"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.
Photoproducts of the photosensitizer protoporphyrin IX (PpIX) may have diagnostic and therapeutic relevance in photodynamic diagnosis (PDD) and photodynamic therapy (PDT), as they possess fluorescence and photosensitizing properties and could serve as a complementary dosimetry index alongside photosensitizer photobleaching. Consequently, a detailed characterization of these photoproducts is necessary for exploring their potential application in PDD and PDT. Further, understanding the processes of photobleaching and photoproduct formation will be useful for diagnosis and treatment planning in PDD and PDT. In this study, the formation of four photoproducts previously observed from the irradiation of PpIX-dimethyl ester was extended to investigate their formation from PpIX. PpIX in solution was irradiated at 405 and 635 nm, wavelengths relevant to PDD and PDT, and the formation of the photoproducts was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Hydroxyaldehyde and formyl photoproducts, and their isomeric forms, were identified, and their fold increases were evaluated under different irradiation conditions. Although the physicochemical properties of photoproducts depend on the environment, this solution-based study provides fundamental understanding of the photochemical reaction of PpIX and its photoproducts under clinically relevant irradiation conditions and may aid studies aimed at exploiting photoproducts for improved dosimetry and therapeutic outcomes in PDD and PDT.
New entrants in scientific research often presume that quality and impactful research requires access to sophisticated and expensive instrumentation, resulting in discouragement for laboratories with limited in-house facilities. The present review, principally based on our laboratory work, challenges this concept by demonstrating that the foundation of meaningful research lies, to a good extent, in keen societal observation, inquisitiveness, logical analysis, and rationalization, rather than mere instrumentation; although none can ignore the complementary role and impact of tailor-made and other contemporary instrumentation when accessible. Through a series of conceptually driven strategies, largely developed in our laboratory, this review demonstrates how judiciously designed simple, strategic experimental techniques can yield productive, innovative, and socially relevant outcomes across photochemistry, biophysical chemistry, and general chemistry. The present review reports a breakthrough in using micelles as "broker" to improve the sensing ability of a fluorosensor toward biologically and environmentally relevant analytes such as Cu2+ by orders of magnitude, achieved simply by exploiting absorption and fluorescence spectroscopy; the first-ever demonstration of a cationic sensor detecting a cationic analyte in aqueous medium; selective detection of the highly toxic cyanide ion in water employing merely an absorption spectrophotometer; a low-cost strategy for the synthesis of gold nanoparticles of desired dimensions, where particle size can be measured using routine UV-vis spectrophotometry, rather than advanced and costly instruments such as TEM and SEM. This review further presents concept-based fundamental advances in molecular photophysics, including discovery and mechanistic understanding of S2 emission in some 1,2-dicarbonyl compounds, elucidation of asymmetric solvation of ESIPT-prone probes in protic solvents, and innovative strategies to overcome the spectral overlap constraint in Förster resonance energy transfer (FRET) by coupling it with other photoprocesses such as excited-state proton transfer (ESPT) or intramolecular charge transfer (ICT). Further, development of multifunctional composite hydrogels exhibiting exceptionally high proton conductivities is discussed, alongside novel mechanistically guided strategies like electrostatic pushing, micelle-mediated switchability of endogenous/exogenous modes for targeted drug delivery and cyclodextrin-assisted excretion of accumulated drugs from the cell membranes are presented. Collectively, these studies demonstrate how rational translation of societal observations into fundamental chemical principles can provide a balanced and realistic framework for conducting quality research by integrating conceptual innovation, accessible methodologies, and collaborative use of advanced infrastructure. The central objective of this review was to motivate early-career researchers, particularly working in laboratories with limited in-house resources, to pursue quality research through critical observation, creative thinking, and strong analytical insight with strategic and judicious use of accessible techniques, complemented by shared high-end resources.
Head and neck cancer (HNC) affects thousands globally, with high morbidity rates due to standard treatments like surgery and radiation. Photodynamic therapy (PDT) has shown great promise as a less destructive alternative, selectively targeting tumors while preserving healthy tissue. However, assessing treatment response in the days after PDT is challenging due to significant inflammation and the subsequent vascular shutdown of the tumor. We hypothesize that fluorescence paired-agent imaging (PAI) can provide early molecular insights within 24 h of PDT to evaluate treatment efficacy. PAI utilizes two fluorescent agents to correct for perfusion-related changes, allowing for accurate quantification of key signaling proteins. Specifically, we tracked epidermal growth factor receptor (EGFR) response to benzoporphyrin derivative monoacid (BPD)-PDT at 690 nm, with light fluences ranging from 0 to 100 J/cm2. Twenty-four hours post-PDT, EGFR concentrations were measured using PAI with ABY-029 and IRDye 680LT as targeted and untargeted agents, respectively. These findings were compared to histopathology (H&E and EGFR IHC). Our histological results demonstrated that EGFR expression increased with low PDT doses (10 and 25 J/cm2) and decreased below baseline expression with higher doses (50 and 100 J/cm2). Fluorescence intensity of both ABY-029 and IRDye 680LT was highly variable with treatment dose and was not correlative to tumor response. In contrast, the PAI-binding potential (BP) corresponded to the varying EGFR expression measured by pathology. In vivo and ex vivo PAI BP was moderately to highly correlative to percent area IHC EGFR expression (r = 0.65 and 0.54, p < 0.05, respectively) and the in vivo 100 J/cm2 treatment group demonstrated significantly lower BP than the controls. PAI emerges as a promising tool for tracking early molecular changes in HNC, with potential clinical applications.
Far-UVC (200-235 nm) has emerged as a safe and effective modality to inactivate pathogens in an indoor setting. trans-urocanic acid (UCA) is a chromophore that resides in the stratum corneum of the skin and is converted into the more biologically active cis isomer upon ultraviolet radiation (UVR) exposure where it initiates immunosuppression. The immunomodulatory potential of far-UVC exposure within the skin is currently unknown, particularly the conversion of trans- to cis-UCA and the resulting downstream signaling. Here, we confirm that far-UVC at 222 nm photoisomerizes trans-UCA into its cis isomer with levels comparable with solar simulated radiation (SSR). Further, we examined changes in cytokine secretion released from the supernatant and mRNA expression of IL-6 and IL-8 as well as key signaling mediators following far-UVC and SSR irradiation in primary human keratinocytes with or without irradiated UCA. Far-UVC alone induced modest non-significant trends in IL-6 and IL-8 secretion, ROS, and C-Jun phosphorylation. In the presence of irradiated UCA, higher mean levels of these mediators and increased STAT3 phosphorylation were observed 24 h post-exposure alongside elevated IL-6 and IL-8 expression. SSR-exposed keratinocytes also increased cytokine secretion; however, responses in the presence of irradiated UCA were associated with lower mean inflammatory signaling and increased p53 phosphorylation, accompanied by non-significant changes in NF-κB activity. Our findings demonstrate that far-UVC can induce trans-cis-UCA photoisomerization and highlight potential interactions between UCA and UVR-induced signaling pathways in keratinocytes. While biological variation in samples perhaps masks significant differences, these observations and trends can inform future work and contribute to a better understanding of chromophore-mediated photochemical processes that may influence cellular responses to far-UVC exposure.
This study assessed the effects of photobiomodulation with 450 and 635 nm laser wavelengths on the release of transforming growth factor-beta (TGF-β), bone morphogenetic protein (BMP)-2, fibroblast growth factor (FGF)-2, and vascular endothelial growth factor (VEGF) from human dental pulp stem cells (DPSCs). In this in vitro study, human DPSCs were cultured and randomly assigned to two experimental groups to undergo 450 and 635 nm laser irradiation with 2, 4, and 6 J/cm2 energy densities, and one control group (n = 5). After laser irradiation, total RNA was then extracted, cDNA was synthesized, and expression of TGF-β, FGF-2, BMP-2, and VEGF was assessed by real-time polymerase chain reaction (PCR). Data were analyzed by one-way and two-way ANOVA and Tukey's test (alpha = 0.05). The effects of laser wavelength, energy density, and their interaction were significant on the release of all growth factors (p < 0.0001). Laser irradiation in almost all subgroups increased the release of growth factors. By an increase in energy density, the release of BMP-2 and FGF-2 in both wavelengths, VEGF in the 635 nm group, and TGF-β in the 635 nm group increased while the release of VEGF in the 450 nm group decreased (p < 0.05). The amount of released growth factors in the 635 nm group was higher than in the 450 nm group (p < 0.05). PBMT with 450 and 635 nm lasers increased the release of TGF-β, BMP-2, FGF-2, and VEGF from human DPSCs in most energy densities, which may be of use in regenerative endodontics.
Chalcones are α,β-unsaturated ketones with extended π-conjugation, making them promising scaffolds for the development of organic UV filters. In this study, a series of substituted chalcones inspired by the chemical structure of avobenzone (AVO) was synthesized and systematically evaluated for UV absorption profiles, photostability, antioxidant potential, photoprotection, and safety-related properties. Among the compounds, the 2-hydroxychalcones 3ca and 3cb showed the most promising profiles. Chalcone 3ca exhibited λmax at 365 nm, critical wavelength of 386 nm, UVA/UVB ratio of 6.3, and molar absorptivity of 58,880 M-1 cm-1, whereas 3cb showed λmax at 353 nm, critical wavelength of 376 nm, UVA/UVB ratio of 3.2, and molar absorptivity of 28,900 M-1 cm-1. Both compounds fulfilled broad-spectrum protection criteria and showed <5% degradation after UVA and UVB irradiation, with photostability comparable to benzophenone-3 and superior to AVO. Formulations containing 3ca and 3cb reduced UVA-induced DNA damage by 90.4% and 95.1%, respectively. Skin permeation studies demonstrated predominant retention in the stratum corneum (94.1% for 3ca and 97.4% for 3cb), minimal penetration into viable epidermis and dermis, and no detectable compound in receptor fluid. Both chalcones showed no relevant irritation in the HET-CAM assay and no significant alterations in skin biometric parameters after topical application. Collectively, these findings support the potential of hydroxy-substituted chalcones as photostable broad-spectrum UV filters for topical application.
Shade stress is a critical environmental constraint that significantly affects plant growth, development, and productivity. Phytochromes, as red and far-red light photoreceptors, play a central role in perceiving shading signals and orchestrating complex physiological and molecular responses in crops. This review provides an analysis of phytochrome-mediated shade stress, highlighting its impacts on key plant processes such as photosynthesis, hormonal regulation, gene expression, and biomass accumulation. We discuss the roles of red and far-red light in modulating phytochrome activity and downstream signaling pathways, emphasizing how these photoreceptors interact with hormonal networks to influence plant morphology, flowering, and stress adaptation. The phytochrome signaling cascade involves intricate light perception and gene regulatory mechanisms that enable plants to adjust their growth under low-light conditions. Differential responses of C3 and C4 plants to shade stress are also examined, revealing species-specific strategies for coping with reduced light intensity. Moreover, the review outlines current approaches for managing shading stress, including agronomic practices, genetic interventions, and molecular breeding strategies aimed at enhancing light-use efficiency. By synthesizing recent findings, this article provides insights into the functional roles of phytochromes in mediating shade avoidance and tolerance, offering a framework for future research on crop adaptation to heterogeneous light environments. Understanding phytochrome-mediated mechanisms is crucial for developing resilient cropping systems that maintain productivity under suboptimal light conditions.
Light-emitting diodes (LEDs) are light sources that can be used for photobiomodulation to treat various diseases and clinical conditions. Growing evidence suggests that photobiomodulation is a promising treatment for rheumatoid arthritis (RA) and osteoarthritis (OA) because of its analgesic and anti-inflammatory effects. However, such evidence is primarily based on studies evaluating low-power laser-based photobiomodulation, and few studies have assessed the efficacy of LED photobiomodulation in the treatment of RA and OA. Thus, this study aimed to review studies on LED photobiomodulation for the treatment of RA and OA, summarizing the irradiation parameters and conditions, and reporting the study types and main results. Studies on the effects of LED photobiomodulation on RA and OA were accessed via PubMed. Data from accessed studies show that LED photobiomodulation has been carried out with red and infrared LEDs based on in vitro and in vivo experimental models. This therapy may decrease arthritic markers, including edema, hyperalgesia, inflammation, cartilage degradation, extracellular matrix alterations, and proinflammatory cytokine levels. LED photobiomodulation could be as effective a therapy as laser photobiomodulation, but further clinical studies are necessary to verify its therapeutic benefits in both RA and OA.
Germicidal ultraviolet (GUV) air treatment technologies can be effective and safe for reducing airborne disease transmission. Today, GUV systems are designed and evaluated using simulation and measurement tools that require further assessment of their accuracy in estimating fluence rate and irradiance. This article reports results from two experiments where two simulation software (Visual Lighting and Photopia) and two measurement techniques (tetrahedron and cubic approximations) were evaluated against chemical actinometry for quantification of GUV fluence rate in a chamber. Additionally, Visual and Photopia were compared to measurements of planar UV-C irradiance for eye and skin exposure. Results showed that overall mean fluence rates were similar between actinometry and both simulation software for WR GUV systems as well as between actinometry and Photopia for UR GUV systems. The tetrahedron approximation better predicted overall mean fluence rate for WR and UR GUV systems, compared to a cubic approximation which tended to overestimate it. Compared to measurements, simulated eye and skin irradiance varied, with higher variability in simulated eye irradiance. The evaluated simulation software can be used to guide the design of GUV systems but must be supplemented with in situ measurements.
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.
Epithelial ovarian cancer (EOC) is a lethal disease typically diagnosed at a late stage. There is an urgent need for treatment modalities that eliminate microscopic metastatic deposits missed by standard therapies while simultaneously engaging antitumor immunity. Photodynamic therapy (PDT) has demonstrated immune-enhancing effects, including photodynamic priming (PDP), wherein sublethal photodynamic stress remodels the tumor microenvironment to facilitate immune activation and infiltration. Here, we investigate cancer-targeted photoimmunotherapy (PIT), a molecularly targeted form of PDT, as a strategy to build upon and potentially enhance PDP by selectively depleting cancer cells while preserving immune effectors critical to antitumor responses. Using a 3D Matrigel dome model incorporating human ovarian cancer spheroids and allogeneic immune cells, we establish a broadly accessible imaging and analysis pipeline based on fluorescent labeling and 3D confocal microscopy to quantify cancer and immune cell viability. In this system, the presence of T cells or peripheral blood mononuclear cells enhances cancer depletion following PIT, consistent with stimulation of an antitumor immune response. Importantly, PIT spares significantly more T cells and NK cells compared to untargeted PDT and cetuximab at equivalent concentrations. PIT reduces spheroid size while preserving effector immune populations within the tumor microenvironment. Together, these findings suggest that targeted PIT may extend the immune-modulatory foundations established for PDT and PDP, offering a strategy to simultaneously eradicate residual tumor deposits and promote antitumor immune priming in EOC.
The use of insect repellents in areas with high solar radiation exposure has increased significantly due to dengue and chikungunya epidemics in Brazil. However, limited research exists on the photostability of these substances under ultraviolet (UV) radiation. This study aimed to evaluate the photolability of two common insect repellents, N,N-diethyl-3-methylbenzamide (DEET) and ethyl 3-[acetyl(butyl)amino]propanoate (IR-3535), and commercial products containing these active ingredients, including combinations with selected chemical UV filters, under simulated UV radiation using Raman spectroscopy. Samples were exposed to a UV-A + UV-B light source (7.0 mW/cm2) for 8 h, and Raman spectra were collected before and after irradiation. Pure DEET, IR-3535, ethanol, isopropyl myristate, and the commercial product containing IR-3535 exhibited no significant spectral changes following UV exposure. In contrast, DEET diluted in ethanol and the commercial product containing DEET exhibited significant changes, including a decrease in DEET peaks at 524, 690, 1003, and 1606 cm-1 and an increase in the ethanol peak at 884 cm-1. When UV filters were added to the commercial products containing DEET and IR-3535, no significant changes were observed in the peaks associated with DEET, IR-3535, or ethanol. However, alterations were observed in the spectra of the UV filters, suggesting that the filters conferred photoprotection to the repellent molecules via a competitive photon absorption mechanism, but also exhibited photodegradation of their own molecules. These findings suggest that the commercial product containing DEET is photolabile under UV exposure and that the inclusion of chemical UV filters can restore photostability.
Thanks to incalculable efforts by teams of scientists and physicians over the past half-century, many cancer diagnoses that would have previously seemed terminal are now considered treatable or even curable with optimization of existing treatment strategies and the introduction of novel treatment methodologies. One rising treatment paradigm with the potential to improve patient outcomes and experiences is photomedicine, a group of light-activated treatments that can be applied systemically and activated locally. As the work of developing new phototherapeutic treatments and agents for use in cancer patients progresses, in vivo experimentation is a necessary hurdle, costing both time and resources. The use of zebrafish as a vertebrate tumor model for early-stage animal testing has the potential to increase the overall efficiency of the research process. Zebrafish are a model organism that allow for numerous tumor presentations and drug-delivery options to be tested at scale with a low turnaround time relative to other in vivo vertebrate models. The transparency of an embryonic or larval zebrafish's body allows for real-time observation of drug dispersal and effects of treatment. These qualities allow zebrafish to serve as a useful screening tool for identifying promising candidate photosensitizers before embarking on mammalian studies.
Healthcare-associated infections (HAIs) are a known and growing problem worldwide, including those caused by ESKAPEE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli. Far-UVC is a novel disinfection method that inactivates pathogenic microbes in air and on surfaces, but is safe for use in occupied spaces. We will implement a multi-site, double-blinded, clustered randomized controlled trial (cRCT) in two hospitals with a high burden of ESKAPEE pathogens. Intervention spaces will receive functioning far-UVC lamps and control arm spaces will receive visually identical lamps that do not emit UV light (shams), randomly allocated to 10 sites per arm per hospital. We will collect environmental samples (air and surface swabs) and measure ESKAPEE pathogens via culture and sequencing in longitudinal monitoring. We hypothesize that the prevalence of ESKAPEE pathogens on intervention site surfaces will be reduced, compared with control arm surfaces.
Healthcare-associated infections (HAIs) remain a significant concern in dental settings, especially in light of increasing antimicrobial resistance. This study aimed to characterize and evaluate the efficacy of an ultraviolet C (UV-C) disinfection device specifically developed as an additional resource for dental clinics and healthcare settings. Colorimetric dosimeters were strategically distributed at different points and vertical levels to monitor UV-C radiation distribution in the environment. The emission spectrum and radiation intensity were measured using spectral measurement techniques, while microbiological analyses were conducted on seven commonly encountered surfaces in dental offices using mannitol salt agar selective for Staphylococcus aureus and Staphylococcus epidermidis. The results revealed a significant reduction in colony-forming units (CFUs), exceeding 90% at most sampling points (p < 0.05). An exponential falloff of irradiance with distance from the UV-C source was observed, highlighting the importance of proper positioning of the equipment. Notably, the UV-C device proved effective even on surfaces with higher microbial loads, such as the armrest of the dental chair. The findings demonstrate that both time and distance significantly affect disinfection efficacy, and that purpose-built UV-C devices are viable as complementary tools to conventional chemical cleaning and disinfection protocols.