Metal oxide nanomaterials (MO NMs) have recently emerged as innovative materials for environmental and health remediation. The phyto-synthesis of MO NMs is particularly fascinating because of its eco-benign approach and distinctive physicochemical modifications. Therefore, this study aimed to synthesize Echinops kebericho Mesfin tuber extract mediated ZnO and ZnO-MgO NMs and to evaluate their photocatalytic, antibacterial, and anti-inflammatory efficacies. The structural and morphological characterizations of synthesized materials were performed through spectroscopic and microscopic approaches. XRD analysis has shown the formation of pristine ZnO NPs and ZnO-MgO nanocomposites (ZM NCs) with wurtzite ZnO and periclase MgO phases. The corresponding crystallinity indices were 91.4% and 94.6%, while crystallite sizes were 10.17 nm and 14.87 nm, respectively. UV-Vis-DRS demonstrated the optical band gaps of 3.14 eV for ZnO and 3.85 eV for ZM. SEM and TEM/HRTEM analyses demonstrated the formations of predominantly spherical aggregates of ZnO NPs and ZM NCs with respective average particle sizes of 10.03 nm and 12.23 nm. The biofabricated MO NMs exhibited the photocatalytic degradation efficiencies of 81.19-98.12% under UV and 71.38-95.80% under visible irradiation. The MO NMs were demonstrated the in vitro antibacterial activities with inhibition zones of 25 ± 0.52 to 33.5 ± 0.48 mm against selected bacterial strains. The anti-inflammatory efficacies of biosynthesized ZnO and ZM were 91.64% and 96.9%, respectively. Overall, the biosynthesized MO NMs have exhibited promising multifunctional activities, with ZM consistently demonstrating enhanced photocatalytic, antibacterial, and anti-inflammatory activities.
Purpose This study evaluated the influence of photodynamic therapy (PDT) performed with different photosensitizers (PSs), indocyanine green (ICG), curcumin (CUR), and methylene blue (MB), associated or not with calcium hydroxide as intracanal medication (ICM), on the mechanical properties of intraradicular dentin, degree of conversion (DC), and the integrity (voids and bubbles) of the adhesive interface of glass-fiber posts (GFPs). Materials and methods 112 bovine incisors were allocated into eight groups (n = 14) according to the use of PDT, ICM and PSs, including a negative (no PDT/no ICM) and positive (no PDT/with ICM) control groups. After 14 days, ICM was removed, root canals were obturated, and GFPs were cemented. Hardness, elastic modulus, adhesive integrity, and resin cement DC were evaluated in three root thirds (cervical, middle, and apical). Results Adhesive integrity analysis revealed a higher incidence of voids in PDT-only groups, whereas the association with ICM reduced void formation in the ICG and MB groups. DC was consistently higher in the cervical third, unrelatedly of the protocol adopted. PDT with CUR without ICM resulted in the highest dentin hardness in the apical third. ICM increased elastic modulus in the middle third of the CUR group but reduced it in the positive control group. Hardness was generally higher in the cervical and apical thirds and became more homogeneous following ICM application. Conclusions MB-mediated PDT associated with ICM proved to be a suitable protocol yielding favorable mechanical behavior of intraradicular dentin and satisfactory adhesive interface integrity of GFPs across all root thirds.
Rhodopsin (Rho), a prototypical G protein–coupled receptor (GPCR) is the sensory receptor essential for dim-light vision. Its misfolding is a major cause of retinitis pigmentosa (RP), a group of inherited retinal degenerative diseases. Pharmacological chaperones that stabilize misfolded Rho represent a promising therapeutic strategy, yet systematic approaches to identify such modulators remain limited. In this study, we present the results of a computational study aimed to identify and characterize potential allosteric binding sites in Rho. For this purpose, extensive molecular dynamics (MD) simulations were performed to capture the conformational plasticity of Rho, followed by clustering analysis to obtain representative receptor conformations. Fragment-based mapping (FTMap) of these structures revealed nine transient pockets (P1–P9) across the receptor surface.The characterized sites were used to elucidate the binding mode of the small-molecule modulator retigabine. Ensemble docking and MD simulations permitted to identify a combined P1+P2 site as a prospective binding location. To validate the prediction, experimental studies were conducted using recombinant wild-type (WT) Rho and the Q361.31A Rho mutant. Spectroscopic analyses showed that retigabine does not significantly alter the photobleaching and acidification behaviour of either protein. However, fluorescence-based assays revealed that retigabine accelerates Meta II decay and retinal release in WT Rho but not in the Q361.31A Rho mutant, supporting the involvement of Gln36 in ligand binding. Moreover, retigabine treatment attenuated the increase of intrinsic fluorescence observed in illuminated WT Rho, whereas no significant effect was detected in the Q361.31A mutant, consistent with the proposed role of Gln36 as a key residue within the prospective P1+P2 retigabine-binding site.The results of the present work establish a framework for the rational discovery of novel allosteric modulators targeting rhodopsin, with potential therapeutic implications for retinitis pigmentosa.
CuO/Cu2O/ZnO ternary photocatalysts with different CuO:Cu2O:ZnO ratios were synthesized via a facile wet-chemical precipitation method and investigated for the degradation of organic pollutants under xenon-lamp irradiation. The effects of phase composition on structural, morphological, optical, and photocatalytic properties were systematically evaluated by XRD, Williamsons - Hall analysis, FESEM, EDS, Raman, FTIR, and UV-Vis spectroscopy. XRD and Raman results confirmed the coexistence and successful strructural integration of ZnO, Cu2O, and CuO phases, while UV-Vis analysis revealed the combined optical contribution of wide-band-gap ZnO and visible-light-responsive copper oxide phases. Control experiments verified that the self-photolysis of the target pollutants was negligible. Among the investigated compositions, the 1:1:2 (CuO/Cu2O/ZnO) photocatalyst exhibited the highest activity, achieving nearly complete Rhodamine B degradation within 60 min with an apparent rate constant of 0.0822 min-1. The optimized sample also showed high ciprofloxacin removal efficiency of approximately 90-95% after 60 min, demonstrating its applicability toward both dye and antibiotic pollutants. In addition, the photocatalyst retained high activity after five consecutive cycles, with degradation efficiencies of 99.2%, 97.8%, 96.2%, 95.8% and 93.2%, and maintained its crystalline structure after reuse. The enhanced photocatalytic performance is attributed to the synergistic effect of composition-engineered CuO/Cu2O/ZnO heterojunctions, improved light absorption, and efficient interfacial charge separation, which was further supported by radical scavenging experiments identifying superoxide and hydroxyl radicals as the predominant active species. These results indicate that Zn-rich CuO/Cu2O/ZnO ternary heterostructures are promising photocatalysts for aqueous pollutant degradation.
Light-mediated processes, prevalent in fields like catalysis and medicine, utilize photons to induce changes in matter. To comprehend these processes, one must have knowledge of light sources, light-absorbing molecules, environmental conditions, and reaction kinetics. Mathematical approximations, such as the quasi-steady-state approximation (QSSA), play a crucial role in unraveling the mechanisms of these intricate reactions. QSSA simplifies complex photochemical reactions by assuming short-lived intermediates and constant reactant concentrations. However, this reductionist approach can be inaccurate for complex reactions, particularly when dealing with long-lived species, photobleaching, or large-scale processes. While QSSA is valuable, its limitations necessitate a profound understanding of its mathematical and chemical foundations. In this tutorial review, we present the reader with foundational, historical, and practical examples on the use of QSSA that can be used in undergraduate and graduate training.
Introduction Cardiovascular diseases (CVDs) remain a leading cause of mortality, fundamentally associated with endothelial dysfunction. Photobiomodulation (PBM) has been shown to modulate endothelial functions, but a lack of precise mechanisms has prevented robust clinical protocols that motivated the current study. Methods Endothelial progenitor cells were grown and subjected to a dose-dependent Angiotensin II and centrifugation-induced shear-related mechanical stress. PBM treatments were carried out using five wavelengths: 449 (blue), 532 (green), 588 (yellow), 660 (red), and 802 (infrared) nm at low, moderate and high doses. Harmonized PBM using wavelength specific photon energy (photonic fluence) and Einstein dosing were employed at constant target surface irradiance of 10 mW/cm2 and varying treatment times. Cell metabolic viability with AlamarBlue assay, reactive oxygen species (ROS – H2O2) generation with Amplex Red assay, and Nitric Oxide (NO) production with Griess assay were assessed. Data was analyzed using one-way or two-way ANOVA according to the experimental designs (p < 0.05). Results Endothelial dysfunction induced by a combination of 10 µM Ang-II and centrifugation significantly reduced cell metabolic viability (n = 4, p = 0.0018, 95% CI = 8359,451 – 41,778,754), decreased ROS (H2O2) levels (n = 4, p = 0.0178, 95% CI = 30,462 – 286,175) and reduced NO (n = 4, p = 0.0123, 95% CI = 0.0530 – 0.2636) compared to controls. PBM treatments (green, 532 nm, 10 mW/cm2, 225 s, 1.10 ɇ) most prominently (n = 4, p = 0.0012) improved endothelial metabolic viability. PBM treatment also significantly (n = 4, p = 0.0119, 95% CI = -406,297 – -57,963) elevated ROS (H2O2) levels within 15 min and recovered NO expression significantly (n = 4, p = 0.0446, 95% CI = -0.2144 – 0.0038) compared to controls. Conclusion PBM treatments successfully improved acute endothelial dysfunction markers, suggesting a mechanistically rationalized clinical protocol is feasible. Further mechanistic, in vivo and clinical studies could establish PBM as a non-pharmacological adjunctive therapeutic approach in safe and effective CVD management.
The rise of drug-resistant and emerging pathogens demands innovative approaches that integrate rapid diagnosis with precise therapy. This review provides a comprehensive and critical analysis of recent progress in biophotonics for managing infectious diseases, with a particular focus on integrated theranostic strategies and their pathways to clinical translation. We systematically evaluate state-of-the-art optical biosensors, including fluorescence, surface-enhanced Raman scattering, CRISPR-based systems, and microfluidic chips positioning them not as broad replacements for centralized molecular testing, but as rapid, phenotype revealing tools for frontline triage and point-of-care decision making. We emphasize synergistic designs, such as combined photothermal-chemodynamic therapy and phage-targeted platforms that bridge detection with targeted killing. Crucially, the review highlights the pragmatic challenges of clinical translation, including standardization, light penetration, and device integration. We conclude that the future of infectious disease management will be advanced by practical biophotonic systems that deliver precise, light-based interventions guided by timely diagnostics, offering a powerful complement to antimicrobial stewardship.
This study focuses on the synthesis of tri-bromine containing asymmetric porphyrins for their use as photosensitizers in photodynamic therapy and photodynamic antimicrobial chemotherapy. The porphyrins were modified in various ways including quaternization which introduced a positive charge. The photophysical and photochemical properties were investigated and the porphyrins have good singlet oxygen quantum yields. The photodynamic therapeutic activities of the complexes were tested against MDA-MB-231 breast cancer cell lines and E. coli. Some of the complexes showed some good activity against the considered targets.
Influenza represents a persistent and dynamic global health challenge, characterized by annual epidemics and the ever-present specter of a high-mortality pandemic, particularly from avian-origin strains like H5N1. Current therapeutic arsenals, predominantly reliant on viral neuraminidase inhibitors and RNA polymerase inhibitors, face significant limitations including narrow windows of efficacy, the rising prevalence of antiviral resistance, and an inability to modulate the deleterious host immune responses that often dictate clinical severity. Ultraviolet Blood Irradiation (UBI) emerges as a compelling, mechanistically distinct therapeutic platform that warrants urgent re-evaluation. By leveraging the photonic disruption of viral genomes and simultaneous immunomodulation, UBI operates on principles governed by photochemical kinetics and hormetic dose-response relationships. This intervention employs ultraviolet light to directly inactivate circulating viral particles through nucleic acid photodamage while simultaneously reprogramming the host immune system—a "dual-strike" strategy that simultaneously reduces viral load and mitigates immunopathology. This stands in stark contrast to conventional antivirals, which solely target viral replication and can inadvertently spare the immunopathological cascade responsible for acute respiratory distress syndrome (ARDS) and fatal outcomes, especially in H5N1 infections. However, the authors emphasize that no direct experimental data on UBI against H5N1 currently exist in the peer-reviewed literature; this absence is a critical gap that the proposed research agenda seeks to address. The mechanistic foundation of UBI is rooted in well-established photochemical and photobiological principles, allowing for a quantitatively predictable and tunable therapeutic dose. This review synthesizes historical evidence, recent preclinical data, and the established safety profile of analogous extracorporeal phototherapy to build a case for UBI as a viable adjunctive treatment for severe influenza. While in vitro and animal model studies, including promising data against influenza, provide a compelling rationale, a critical gap exists in high-quality clinical research specific to influenza viruses, and the available animal data are preliminary, unreplicated, and derived from a single unpublished study. This work argues that the convergence of pandemic preparedness needs, the limitations of current antivirals, and UBI's unique mechanism positions it not as an alternative but as a necessary complementary strategy. We propose a focused research agenda beginning with in vitro dose-response studies against H5N1, progressing to optimized animal challenge models with independent replication, and culminating in human clinical trials, to definitively establish UBI's role in pandemic and severe seasonal influenza management.
β-Lactoglobulin (βLG) is considered among the most extensively researched ligand-binding proteins in food science research. Acridine Orange and Proflavin, which are recognized as prospective candidates of photosensitizer in photodynamic therapy, exist in protonated forms under the physiological conditions i.e. as AOH+ and PFH+ respectively. This study reports spectral and docking analyses to elucidate the binding of AOH+ and PFH+ with βLG. AOH+ perturbs the secondary structure of βLG more significantly compared to PFH+ as evident from circular dichroism spectroscopic study. Furthermore, fluorescence spectroscopic study suggests that the binding interaction is hydrophobic in nature and at a particular temperature AOH+ binds more strongly to βLG than PFH+. Ligand-induced steady-state fluorescence quenching of the tryptophanyl fluorescence of the protein shows an upward curvature for both AOH+ and PFH+ on Stern-Volmer analysis which is mainly attributed to the co-occurrence of static and dynamic quenching mechanisms. Moreover, the phenomenon of energy transfer is found to take place from the protein to the ligands. The binding parameters as well as the thermodynamic parameters involved in the binding interactions are evaluated using fluorescence spectroscopic data. Molecular docking suggests that both the ligands enter the hydrophobic beta-barrel region of the protein. The pronounced effect of AOH+ can be rationalized by the presence of the flanking methyl groups in AOH+ making it more hydrophobic than PFH+.
Cancer remains one of the leading causes of global mortality due to the uncontrolled proliferation of malignant cells. Although conventional treatments such as chemotherapy and immunotherapy have advanced, their associated adverse effects may compromise patients’ quality of life. In this context, photodynamic therapy (PDT) has emerged as a promising alternative, particularly through the use of natural photosensitizers such as curcumin. However, its clinical application is limited by low solubility and bioavailability, highlighting the need for efficient drug delivery systems. This scoping review included studies published between 2016 and 2024, complemented by an updated search covering studies from 2025 to early 2026. Literature searches were conducted in major databases (Embase®, Scopus®, PubMed®, Web of Science®, and ScienceDirect®). The analyzed studies demonstrate that nanostructured delivery systems significantly enhance the photodynamic performance of curcumin. Polymeric and hybrid systems provide improved control over drug release and photodynamic efficiency, whereas lipid-based systems offer advantages in biocompatibility and cellular uptake. These improvements are associated with the modulation of curcumin’s photophysical properties and increased generation of reactive oxygen species. Curcumin incorporation into nanocarriers such as nanoemulsions, liposomes, and polymeric nanoparticles represents a promising strategy for the treatment of various cancers. However, important challenges remain, including limited clinical evidence, variability in irradiation parameters, and barriers to large-scale production and standardization. Further in vivo and clinical investigations are required to validate therapeutic efficacy and support the clinical translation of curcumin-based photodynamic systems.
Sunscreens containing metal oxide particles as active ingredients are currently classified by the FDA as the only safe topical agents for protection of the skin against UV rays. Throughout the century-long history of sunscreens, many of their active ingredients have been proven unsafe after the period of commercial success, making the rigorous assessment of adverse side effects of sunscreens per se, including those based on metal oxides, imperative. In this study, zinc concentrations measured in water samples from nearly a dozen public swimming pools in the southern Californian city of Irvine were found to be directly proportional to the number of swimmers and peaked around midday, coinciding with the highest facility usage. Next, the zinc oxide phase was chemically isolated from a commercial sunscreen to study its interaction with the accompanying organic components using a series of microscopic and spectroscopic techniques, including SEM, EDX, NMR, FTIR and Raman spectroscopy. The aromatic and highly hydrophilic organic moieties, such as carboxylates, esters and silanes, were found to be most closely associated with the ZnO surface. Moreover, despite the sunscreen being neither soluble nor dispersible in water, the ZnO phase underwent evident morphological changes upon exposure to chlorinated swimming pool water. Photocatalytic assays demonstrated substantial production of reactive oxygen species (ROS) when the intact sunscreen and its isolated ZnO extract were exposed to short-wave or long-wave UV light, whereas the isolated organic phase produced no detectable ROS under the same conditions. ROS scavenging experiments identified superoxide anion radicals and hydrogen peroxide as the primary mediators of the observed photocatalytic activity. Curiously, the organic components of the sunscreen intensified the ROS generation by ZnO, possibly through facilitation of charge separation at the organic-ZnO interface. Oxidative stress augmentation relative to distilled water was also detected in swimming pool water, albeit only when its chlorination was carried out through electrochemical transformation of dissolved sodium chloride rather than by traditional chlorination methods. Reduced water column height separating the sunscreen layer from the UV light source additionally contributed to greater ROS production. The degradation kinetics were pseudo-first order for isolated ZnO but defied standard kinetic modeling upon introduction of the organic sunscreen components. Findings reported here cast a shadow on the universal safety attributed to today’s sunscreens utilizing metal oxide particles as active ingredients and suggest that research on amending the gold standards and state-of-the-art sunblock ointments must continue.
Sequential ultraviolet C (UVC) irradiation and photocatalytic treatment were investigated for Gram-positive bacteria using Lactobacillus casei as a biosafe and stress-tolerant model organism. Rapid and complete sterilization of Gram-positive bacteria remains an urgent challenge in human-made environments, where bacterial regrowth frequently compromises conventional disinfection strategies. Photocatalytic treatment was conducted using nano-sized magnetic TiO₂-SiO₂/Fe₃O₄ photocatalysts with high activity and facile magnetic separation. UVC irradiation alone failed to achieve complete sterilization due to bacterial regrowth, while photocatalytic treatment alone required prolonged irradiation times (>120 min). In contrast, the sequential combination achieved complete sterilization within a total of 50 min (10 min UVC irradiation and 40 min photocatalytic treatment). This reduction would arise from extensive UVC-induced DNA damage followed by reactive oxygen species–mediated disruption of DNA repair pathways and essential cellular functions, resulting in a repair-suppressed cellular state. This study establishes a new paradigm in disinfection of Gram-positive bacteria by demonstrating a repair-suppressed disinfection regime, in which bactericidal efficacy is governed not by the extent of primary damage but by the suppression of biological recovery pathways.
Photoelectrochemical (PEC) systems are rank among the most promising platforms for converting solar energy into storable fuels such as hydrogen, formate, and ammonia. Unlike suspension-based photocatalysis or photovoltaic-electrolysis hybrids, PEC devices integrate light absorption and catalytic conversion within a single architecture, offering unique advantages in system simplicity and cost potential. Yet despite impressive laboratory advances, widespread deployment of PEC remains limited by photovoltage deficits, sluggish reaction kinetics, materials instability, and the absence of standardized benchmarking protocols. This review provides a comprehensive overview of the state-of-the-art in PEC performance, organized by system architecture—ranging from single absorbers and PV-assisted tandems to monolithic artificial leaves. Key performance metrics are defined and compared across applications including water splitting, CO2 reduction, and paired organic/nitrate valorization. The review also outlines typical testing protocols and device configurations used in the field. Through this architecture- and metric-based perspective, we identify the critical trade-offs and technological bottlenecks that must be addressed to realize scalable, bias-free PEC fuel production.
This paper proposes a novel theoretical framework termed ''photometabolism'' to describe a hypothesized light-responsive, collagen-mediated bioenergetic system in human physiology. Integrating findings from disparate fields, including collagen biophysics, water chemistry, photobiology, and bioelectricity, evidence is synthesized suggesting that collagen-rich connective tissue may function as a distributed photoresponsive matrix capable of influencing cellular energy production. The proposed mechanism centers on three key elements: (1) collagen's established piezoelectric and proton-conductive properties, which enable charge transport along hydrated fibrils; (2) the unique behavior of interfacial water surrounding collagen, which facilitates proton relay via the Grotthuss mechanism; and (3) the demonstrated capacity of red and near-infrared light to penetrate tissue and modify both mitochondrial function and interfacial water properties. The hypothesis presented here is that when light interacts with the collagen-water matrix, it biases proton distributions and charge separation in ways that reduce the energetic burden on mitochondria, effectively supplementing conventional food-based metabolism. This framework does not claim that humans photosynthesize; rather, it proposes that light energy converts into favorable bioelectric conditions supporting ATP synthesis. The mechanism is distinguished from established photobiomodulation pathways while noting their complementary nature. The hypothesis generates specific testable predictions regarding illumination-dependent changes in tissue electrical properties, metabolic efficiency of cells adjacent to illuminated collagen, and dose-dependent effects on bioelectric-dependent processes. If validated, this framework has implications for understanding chronic fatigue, indoor lifestyle-related metabolic dysfunction, and potential therapeutic applications of light exposure.
The indiscriminate discharge and leakage of waste motor oil (WMO), enriched with heavy metals, polycyclic aromatic hydrocarbons (PAHs), and other persistent organic contaminants, constitute a major and persistent source of environmental pollution, severely threatening soil quality, ecosystem integrity, and sustainable agricultural productivity. The present study examines how WMO contamination alters soil physicochemical properties, seed germination, root morphological characteristics, and key biochemical and physiological processes associated with photosynthetic functioning in Trigonella foenum-graecum. Soil analysis revealed a significant decline in pH and total nitrogen following WMO application, accompanied by increased electrical conductivity and total organic carbon, indicating disruption of soil chemical equilibrium and nutrient dynamics. These edaphic alterations were reflected in substantial reductions in germination percentage, root length, and nodule number per plant, indicating impaired early plant establishment and root development. At the biochemical level, chlorophyll content declined significantly, suggesting reduced photosynthetic capacity. Antioxidant enzymes (SOD, CAT, and POD) exhibited biphasic concentration-dependent responses, indicating oxidative imbalance and limited efficiency of reactive oxygen species detoxification under elevated WMO stress. A marked increase in malondialdehyde (MDA) further confirmed enhanced lipid peroxidation and membrane damage. Distortions in the OJIP chlorophyll a fluorescence transients provided mechanistic evidence of WMO-induced impairment of photosystem II (PSII). WMO exposure caused partial deactivation of reaction centres (↓RC/CSm), reduced absorption (↓ABS/CSm) and trapping fluxes (↓TRo/CSm), and inhibited electron transport beyond QA (↓ETo/CSm; ↓ΦEo), accompanied by reduced maximum quantum yield (↓ΦPo). Increased energy dissipation (↑Kn; ↑ΦDo) and strong declines in performance indices (↓PI; ↓SFIabs) confirmed PSII destabilization. Overall, WMO contamination deteriorates soil quality and disrupts plant growth, antioxidant balance, and PSII-mediated photosynthesis, highlighting its ecological risk and the urgent need for effective remediation to ensure soil health and sustainable crop productivity.
This study reports the photosensitizing properties of the dyad [Ru(phen)₂(pNDIp)]²⁺ (RupNDIp; phen = 1,10-phenanthroline; pNDIp = naphthalene-functionalized phenanthroline ligand) for photodynamic therapy (PDT) applications in phosphate-buffered saline (PBS). RuPNDIp displays broad and intense absorption in the UV-Vis region, along with strong emission at 600 nm from its 3MLCT state, minimizing reabsorption and spectral overlap with endogenous biomolecules. The dyad efficiently generates singlet oxygen (1O2) in PBS and retains its activity through at least three consecutive 30 minutes irradiation cycles (200 mW·cm-2) without photobleaching. In model membranes (POPC:DOPG), RupNDIp functions as a bright luminescent probe and, under continuous 450 nm irradiation, induces membrane disruption, demonstrating its integrated imaging and therapeutic capabilities. Because membrane damage strongly enhances PDT outcomes, the ability to obtain luminescent images revealing the localization of the dyad in membranes is particularly important. The antimicrobial activity of RuPNDIp was evaluated against Escherichia coli (ATCC 25922). RupNDIp showed modest dark cytotoxicity at 25 μM, likely arising from electrostatic interactions and partial membrane uptake; however, upon 450 nm LED irradiation (7 J·cm⁻2), it induced a pronounced photocytotoxic effect, reducing E. coli viability by 4.99 log10, highlighting its potential as a membrane-targeted photosensitizer for antimicrobial photodynamic therapy.
Visible light-driven nitro-Mannich reaction using graphitic carbon nitride (g-C3N4) photocatalyst addresses significant environmental issues caused by traditional synthesis routes that often involve toxic reagents and harsh conditions. g-C3N4 was synthesized via thermal polymerization of urea and dicyandiamide precursors at different temperatures (260°C, 360°C, 460°C, and 560°C). Among these, g-C3N4 synthesized at 460°C under 200 W white LED demonstrated the best catalytic performance, achieving excellent conversion of 98.06% and selectivity of 90.50% in the reaction. The synthesized g-C3N4 samples were thoroughly characterized by FTIR, XRD, XPS, FE-SEM, HR-TEM, UV-DRS, EIS, and Mott-Schottky analyses to confirm the structure, morphology, optical properties, and electrochemical characteristics of the catalyst. The photocatalyst demonstrated promising reusability, maintaining its activity through five consecutive reaction cycles, highlighting its potential for sustainable and environmentally friendly organic synthesis applications. This approach offers a green alternative to conventional nitro-Mannich reactions with visible light photocatalysis over metal-free g-C3N4 catalysts.
This study aimed to evaluate the histological and molecular effects of polychromatic photobiomodulation (PBM, 600–1200 nm), delivered at varying treatment frequencies, on wound healing in a streptozotocin (STZ)-induced diabetic rat model. To minimize inter-subject variability, three full-thickness excisional wounds were created on the dorsum of each diabetic rat and assigned to one of three groups: untreated Negative Control (NC), once-daily PBM (PBM1), or twice-daily PBM (PBM2). Treatments were administered using a polychromatic light source (600–1200 nm) placed 30 cm away from the wounds at an irradiance of 0.038 W/cm² with escalating fluences over a six-day period. Skin samples were harvested on Days 7 and 14 post-wounding and analyzed using Masson’s Trichrome staining and immunohistochemistry for VEGF, VEGFR2, TGF-β, TGF-βR2, CD163, and TNF-α. The PBM2 regimen significantly enhanced re-epithelialization, collagen deposition, and angiogenesis compared to both PBM1 and untreated controls. Immunohistochemical analysis demonstrated early and pronounced expression of VEGF and CD163, along with sustained activation of TGF-βR2 in the PBM2 group. TNF-α expression was significantly reduced, particularly in the PBM2-treated wounds, suggesting accelerated resolution of inflammation and enhanced M2 macrophage polarization. Masson’s Trichrome staining further confirmed the presence of denser and more organized collagen fibers in PBM2-treated wounds. Collectively, these findings indicate that twice-daily polychromatic PBM facilitates diabetic wound healing through synergistic pro-angiogenic, anti-inflammatory, and fibroproliferative pathways. This study supports the further optimization of PBM protocols for the effective management of chronic wounds.
The photophysical properties of 4-aminophthalimide (4-AP) were investigated in reverse micelles formed by sodium 1,4-bis(2-ethylhexyl) sulfosuccinate (AOT) using two biocompatible solvents, isopropyl myristate (IPM) and methyl laurate (ML), as the continuous phase. Absorption and fluorescence spectroscopy were employed to analyze the influence of surfactant concentration and water content (W0 = [water]/[AOT]) on the microenvironment sensed by the probe. A bathochromic shift in both absorption and emission bands were observed with increasing AOT concentration, indicating that 4-AP resides in increasingly polar environments. Red-edge excitation experiments revealed restricted interfacial dynamics, and in the IPM/AOT/water system, the emergence of an additional emission band suggests the formation of an intramolecular charge-transfer (ICT) excited-state species. Partition constants (Kp) between the micellar interface and external solvent were determined, showing that water enhances probe incorporation and polarity at the interface. The comparison with benzene and n-heptane systems underscores the potential of biocompatible solvents as sustainable media to mimic organized microenvironments for photophysical and biochemical studies.
