notably, the majority of LCRD BMD estimates (1.21-3.44 mJ/cm²) were lower than the International Electrotechnical Commission standard actinic exposure limit (3 mJ/cm² (erythemally weighted)) for broadband UV-R (200-400 nm) for unprotected skin and the eye for an 8 h period. These findings suggest that transcriptomic BMD modeling can detect early biological responses to UV-R at doses lower than current exposure limits.