Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology最新文献

{"title":"Beyond photobleaching: radical-driven photocleavage and destaining mechanisms in chromophore-biomolecule conjugates.","authors":"Victor Akpe, Ian E Cock","doi":"10.1007/s43630-026-00964-3","DOIUrl":"10.1007/s43630-026-00964-3","url":null,"abstract":"<p><p>Chromophore-biomolecule conjugates have evolved far beyond their origins as passive fluorescent labels, emerging as mechanistically rich photochemical systems capable of reporting, modulating, and disrupting biological structures with molecular precision. Although photobleaching has traditionally been regarded as an imaging artefact, growing evidence shows that high-intensity illumination can initiate radical-driven bond cleavage, structural rearrangement, and targeted molecular release. These illumination-induced transformations, manifesting as photochemical destaining are increasingly recognised as mechanistically informative rather than merely detrimental. This review integrates classical fluorescence spectroscopy with contemporary radical photochemistry to establish a unified framework describing how excited-state dynamics, microenvironmental polarity, and chromophore-protein coupling governs the transition from reversible quenching to irreversible photocleavage. By synthesising insights from spectroscopy, membrane biophysics, and photochemical reaction pathways, we delineate the mechanistic hierarchy linking singlet-state relaxation, triplet reactivity, charge-transfer processes, and radical escape. This perspective reframes photochemical destaining as a functional mechanistic probe and highlights its potential for targeted inactivation, mechanistic interrogation, and the rational design of next-generation photocleavable conjugates.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"2017-2035"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148623838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent increases in solar UV radiation across Europe: a 40-location study to identify trend boundaries.","authors":"Alois W Schmalwieser, Sebastian Lorenz, Dariia Klyshkina, Barbara Klotz, Michael Schwarzmann, Stana Simic, Alexander Mangold, Natacha Pezzetti, Kamil Láska, Marie Novotná, Martin Stráník, Brian Køster, Margit Aun, Kaisa Lakkala, Frederique Auriol, Eric Bourrianne, Romain De Filippi, Nicolas Henriot, Fanny Minvielle, Jörg Trentmann, Daniela Weiskopf, Alkiviadis Bais, Katerina Garane, Dénes Fekete, Annachiara Bellini, Alcide Giorgio di Sarra, Henri Diémoz, Luca Fibbi, Francesca Frasca, Daniele Grifoni, Daniela Meloni, Anna Maria Siani, Peter den Outer, Jos van Geffen, Edith van Putten, Bjørn Johnsen, Tove Svendby, Agnieszka Czerwińska, Janusz Krzyścin, Natalia Chubarova, Slavica Malinović-Milićević, Zoltan Nađ, Zorica Podrascanin, Anna Pribullova, Juana Arolo Pacheco, Ana Díaz Rodriguez, Carmen González, José Manuel Vilaplana, Julian Gröbner, Gregor Hülsen, Michael Higlett, Andrey Lyachev, Rebecca Rendell, Andrew R D Smedley, Ann Webb","doi":"10.1007/s43630-026-00971-4","DOIUrl":"10.1007/s43630-026-00971-4","url":null,"abstract":"<p><p>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%/yr. At 38 sites at least monthly means increases with medians between + 2%/yr and + 4%/yr. Increases were seen in satellite products of UVR, global solar radiation, and sunshine duration, too. Analysis at six stations, with data extending back to the mid-1990s, indicates that the period of statistically significant increases generally began between 2010 and 2013. Comparison of UVR data from 40 stations with a high-resolution global solar radiation trend map reveals complementary patterns, highlighting widespread but not uniform UVR changes across Europe. This combination enables figuring out the regional extent of trends. Thus, ground-based UVR measurements remain essential for quantifying changes, highlighting the need for continued monitoring with sufficiently dense measurement networks. This is also essential for understanding and mitigating the impacts of changing UVR on human health, particularly by assessing its potential for increased UVR-related skin cancer incidence and development of preventive measures. Moreover, detailed regional UVR data is essential for achieving the UN's Sustainable Development Goals, specifically in human health, sustainable cities, climate action, and environmental conservation.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"1951-1969"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148726790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of adjunct Nd-YAG laser (1064 nm) to non-surgical periodontal therapy: a systematic review and meta-analysis of randomized controlled trials.","authors":"Ahmed Atya, Ahmed Tawfik, Rim Waly, Karim Abdelazim, AlShimaa Ibrahim Abd El Aziz Elsandoby, Al-Hassan Soliman Wadan, Ahmed Elkoumi","doi":"10.1007/s43630-026-00962-5","DOIUrl":"10.1007/s43630-026-00962-5","url":null,"abstract":"<p><strong>Background: </strong>The Neodymium-doped Yttrium Aluminum Garnet (Nd: YAG) laser is proposed as an adjunct to scaling and root planing (SRP) to enhance bacterial reduction and healing in periodontitis. This study aims to evaluate the efficacy of Nd: YAG laser therapy (1064 nm) compared with SRP alone in improving clinical periodontal outcomes.</p><p><strong>Methods: </strong>This systematic review adhered to PRISMA 2020 guidelines and was prospectively registered with PROSPERO. We included only randomized controlled trials (RCTs) comparing SRP with adjunctive Nd: YAG laser therapy to SRP alone in patients with periodontitis. The primary outcomes were pocket depth (PD), plaque index (PI), bleeding on probing (BOP), and clinical attachment loss (CAL) assessments at baseline and after three months. Secondary outcomes included gingival cervical fluid (GCF) at baseline and after three months. Risk-of-bias assessment (using ROB-2) was performed independently by multiple reviewers. All statistical analyses were performed using R (version 4.4.3). The certainty of evidence for all outcomes was evaluated using the GRADE approach.</p><p><strong>Results: </strong>The systematic review and meta-analysis included 22 randomized controlled trials published between 2010 and 2025, totaling 776 patients. Meta-analysis demonstrated that adjunctive ND: YAG laser with SRP significantly improved PD reduction compared with SRP alone (MD = - 0.46 mm; 95% CI -0.82 to - 0.10; p = 0.0117), Subgroup analysis showed that split-mouth RCTs had a larger effect (MD = - 0.66 mm) than parallel-group RCTs (MD = - 0.20 mm), but the difference between subgroups was not significant. No statistically significant benefits were observed for PI (MD = - 0.03; 95% CI -0.19 to 0.13; p = 0.63), CAL (MD = - 0.04; 95% CI -0.21 to 0.13; p = 0.61), GCF volume (MD = - 0.20; 95% CI -0.45 to 0.06; p = 0.097), or BOP (MD = - 7.88; 95% CI -19.23 to 3.46; p = 0.17).</p><p><strong>Conclusion: </strong>Adjunctive Nd: YAG laser therapy provides a modest, statistically significant benefit in reducing periodontal pocket depth beyond conventional therapy alone. However, it does not demonstrate superior efficacy in improving clinical attachment levels or plaque control. Consequently, while beneficial for pocket reduction, current evidence does not support its routine universal use as a substitute for standard mechanical debridement.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"1997-2015"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148681976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UVdose: an R package for estimating ambient vitamin D-effective UVB and erythemal UV doses.","authors":"Rasha Shraim, Jos van Geffen, Lina Zgaga","doi":"10.1007/s43630-026-00959-0","DOIUrl":"10.1007/s43630-026-00959-0","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"2055-2060"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"\"Photo-physical, optical and forensic applications of Eu(III) complexes with chromone-based ligand\".","authors":"Shagun Goyat, Rajesh Kumar","doi":"10.1007/s43630-026-00965-2","DOIUrl":"10.1007/s43630-026-00965-2","url":null,"abstract":"<p><p>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% to 88.61%, while in solid phase range from 85.34% to 98.41%. The CCT values of complexes in solution range from 1715.12 to 1985.53 K and in solid phase ranges from 1795.20 to 3344.06 K, confirming their use in warm light-emitting material. These complexes were also utilized for developing latent fingerprints for various forensic applications. The E5 complex demonstrated excellent performance in latent fingerprint visualization under 365 nm UV illumination, revealing clear ridge patterns and minutiae including bifurcations, ridge endings, bridges, islands, and crossovers. These findings highlight the potential of the synthesized Eu(III) complexes as dual-functional materials for both photonic devices and forensic detection applications.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"2071-2090"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148805267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of ultraviolet light exposure on blood pressure: a systematic review.","authors":"Pirus Ghadjar, Natalia Syzonenko, Anastasia Lucia Strzebinczyk, Siddharth Arora, Benjamin Michel, Moritz V Scharr, Helmut Piazena, Daniel Zips, Georg Seifert","doi":"10.1007/s43630-026-00970-5","DOIUrl":"10.1007/s43630-026-00970-5","url":null,"abstract":"<p><strong>Background: </strong>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.</p><p><strong>Objective: </strong>To systematically review the available evidence on effects of UV exposure on blood pressure, with a focus on hypertension in human populations.</p><p><strong>Methods: </strong>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.</p><p><strong>Results: </strong>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.</p><p><strong>Conclusions: </strong>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.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"2037-2046"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148805232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observation of glutathione intra- and extracellular membrane with large Stokes shift probe modified by long alkyl chains.","authors":"Lin Li, Shao-Bin Sun, Dan Qiao, Jing Zhou, Lin-Qing Wang, Jian-Yong Wang","doi":"10.1007/s43630-026-00961-6","DOIUrl":"10.1007/s43630-026-00961-6","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"1903-1912"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148709152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aggregation-controlled photophysics of m-THPP: restoring singlet oxygen generation via albumin and pluronic carriers.","authors":"Aleksander Kolman, Anna Lewandowska-Andralojc","doi":"10.1007/s43630-026-00960-7","DOIUrl":"10.1007/s43630-026-00960-7","url":null,"abstract":"<p><p>The photophysical properties of meso-tetra(hydroxyphenyl)porphyrin (m-THPP) were investigated to elucidate how aggregation in aqueous media affects its ground- and excited-state behavior and to identify carrier systems capable of preserving its photodynamic activity under near-physiological conditions. Spectroscopic studies in methanol-phosphate-buffered saline mixtures showed that m-THPP undergoes pronounced aggregation at high water content, leading to strong broadening and red shifting of the absorption bands, quenching of singlet and triplet excited states, and complete suppression of singlet oxygen generation in aqueous buffer. To prevent aggregation, m-THPP was formulated using polymeric micelles based on Pluronic P123 and Pluronic F127, as well as by complexation with bovine serum albumin. All carrier systems stabilized predominantly monomeric m-THPP in buffer, but with markedly different efficiencies. The albumin complex and P123 micelles provided superior stabilization, yielding higher fluorescence efficiencies, longer triplet lifetimes, and enhanced singlet oxygen generation in contrast, incorporation into the more hydrophilic F127 micelles promoted partial aggregation of m-THPP, leading to reduced photodynamic performance. These results demonstrate that aggregation is the key factor limiting the activity of m-THPP in aqueous media and that rational selection of carrier systems enables effective control of its photophysical properties and photodynamic efficiency.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"1891-1902"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148623818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond total irradiance: a PCA-based filtering framework identifies wavelength-dependent biological signatures of sunlight exposure.","authors":"Jiayue Gu, Andrew C Stevenson, Chris Dibben, Richard B Weller","doi":"10.1007/s43630-026-00966-1","DOIUrl":"10.1007/s43630-026-00966-1","url":null,"abstract":"<p><p>Natural sunlight contains ultraviolet, visible and near-infrared radiation, but these bands are highly correlated under everyday environmental conditions. This collinearity limits the extent to which population studies can distinguish overall ambient sunlight availability from wavelength-dependent biological associations. Using UK Biobank data, we linked satellite-derived ambient spectral irradiance estimates to baseline blood biochemistry measurements. We examined unweighted UVB (280-315 nm), UVA (315-400 nm), blue (450-495 nm), red (620-750 nm) and near-infrared (700-1100 nm) irradiance averaged over the 14 days preceding blood sampling. Principal component analysis (PCA) was used to characterise the dominant common variation across spectral bands. We then filtered out the reconstructed PC1 contribution from each band to derive spectral residuals, which were evaluated in multivariable regression models. Inter-band correlations were extremely strong (r = 0.94-1.00), and PC1 explained 98.3% of total variance. Models using the original band-specific irradiance estimates produced highly concordant biomarker association patterns across wavelengths, consistent with dominance of common ambient irradiance variation. In contrast, PC1-filtered spectral residuals revealed wavelength-dependent contrasts. Vitamin D showed preferential positive association with ultraviolet residuals, consistent with its established UVB-dependent biology and providing a positive validation example. Several metabolic, hormonal and inflammatory biomarkers also showed contrasting residual associations across ultraviolet and longer-wavelength bands. These findings confirm that known wavelength-dependent biological responses can be recovered from highly collinear environmental sunlight data using a PCA-based filtering framework. They also suggest that additional blood biomarkers may show wavelength-dependent associations with everyday ambient sunlight exposure. The spectral residuals should be interpreted as statistical constructs that highlight small deviations from the dominant common variation, rather than as physically independent wavelength exposures or measurements of personal skin dose.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"1927-1937"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148805278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photodynamic anti-biofilm PHEMA/Rose Bengal hydrogels enhanced by iodide: evidence for hydrogen peroxide and triiodide formation.","authors":"Ana M López-Fernández, Valentina Quintero, Sofía Ballesta, Isabel García-Luque, Francisco Galindo","doi":"10.1007/s43630-026-00968-z","DOIUrl":"10.1007/s43630-026-00968-z","url":null,"abstract":"<p><p>Biofilm-associated infections remain a major challenge for biomedical devices, motivating the development of light-activated antimicrobial materials. Here we report the antibiofilm activity (against Staphylococcus aureus and Pseudomonas aeruginosa) of a photodynamic hydrogel consisting of Rose Bengal (RB) physically entrapped within a crosslinked poly(2-hydroxyethyl methacrylate) (PHEMA) matrix. Under visible-light irradiation, RB-PHEMA alone produced only modest reductions (ca. 1 log), whereas addition of iodide markedly enhanced antibiofilm performance, yielding a 4.2-log reduction for S. aureus and a 1.7-log reduction for P. aeruginosa. To elucidate the basis of iodide potentiation, we conducted a systematic spectroscopic study under irradiation with varying concentrations of KI and NaI. Long-lived products consistent with iodide oxidation by singlet oxygen were detected, including triiodide (I₃^-) and hydrogen peroxide (H₂O₂). I₃^- was observed within the PHEMA hydrogel but not in the supernatant, consistent with electrostatic retention in the polymer network, while H₂O₂ was detected both at the hydrogel surface and in the surrounding solution, indicating diffusion away from the material. These findings support a mechanism in which diffusible H₂O₂, together with polymer-retained iodine species, contributes to biofilm inactivation beyond short-lived reactive intermediates. Practically, 10 mM iodide was sufficient to reach the maximum I₃^- signal, and NaI performed comparably to KI. The transparency and flexibility of the hydrogel support applications requiring conformal contact and back-illumination. Finally, photobleaching of RB within the hydrogel is effectively eliminated in the presence of iodide, providing an additional practical advantage of iodide as a potentiating additive.</p>","PeriodicalId":520750,"journal":{"name":"Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology","volume":" ","pages":"1939-1949"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148815470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}