Photochemistry and Photobiology最新文献

Within the ultraviolet C (UVC) spectrum, the wavelengths in the 200-235 nm range, here named far-UVC, have been shown to effectively inactivate a variety of pathogens. Because of their limited penetration in biological materials, far-UVC wavelengths are anticipated to be minimally damaging to human skin and eyes. The germicidal efficacy of these wavelengths combined with a predicted low health hazard for humans suggests that far-UVC sources could operate continuously in indoor locations to reduce the risk of transmission of airborne diseases among occupants. While it is well-established that exposure to far-UVC light is minimally damaging to skin, concerns remain on the safety of exposed eyes. Scientific bodies overseeing UV radiation protection recommend eye safety limits based on published peer-reviewed data. To support this goal, our previous work used a 3D model of the human cornea to assess the wavelength dependence of corneal damage induced by UVC radiation; unlike relatively longer wavelengths, far-UVC wavelengths induced DNA dimers only in the uppermost layers of the corneal epithelium. Here, similar eye safety studies were extended to excised human corneas. The depth of DNA photodamage into the corneal epithelium was evaluated after exposure of the anterior surface to 50 mJ/cm² or 100 mJ/cm² from 222 nm or 254 nm light.

Skeletal muscle injury is a common sports injury and photobiomodulation (PBM) therapy has been recognized as a potential treatment for it. However, the optimal intervention timing for PBM to suppress inflammatory factor expression during muscle regeneration remains unclear. The study is a systematic review with meta-analysis to summarize the effect of PBM on the expression levels of inflammatory factors during skeletal muscle regeneration in animals. The PubMed, Cochrane Library, Scopus, and Web of Science databases were searched to obtain the studies about the effects of PBM on the inflammatory factors during muscle regeneration in animals. Two authors independently extracted the data, and the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) tool was used to assess the risk of bias for the included studies. Review manager 5.4 software was used to analyze the data, and subgroup and sensitivity analyses were performed. A total of 18 studies were included in this study. The results show that PBM treatment reduces levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 during skeletal muscle regeneration, especially in the early stage of skeletal muscle injury (6 and 12 h), but its effects on IL-4 and IL-10 need to be validated in higher-quality studies. In conclusion, PBM therapy primarily reduces inflammatory factor levels in the early stage of skeletal muscle injury, thereby accelerating skeletal muscle regeneration.

In this work, the potential synergistic antineoplastic activity of tetrahydroxyquinone (THQ) in combination with photothermal therapy using gold nanoshells (AuNSHs) as photosensitizers and applying NIR light at 808 nm has been analyzed. To synthesize the AuNSHs, a core of PLGA and PVA was coated with oligochitosan, which was then mixed with a solution of gold seeds. The core-shell particles were obtained by a seeded-growth process in the presence of K-gold and ascorbic acid. These gold structures underwent an Ostwald ripening process and were subsequently PEGylated to increase their biocompatibility and colloidal stability. The diameter of these AuNSHs has an average of 131 ± 10 nm, a zeta potential of -20 ± 1 mV at physiological pH, a hydrodynamic diameter of 188 ± 2 nm, and a power absorption density of up to 93 W/cm³. Cell biology assays, using BT-474 breast cancer cell line, revealed a negligible decrease in metabolic activity when the cells were exposed to up to 1 mg/mL AuNSH, 100 μg/mL THQ or were irradiated for 15 min with an optical power (OP) of 2.0 W. The simultaneous administration of 1 mg/mL AuNSH and 100 μg/mL THQ reduced the cell viability only by ~17%. However, when following a photothermal therapy (AuNSH irradiated an OP of 2.0 W), 100 μg/mL THQ were added to the cells, their viability decreased significantly by ~61%, indicating a synergistic effect of the treatment. Using the Annexin V assay, it could be revealed that the majority of cells underwent apoptosis and only few died by necrosis.

The increasing incidence of skin cancer, including melanoma, combined with the need for ultraviolet (UV) filters that are safe for human health and marine ecosystems, is driving the search for new photoprotective agents. Gadusol, a natural metabolite present in marine organisms, has been identified as a compound capable of absorbing UV radiation and exerting antioxidant functions. In this study, we investigated the photoprotective effects of gadusol on non-tumorigenic murine melanocyte cell line exposed to UVB radiation. Cell viability was assessed by trypan blue exclusion, and parameters of cell death, reactive oxygen species (ROS) generation, and proliferation were also analyzed. The results showed that gadusol (50 μM) did not exhibit cytotoxicity and, when administered during exposure to 15 and 30 mJ/cm² of UVB, protected cells against reduced cell viability and viable cell count. Furthermore, gadusol also protected against apoptosis, attenuated ROS production, and maintained the proliferative rate at levels similar to the control, even under high UVB doses (30 mJ/cm²). We conclude that gadusol exerts effective photoprotective action, attenuating the effects of UVB radiation on melanocytes without compromising cell viability or proliferation. These findings reinforce the potential of gadusol as a safe, effective, and environmentally sustainable alternative for skin photoprotection applications.

Excessive exposure to ultraviolet (UV) radiation poses significant public health risks, including DNA damage and skin-related pathologies. This necessitates accurate studies and quantification of UV-radiation exposure. Various wearable UV dosimeters have been developed to address these needs, particularly for outdoor workers. For measuring erythemal irradiance, recommendations from the World Meteorological Organization exist but standardized methods for characterization and calibration of wearable UV dosimeters are currently limited. At Aalto University and at Physikalisch-Meteorologisches Observatorium Davos, three commercial electronic UV dosimeters were evaluated for their spectral responsivities using conventional measurement methods and traceability chains. The first device closely mimicked erythemal action in UV-A and UV-B regions. Two of the measured devices were found to have a higher relative responsivity of over 0.9 in the 300 nm to 310 nm range. Results were used to calculate correction factors for measuring erythemal radiance at varying solar zenith angles and ozone levels under cloud-free conditions. Typical correction factors ranged from 0.98 to 1.2. The results of the two laboratories were in good agreement for the most accurate device but deviated due to the properties of the two other devices. The measurements revealed challenges posed by these devices in terms of data management, measurement times, and deployment, highlighting the need for standardized characterization methods.

The ultraviolet (UV) radiation environment consists of direct UV and diffuse UV components. The ratios of diffuse-to-direct UV for the UVB, UVA, and the erythema UV wavebands are influenced by clouds, aerosols, albedo, and surface reflectance, Rayleigh scattering, and solar zenith angle. At times, the relative proportion of diffuse UV may be higher than the direct UV, for example, on cloudy days or days with high atmospheric aerosols. Consequently, exposures due to diffuse UV radiation play a significant role in the UV exposure received by human subjects. Diffuse UV radiation contributes to the risk of skin cancer and sun-related eye disorders. Reducing personal exposure to diffuse UV by physical protection, including tree shade, purpose-built shade structures, protection by hats, and eyewear, is more difficult than reducing direct UV exposure due to the diffuse UV being incident from all directions. The UV index reported to the public represents the sum of the direct and the diffuse erythema UV, with no information provided specifically on the diffuse UV component. This paper reviews the factors that contribute to diffuse UV exposures affecting human populations. It examines diffuse UV modeling techniques, and broadband and spectral component measurements.

We have investigated the photosensitized generation of singlet oxygen (¹Δ_g) from a variety of diones derived from benzo[a]pyrene (1), namely benzo[a]pyrene (6,12) dione (2), benzo[a]pyrene (1,6) dione (3), benzo[a]pyrene (3,6) dione (4), and benzo[a]pyrene (4,5) dione (5). The diones 2-4 are formed in the atmosphere as secondary photoproducts from benzo[a]pyrene. Benzo[a]pyrene (4,5) dione (5) was additionally selected for this study due to its much larger dipole moment relative to the other diones. All of these diones are excellent sensitizers with quantum yields of singlet oxygen generation (Φ_Δ) ranging from 0.77 to near unity. Singlet oxygen appears to be generated primarily from the triplet excited state. Quantum yields were measured in four solvents with different polarity. The singlet oxygen quantum yield for benzo[a]pyrene decreases with increasing polarity of the solvent. By contrast, the values for Φ_Δ for the diones 2-5 increase slightly with increasing polarity of the solvent. Unlike substituted anthracene derivatives, all of the diones 2-5 show very little singlet oxygen quenching, as singlet oxygen lifetimes showed no decrease compared with the literature values when diones 2-5 were used for singlet oxygen generation. The large singlet oxygen quantum yields for diones 2-5, and the lack of singlet oxygen quenching implies that, in the presence of these compounds in the environment, photosensitized generation of singlet oxygen generation could be significant.

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) cause severe photosensitivity, resulting in significant quality of life (QoL) impairment. This study aims to evaluate the safety and efficacy of Polypodium leucotomos extract (PLE) as an adjunctive therapy in patients with persistent symptoms despite standard dosing of afamelanotide. In this prospective single-center cohort study, eight adults with confirmed EPP or XLP and ongoing symptoms despite regular afamelanotide implants every 2 months were enrolled. Participants received 480 mg oral PLE daily for 4 months. QoL and symptom severity were measured using questionnaires at baseline, Day 60, and Day 120. Six participants completed the study. Statistically significant improvements in QoL were observed on Day 60 (p = 0.014), but not at Day 120 (p = 0.152). Half of participants reported reduced reaction severity. No adverse events occurred. Adjunctive PLE improved short-term QoL in participants with incomplete symptom control on afamelanotide alone and was well tolerated. Larger studies are warranted.

Up to 80%-90% of recurrent peritoneal metastasis cases exhibit resistance to multiple chemotherapy agents. A major contributor to this multidrug resistance is the active efflux of chemotherapeutics by P-glycoprotein (P-gp), also known as ATP-binding cassette subfamily B member 1 (ABCB1) transporter and multidrug resistance protein 1 (MDR1). Clinical attempts to inhibit P-gp using small molecule inhibitors have been limited by systemic toxicity or poor tumor selectivity, underscoring the need for safer, targeted strategies. To address this challenge, we demonstrated, for the first time, that intraperitoneal photoimmunotherapy (PIT) using a photoimmunoconjugate (PIC) can inhibit the function of P-gp in a mouse model of peritoneal carcinomatosis. PIC was synthesized and characterized, and a sterile filtration protocol was implemented for its in vivo administration and intraperitoneal PIT application. To assess P-gp function following low-dose PIT, in vivo tumor cells were isolated and evaluated for intracellular accumulation of a well-established P-gp substrate (Rhodamine 123). PIC-PIT significantly increased intracellular Rhodamine 123 retention, indicating effective reduction of P-gp activity. This study provides the first in vivo evidence that PIT can inhibit P-gp function, offering a promising, targeted approach to overcoming chemoresistance while avoiding the systemic toxicity associated with conventional P-gp inhibitors.

Gaussia luciferase (GLase) is a secreted enzyme composed of 168 amino acids, including 10 cysteine residues, and catalyzes the oxidation of coelenterazine to emit light. To evaluate the disulfide bond positions in GLase, we generated 10 cysteine-to-serine substituted GLase genes, in which each cysteine residue was replaced with a serine residue (C52S, C56S, C59S, C65S, C77S, C120S, C123S, C127S, C136S, and C148S), using site-directed mutagenesis. In both bacterial and mammalian expression systems, four disulfide bonds formed between eight cysteine residues (C52, C56, C65, C77, C123, C127, C136, and C148) were found to be essential for luminescence activity. In bacterial cells, the single mutants C59S and C120S, as well as the double mutant C59S/C120S, exhibited luminescence activities of 258%, 2.8%, and 42.8%, respectively, relative to wild-type GLase (100%). Notably, all three mutants could be efficiently refolded by dialysis after treatment with 2-mercaptoethanol. In mammalian cells, only the double mutant C59S/C120S was secreted and showed luminescence activity of 11% in the culture medium, relative to wild-type GLase (100%). By integrating previously reported NMR-based structural data of recombinant GLase purified from bacterial cells with our experimental findings, we conclude that GLase contains five disulfide bonds: C52-C127, C56-C123, C59-C120, C65-C77, and C136-C148, which are consistent with those reported in PDB ID: 7D2O.