The determination of the sun protection factor (SPF) remains a complex and resource-intensive task, motivating the development of alternative approaches. In this study, a chemometric-assisted strategy for SPF classification based on in vitro UV spectral data is proposed. UV absorbance spectra were obtained according to ISO 24443:2012 and analyzed using self-organizing maps (SOM) and principal component analysis (PCA). Classification models were developed using partialleast squares discriminant analysis (PLS-DA). The exploratory analysis indicated that spectral variations, mainly associated with absorbance intensity in the 290–340 nm region, are relevant for distinguishing SPF classes (15, 30, and 50). The PLS-DA models achieved classification rates of 93
Mesenchymal stem cell-secreted paracrine factors, especially exosome, has emerged as promising therapeutic candidates for mitigating UVB-induced cutaneous photodamage. While adipose-derived stem cell exosome (ADSCs-Exo) are well documented to alleviate UVB-triggered DNA damage, the precise molecular mechanisms underlying this effect remain poorly elucidated. Herein, we illustrated that ADSCs-Exo drastically curbed UVB-elicited cellular apoptosis, cell cycle arrest, comet tail formation, γH2AX foci accumulation, and cyclobutane pyrimidine dimer deposition in HaCaT keratinocytes. Consistent with the in vitro findings, ADSCs-Exo substantially mitigated cutaneous DNA damage and skin cell apoptosis in UVB-exposed Kunming mice. Notably, pharmacological autophagy blockade using 3-methyladenine effectively abolished these ADSCs-Exo-dependent protective outcomes. Mechanistically, ADSCs-Exo treatment facilitated the degradation of core autophagy receptors, including p62, NBR1, and TAX1BP1. Subsequent functional validation assays identified ectopic p62 overexpression as the sole manipulation capable of counteracting ADSCs-Exo's cytoprotective potency. Co-immunoprecipitation assays further verified a direct interaction between p62 and the E3 ubiquitin ligase RNF168. P62 overexpression hindered RNF168 recruitment to DNA lesion sites, accompanied by suppressed histone K63-linked polyubiquitination and H2AX ubiquitination, as well as impaired recruitment of the DNA damage repair factors BRCA1 and RAD51. Furthermore, genetic knockdown of RNF168 markedly diminished histone H2AX ubiquitination and compromised the protective functions of ADSCs-Exo. Collectively, this study uncovered a novel autophagy-dependent p62-RNF168 regulatory axis governing ADSCs-Exo-mediated photoprotection, providing a promising therapeutic strategy for ultraviolet-associated skin DNA damage and photocarcinogenesis.
The integration of photosensitization with Indigenous knowledge offers a promising framework for exploring more sustainable therapeutic approaches. This review explores how the ethnobotanical knowledge of the Dayak communities of Borneo (Indonesia), particularly the traditional use of brightly coloured medicinal plants for dermatological treatments, may provide a biologically informed framework for prioritizing plant-derived photosensitizer candidates. The biosynthetic pathways and photochemical potential of key metabolites associated with selected Dayak medicinal taxa (Curcuma longa, Etlingera elatior, Calophyllum inophyllum, Ageratum conyzoides, and other selected additional representatives of the Zingiberaceae family) are analyzed to assess their potential as light-activated ROS generators. In addition, the review discusses strategies to optimize the production and delivery of promising plant-derived candidates through metabolic engineering, including heterologous expression in microbial chassis such as Escherichia coli and Saccharomyces cerevisiae. A comparative evaluation based on green chemistry principles suggests that plant-derived candidates may offer potential advantages related to renewable sourcing, although their biodegradability, safety, and overall environmental performance remain insufficiently characterised. Finally, the review outlines an ethical framework for integrating Dayak traditional knowledge into scientific research while promoting equitable benefit-sharing and biocultural protection. Overall, this work proposes a transdisciplinary perspective for photomedicine in which ethnobotanical knowledge, photochemistry, and sustainable biotechnology converge to guide the identification, evaluation, and development of plant-derived photosensitizer candidates.
Photodynamic Therapy (PDT) is a therapeutic approach for several cancer types based on the photoactivation of photosensitizer (PS), leading to reactive oxygen species (ROS) generation and cancer cell death. Given that autophagy may exert cytoprotective or cytotoxic effects following PDT, modulation of autophagy-related pathways has attracted increasing research interest for improving therapeutic outcome. In this study, newly synthesized carbon dots (CDs) and commercially available aluminum chloride phthalocyanine (AlClPc) were employed as PSs individually or in combination with the autophagy-inducer monocarbonyl curcumin analogue C1 under different treatment protocols. CDs were synthesized based on a facile hydrothermal technique and characterized for their morphological, chemical, physicochemical and optical properties, showing intense blue fluorescence, and pronounced ROS generation ability. PDT studies revealed moderate light dose-dependent phototoxicity for CDs, whereas AlClPc presented significantly enhanced photodynamic activity. To investigate the influence of autophagy modulation on PDT response, pre-treatment, post-treatment, and co-incubation protocols with C1 were employed under 661 nm irradiation. Pre-treatment with C1 enhanced the PDT efficacy of CDs, while post-treatment and co-incubation protocols attenuated CDs-mediated phototoxicity, indicating a cytoprotective effect of C1. In contrast, all C1-containing treatment protocols improved the photodynamic performance of AlClPc. ROS generation studies further supported the observed biological responses. The present study highlights the dual role of autophagy modulation in PDT and demonstrates that C1 may either attenuate residual phototoxicity following CDs-mediated PDT or enhance the photodynamic efficacy of AlClPc, depending on the PS. These findings emphasize the potential of autophagy-related strategies for the optimization of PDT applications.
The repair of photo-induced DNA lesions through nucleotide excision repair machinery is still the source of important questions. It has been observed that the repair rate of the different cyclobutane pyrimidine dimers, i.e. the photoproducts induced by dimerization of two π-stacked pyrimidines (T < > T, T < > C, C < > T, C < > C), depends on the nucleobases involved in the lesion. TT derivatives (T < > T) are removed more slowly than those containing cytosine, especially in 5'. Using all-atom molecular dynamics simulations, we demonstrate that the variation of the repair rate observed in human skin and in cultured cutaneous cell may be associated to the recognition of the four lesions by the DDB2 protein moiety, and more specifically by the differential structural deformation induced on the complementary strand and the major groove. These effects may then hamper differentially the downstream recruitment of the repair complexes. The observed DNA deformation correlates with the experimental repair rate and suggests a structural rationale for the different repair rates of CPD by nucleotide excision repair machinery.
Peroxynitrite (ONOO⁻) is a crucial physiological and pathological mediator, yet its highly selective detection in complex biological environments remains a demanding analytical task. To address this, we developed DE-P, a triple-reaction-based, dual-emission “Off-On” fluorescent probe designed to achieve high selectivity by integrating naphthalimide and hemicyanine scaffolds. DE-P is initially non-fluorescent. However, upon interaction with ONOO⁻, it undergoes a specific reaction cascade involving three transformations: the cleavage of the trifluoromethanesulfonate group, the oxidative decomposition of the hemicyanine core, and the oxidation of the thiomorpholine moiety. Consequently, distinct dual-emission signals are triggered at 467 nm and 567 nm, providing a broad spectral gap of approximately 100 nm. This triple-reactive design enables sensitive trace-level detection (limits of detection: 0.12 and 0.19 µM) and fluorescence across a wide pH range (3–10), providing high selectivity for ONOO⁻ over competing reactive species (ROS/RNS) and common biological interferents. Elucidated through comprehensive spectroscopic and mass spectrometric analyses, the sensing mechanism of DE-P establishes it as a promising chemical tool for the reliable tracking of ONOO⁻ in biological and environmental samples.
Host-guest chemistry has witnessed a renaissance under the name 'supramolecular chemistry' since the award of Nobel Prize to Cram, Lehn and Pederson in 1987. During the last five decades, threading several concepts of host-guest chemistry and physical organic chemistry that have existed for over a century, 'supramolecular chemistry' has enabled altering the chemical and physical behavior of molecules, not only in the ground but also in the excited state. One of the problems of this approach is that most common host systems are 'porous (partially open)' resulting in reactions occurring both within and outside the host in organic solvents, leading to poor selectivity. Given the current thrust on performing molecular transformations under environmentally friendly and sustainable conditions, light as a reagent and water as the medium is a good approach. Water insolubility and porosity in host-guest complexes could be overcome with a water-soluble host that fully surrounds the reactant molecule. In this context, octa acid (OA) that is water soluble and forms a closed capsule by including organic guest molecules within it is noteworthy. One of the drawbacks of confining a molecule is that it loses its freedom to interact with other molecules in solution. In this Perspective using OA as the host, we provide examples where the confined molecules are able to communicate with free unconfined molecules in water leading to spin, electron and energy transfer. The proof of principle established here should work with even larger capsules when they become available.
Afamelanotide, an analogue of α-melanocyte stimulating hormone, activates the melanocortin-1 receptor and has a range of protective properties as demonstrated largely in vitro. While afamelanotide is approved to treat a visible light-induced inflammatory dermatosis, erythropoetic protoporphyria, its acute effects in vivo are poorly characterised. We explored short-term effects of afamelanotide on the acute inflammatory response of UVR-induced erythema and on the melanogenic response, in healthy humans. Participants (n = 9, 5 M:4 F, 27-43y, phototypes II-III) had melanin density and skin lightness measured at six skin sites using spectrophotometry. A broadband UVB dose-series (7–80 mJ/cm2 erythemally-weighted UVR, Philips TL12) was applied to buttock skin. After 24 h, minimal erythema dose (MED) was assessed, spectrophotometric measurements were taken of erythema at each dose site and two unexposed sites, and an unexposed site was biopsied. Afamelanotide was administered (16 mg subcutaneous implant) and after six days the same UVR dose-series applied to contralateral buttock skin, and measurements and biopsy repeated. Melanin was stained in biopsy sections (modified Warthin-Starry method) and quantified by image analysis. The UVR-erythema dose response (area-under-curve) decreased post-afamelanotide (mean 3.5 pre, 2.7 post, P = 0.018) with an apparent increase in MED (median 21 mJ/cm2 pre, 29.9 post, not sign.). Melanin density (reflectance at 420 and 400 nm) increased (mean overall increase 2.4
This study combines experimental and theoretical methods to explore the photochemical stability of progestins in a climate-sensitive model system for urban reservoirs worldwide, with a focus on the Guarapiranga Reservoir in São Paulo, Brazil. The target contaminants were levonorgestrel (LNG) and gestodene (GES), synthetic progestins used in contraceptive methods. Photoinduced reaction kinetics showed that LNG’s indirect photolysis is affected by triplet excited states of chromophoric dissolved organic matter (3CDOM*), hydroxyl radicals (HO·), and singlet oxygen (1O2), in the order 3CDOM* > HO· > 1O2. Conversely, for GES, the sequence was HO· ≈ 3CDOM* > 1O2. Water quality data from 2022 to 2024, along with kinetic modeling, estimated half-lives of 6.9 ± 1.2 days for LNG and 25.8 ± 9.0 days for GES. Density Functional Theory (DFT) analysis identified key reactive sites and degradation pathways, aligning well with experimental results. An ecotoxicological assessment of the photo intermediates using the ECOSAR model showed notable toxicity to daphnia, fish, and green algae, especially after the addition of HO· radicals. These findings offer valuable insights into the environmental fate of LNG and GES in urban surface waters and contribute scientific evidence to decision-making on monitoring and removing emerging contaminants through advanced wastewater treatment technologies.
Octa-coordinated Eu(III) complexes were synthesized via the solution precipitation method. The synthesized complexes were characterized through elemental analysis, UV analysis, XRD, SEM, FTIR, 1H-NMR, TGA/DTA and photoluminescence analysis. IR and NMR analyses show that ligand coordinates through oxygen atom of aldehydic, oxygen atom of ketonic groups and nitrogen atom of ancillary ligand. The band gap energies obtained from reflectance measurements ranges (2.19–2.52 eV) and are in close agreement with computational analyses (2.20–2.54 eV). Photoluminescence spectroscopy conducted in both phases (solution and solid) shows red emission with five distinct emission peaks, among these 5D0 → 7F2 transition is the most intense transition. The J-O parameters, luminescence decay time, radiative and non-radiative decay rates, as well as quantum efficiencies, were calculated to elucidate the optical properties of complexes. Color purity (CP) values of complexes in solution ranges from 82.87
Hypertension is the leading global risk factor for cardiovascular disease. Ultraviolet (UV) radiation exposure has been proposed as a potential modifiable environmental factor influencing blood pressure regulation. While traditionally associated with vitamin D synthesis, emerging evidence suggests alternative mechanisms, including nitric oxide (NO) mobilization, may play a significant role. To systematically review the available evidence on effects of UV exposure on blood pressure, with a focus on hypertension in human populations. A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases were searched for studies investigating the impact of UV exposure (UVA and/or UVB) on blood pressure. Eligible studies included randomized controlled trials (RCTs), clinical trials, and observational studies involving human participants. Data extraction and risk of bias assessment were performed independently. A total of 14 studies were included in the final analysis. The majority demonstrated that UV exposure, particularly UVA, was associated with a reduction in blood pressure. Several studies suggested that this effect is mediated through NO release from cutaneous stores, independent of vitamin D pathways. However, findings were heterogeneous, with studies reporting no significant effects, likely due to differences in study design, population characteristics, and exposure protocols. UV exposure, especially UVA, demonstrates a blood pressure-lowering effect, potentially mediated by NO-related mechanisms. However, clinical translation requires a balanced quantitative risk-benefit assessment that considers potential cardiovascular benefits, all-cause mortality-related evidence, and dermatological risks. Further large-scale and well-designed RCTs with standardized exposure protocols and long-term safety follow-up are required before UV-based interventions can be recommended for cardiovascular prevention or hypertension management.
Chiral recognition between adenosine and amino acids was investigated by ultraviolet photodissociation spectroscopy of hydrogen-bonded protonated clusters at 8 K in the gas phase. The S1–S0 transitions of protonated adenosine hydrogen-bonded with lysine, glutamine, and glutamic acid were redshifted compared to that of adenosine hydrogen-bonded with protonated arginine, indicating that protonation on adenosine caused the redshift. The relative intensity of the band at 280–285 nm of protonated adenosine hydrogen-bonded with d-glutamic acid was approximately twice that of l-glutamic acid. The enantiomers of glutamic acid and glutamine were differentiated by the spectra, but the enantiomers of arginine and lysine could not be differentiated. The protonation site of amino acids required for chiral recognition by adenosine was the α-amino group.
The effects of different π-conjugation extension modes on the photophysical properties and excited state intramolecular proton transfer (ESIPT) behavior were systematically explored via density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. It can be clearly found that the intramolecular hydrogen bonds (IHBs) become stronger upon photoexcitation, which is favorable to the ESIPT process. However, all π-conjugation extension modes weaken the IHB, and then hinder the ESIPT process, but the degree of inhibition of ESIPT varies with different π-conjugation expansion modes. Fused naphthalene ring has a more significant inhibitory effect on ESIPT process. Furthermore, the fused naphthalene ring results in a more pronounced red shift of the enol and keto fluorescence peaks compared to the fused benzene ring. While at the same fused ring, the π-conjugation extension at the 2,3- and 1,2-position causes the fluorescence peak to shift the most and the least towards the red, respectively.
Significant trends of ultraviolet radiation (UVR) have been reported at limited European sites due to changing atmospheric conditions, such as cloudiness. Whether these findings are applicable to larger areas or even the entire continent remains unclear. In a unique comparison, we analyzed measurements of erythemally weighted daily ambient radiant exposure from 40 European locations, covering the period from 2013 to 2022. At 26 locations annual means increases statistically significantly with a median of + 1.2
The present study reports the synthesis and evaluation of photoluminescent properties of a novel Aggregation Induced Emission (AIE) and Excited State Intramolecular Proton Transfer (ESIPT) active Schiff’s base (E)-N’-(3,5-dibromo-2-hydroxybenzylidene)-4-methylbenzenesulfonohydrazide (MATS) which was found to fluoresce in solution and solid state. The probe molecule was synthesized using various methods including conventional, solvent free and mechanochemical means, which rendered the product in good yields. The AIE properties of the probe was utilized to synthesize Self Assembled Fluorescent Organic Aggregates (SFOAs) in water with average particale size of 185 nm. Various factors affecting the self-assembly of the FOAs were optimized which include pH, concentration, temperature and chaotropic agents. The AIE properties were also utilized for the detection of changes in viscosity highlighting the utilization of the probe as a viscosity sensor (viscochromism). Furthermore, the SFOAs were used for the detection and quantification (LOD = 4.25 μ M and LOQ = 12.9 μ M) of picric acid in solution and solid state. The study presents a new Schiff base with solid-state emissive properties, displaying its photoluminescence response to various stimuli and its wide range of applications. It emphasizes the compound’s potential for use in advanced fluorescent materials designed for analytical and sensing technologies.
A naphthylimide dye-based fluorescent probe (Nap-Mem-GSH) was synthesized for the detection of Glutathione inside and outside cell membranes. This probe carried a 2-Hydroxyquinoline fragment as a recognition site on top of a naphthalimide dye, which exhibits better selective and fluorimetric response toward Glutathione in natural media. The long alkyl chain confers a cell membrane targeting role to Nap-Mem-GSH. Therefore, the detection of intra-and extracellular glutathione inside and outside the cell membrane can be realized by Nap-Mem-GSH. Meanwhile, Nap-Mem-GSH not only has a large Stokes shift (160 nm), a low detection limit and a rapid response toward GSH, but also has the advantages of low cytotoxicity and good membrane permeability to living cells, and has been successfully applied to effectively detect and image intracellular glutathione by confocal fluorescence imaging.
Titanium dioxide (TiO₂) remains one of the most investigated photocatalysts for environmental remediation; however, its practical application under visible light is still limited by its wide band gap and rapid electron–hole recombination. In this work, TiO₂ nanoparticles were synthesized by a modified polymeric precursor method using different citric acid/metal ratios, leading to materials with distinct structural and surface properties. Structural analyses confirmed the formation of anatase TiO₂ with nanometric crystallite sizes and high specific surface area. Spectroscopic and EPR analyses revealed the presence of oxygen vacancies, Ti³⁺ species, and sulfur-related surface defects, which contributed to enhanced visible-light absorption and charge separation. Among the synthesized materials, the M1C15 sample exhibited the best photocatalytic performance toward acetaminophen degradation, achieving complete removal under UV irradiation. LC–MS analyses confirmed the disappearance of acetaminophen signals after treatment and revealed the formation of intermediate compounds associated with oxidative degradation pathways and radical coupling reactions. EPR spin-trapping experiments demonstrated the generation of hydroxyl radicals (•OH), supporting the proposed photocatalytic mechanism. Under visible-light irradiation, the M1C15 sample achieved 18.2
Mercury and its compounds pose serious health and environmental risks due to their high toxicity, persistence, and bioaccumulation, particularly in the form of Hg²⁺ ions. This study reports the synthesis of a yellowish-orange emitting ionic liquid (SLIL) via a simple ion-exchange method. The SLIL shows strong photoluminescence under 365 nm UV light, which changes notably when dispersed in water as a nanosuspension (nSLIL) in the presence of Hg²⁺ ions. The probe demonstrates excellent selectivity and high sensitivity, with nanomolar detection (LOD = 5.9 nM) and quantification (LOQ = 19.9 nM) limits, making it suitable for biological applications. Additionally, a portable paper-strip sensor was developed for practical on-site mercury detection. This work highlights a promising ionic liquid-based nanomaterial for efficient environmental monitoring.
Ultraviolet (UV) radiation plays a critical role in both beneficial and harmful health outcomes, such as vitamin D synthesis or skin erythema. Accurate quantification of UV exposure relevant to health outcomes is essential in epidemiological and clinical research. We present UVdose, an R package designed to estimate biologically relevant UV doses, including vitamin D–effective UVB and erythemal UV, using the gridded UV products from the Thematic Emission Monitoring Integrated Services (TEMIS) database. The package provides user-friendly tools for integrating environmental UV exposure data, enabling reproducible and scalable analyses in population health and clinical studies.
Photocatalytically reducing CO2 is a mild and sustainable pathway for transforming greenhouse gases into value-added chemical compounds and fuels by utilizing renewable light energy. Herein, Ag-decorated NH2-MIL-125(Ti) composite compounds (denoted as Ti-MOF-xAg) with engineered metal-semiconductor interfaces were rationally fabricated via UV-assisted photodeposition. The photocatalytic performance was evaluated in a gas–solid CO2/H2O (vapor) system under UV irradiation. All Ti-MOF-xAg samples exhibit markedly better photocatalytic properties in comparison to Ag-free NH2-MIL-125(Ti). Ti-MOF-5Ag achieves the optimal performance, delivering an accumulated 218 µmol·g− 1 CO yield and 26.4 µmol·g− 1 CH4 yield within 180 min, together with apparent quantum yield and energy return on energy invested values of 7.40‰ and 2.71‰, respectively. The catalyst also maintains stable performance over consecutive cycling tests, exhibiting excellent robustness and stability. Systematic spectroscopic and electrochemical analyses reveal that the performance enhancement originates primarily via the Schottky junction at the Ag/NH2-MIL-125(Ti) interface driving directional photogenerated electron transfer from the NH2-MIL-125(Ti) LUMO to Ag and promoting electron accumulation on Ag active sites. This interfacial electron extraction effectively suppresses charge recombination and accelerates the CO2 reduction process. This work highlights noble-metal interfacial engineering as an effective strategy to boost the gas-phase CO2 photoreduction capability of Ti-based MOFs.
