Search Results (753)

Cyanobacteria are a prolific source of bioactive metabolites with expanding applications in sustainable agriculture and biotechnology. This work explores, for the first time in thermotolerant Colombian isolates, the impact of light spectrum, photoperiod, and irradiance on the co-production of exopolysaccharides (EPS) and indole-3-acetic acid (IAA). Six strains from hot-spring environments were screened under varying blue:red (B:R) LED ratios and full-spectrum illumination. Hapalosiphon sp. UFPS_002 outperformed all others, reaching ~290 mg L⁻¹ EPS and 28 µg mL⁻¹ IAA in the initial screen. Response-surface methodology was then used to optimize light intensity and photoperiod. EPS peaked at 281.4 mg L⁻¹ under a B:R ratio of 1:5 LED, 85 µmol m⁻² s⁻¹, and a 14.5 h light cycle, whereas IAA was maximized at 34.4 µg mL⁻¹ under cool-white LEDs at a similar irradiance. The quadratic models exhibited excellent predictive power (R² > 0.98) and a non-significant lack of fit, confirming the light regime as the dominant driver of metabolite yield. These results demonstrate that precise photonic tuning can selectively steer carbon flux toward either EPS or IAA, providing an energy-efficient strategy to upscale thermotolerant cyanobacteria for climate-resilient biofertilizers, bioplastics precursors, and other high-value bioproducts. Full article

Background: Blue light (BL) irradiation has been shown to induce photobiomodulation (PBM) in cells. Here, we investigate its influence on cell types involved in wound healing. Methods: Cellular responses of immortalized human keratinocytes (HaCaTs), normal human dermal fibroblasts (NHDFs), and human umbilical vein endothelial cells (HUVECs) after light treatment at 450 nm were analyzed by kinetic assays on cell viability, proliferation, ATP quantification, migration assay, and apoptosis assay. Gene expression was evaluated by transcriptome analysis. Results: A biphasic effect was observed on HaCaTs, NHDFs, and HUVECs. Low-fluence (4.5 J/cm²) irradiation stimulated cell viability, proliferation, and migration. mRNA sequencing indicated involvement of transforming growth factor beta (TGF-β), ErbB, and vascular endothelial growth factor (VEGF) pathways. High-fluence (18 J/cm²) irradiation inhibited these cellular activities by downregulating DNA replication, the cell cycle, and mismatch repair pathways. Conclusions: HaCaTs, NHDFs, and HUVECs exhibited a dose-dependent pattern after BL irradiation. These findings broaden the view of PBM following BL irradiation of these three cell types, thereby promoting their potential application in wound healing and angiogenesis. Our data on low-fluence BL at 450 nm indicates clinical potential for a novel modality in wound therapy. Full article

Photodynamic inactivation (aPDI) involves the interaction of three components: non-toxic photosensitizer molecules (PS), low-intensity visible light, and molecular oxygen. This interaction leads to the generation of toxic reactive oxygen species. The present work demonstrated the efficacy of light-induced antimicrobial photodynamic inactivation against Pseudomonas aeruginosa and Pseudomonas putida using 5-aminolevulinic acid (5-ALA) as a prodrug to produce the photosensitizer protoporphyrin IX. The photoeradication efficiency of these pathogens under blue (405 nm; 45 mW cm⁻²) and red (635 nm; 53 mW cm⁻²) light was investigated. Results showed that at least 30 min of blue light irradiation was necessary to achieve a 99.999% reduction of P. aeruginosa, whereas red light was less effective. P. putida exhibited limited susceptibility under similar conditions. To enhance aPDI efficiency, exogenous glucose was added alongside 5-ALA, which significantly increased the photodynamic efficacy—particularly against P. aeruginosa—leading to complete eradication after just 5 min of exposure. Spectroscopic analyses confirmed that glucose increased the levels of protoporphyrin IX, which correlated with enhanced photodynamic efficacy. Furthermore, multiple aPDI exposure reduced key virulence factors, including alkaline protease activity, biofilm formation, and swarming motility (in P. aeruginosa). These findings suggest that 5-ALA-mediated photodynamic inactivation offers a promising strategy to improve efficacy against resistant Gram-negative pathogens. Full article

In this study, the BPTCD/g-C₃N₄ heterojunction photocatalyst was successfully prepared by the hydrothermal method. BPTCD (3,3′,4,4′-benzophenone tetracarboxylic dianhydride) is immobilised on the surface of g-C₃N₄ by non-covalent π-π stacking. The BPTCD/g-C₃N₄ heterojunction photocatalyst is an all-organic photocatalyst with significantly improved photocatalytic performance compared with g-C₃N₄. BPTCD/g-C₃N₄-60% was able to effectively degrade MO solution (10 mg/L) to 99.9% and 82.8% in 60 min under full spectrum and visible light. The TOC measurement results indicate that MO can ultimately be decomposed into H₂O and CO₂ through photocatalytic action. The photodegradation of methyl orange by BPTCD/g-C₃N₄ composite materials under sunlight is mainly attributed to the successful construction of the heterojunction structure and its excellent π-π stacking effect. Superoxide radicals (^•O₂⁻) were found to be the main active species, while ^•OH and h⁺ played a secondary role. The synthesised BPTCD/g-C₃N₄ also showed excellent stability in the activity of photodegradation of MO in wastewater, with the performance remaining above 90% after three cycles. The mechanism of the photocatalytic removal of MO dyes was also investigated by the trap agent experiments. Additionally, BPTCD/g-C₃N₄-60% demonstrated exceptional photodegradation performance in the degradation of methylene blue (MB). BPTCD/g-C₃N₄ heterojunctions have great potential to degrade organic pollutants in wastewater under solar irradiation conditions. Full article

To investigate the application potential of amorphous transition metal chalcogenides in catalysis, this study successfully synthesized amorphous molybdenum telluride (MoTe_x) materials and systematically explored their structural characteristics, compositional modulation, and catalytic performance. Experimental results indicate that the synthesized amorphous system consists of particles of approximately 200–300 nm in size. This distinct microstructure facilitates the exposure of abundant active sites and enhances physical adsorption capacity. The amorphous MoTe₂/MoTe₃ catalysts achieve an approximately 30%/40% degradation of methylene blue (MB) within 90 min, demonstrating significantly enhanced photocatalytic efficiency compared to that of crystalline MoTe₂ (≈20% degradation under identical conditions). Furthermore, when integrated with titanium dioxide (TiO₂), the composite exhibits exceptional co-catalytic performance, achieving a 90% degradation of MB within 90 min under visible-light irradiation, representing a catalytic efficiency improvement exceeding 160% compared to the results for pristine TiO₂. Furthermore, through comparative analysis of the catalytic behavior and microstructural variations between amorphous MoTe₃ (a-MoTe₃) and MoTe₂ (a-MoTe₂), we observed that the catalytic activity of molybdenum tellurides exhibits a weak correlation with the tellurium content, with co-catalytic efficacy jointly governed by the density of the active sites and the physical adsorption properties. This research provides new methods and insights for the study and improvement of catalytic performance in chalcogenide materials. Full article

In this study, chromium ferrite (FeCr; CrFe₂O₄) nanoparticles supported on activated carbon (AC), obtained from agricultural olive mill solid waste, were synthesized via a simple hydrothermal process. The structural, morphological, optical, and chemical properties of the FeCr/AC composite were characterized using XRD, SEM, EDX, DRS, BET, and FTIR techniques. The FeCr/AC composite was applied as a heterogeneous photo-Fenton catalyst for the degradation of methylene blue (MB) dye in an aqueous solution under 25 W visible-light LED irradiation. Critical operational factors, such as FeCr/AC dosage, pH, MB concentration, and H₂O₂ levels, were optimized. Under optimal conditions, 97.56% of MB was removed within 120 min of visible-light exposure, following pseudo-first-order kinetics. The composite also exhibited high efficiency in degrading methyl orange dye (95%) and tetracycline antibiotic (88%) within 180 min, with corresponding first-order rate constants of 0.0225 min⁻¹ and 0.0115 min⁻¹, respectively. This study highlights the potential of FeCr/AC for treating water contaminated with dyes and pharmaceuticals, in line with the Sustainable Development Goals (SDGs) for water purification. Full article

Free-standing copper oxide (Cu₂O)-copper hydroxide (Cu(OH)₂) nanocomposites with enhanced catalytic and antibacterial functionalities were synthesized on copper mesh using a green method based on spinach leaf extract and glycerol. EDX, SEM, and TEM analyses confirmed the chemical composition and morphology. The resulting Cu2O-Cu(OH)₂@Cu mesh exhibited notable hydrophobicity, achieving a contact angle of 137.5° ± 0.6, and demonstrated the ability to separate thick oils, such as HD-40 engine oil, from water with a 90% separation efficiency. Concurrently, its photocatalytic performance was evaluated by the degradation of methylene blue (MB) under a weak light intensity of 5 mW/cm², achieving 85.5% degradation within 30 min. Although its application as a functional membrane in water treatment may raise safety concerns, the mesh showed significant antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria under both dark and light conditions. Using the disk diffusion method, strong bacterial inhibition was observed after 24 h of exposure in the dark. Upon visible light irradiation, bactericidal efficiency was further enhanced—by 17% for S. aureus and 2% for E. coli. These findings highlight the potential of the Cu₂O-Cu(OH)₂@Cu microfibers as a multifunctional membrane for industrial wastewater treatment, capable of simultaneously removing oil, degrading organic dyes, and inactivating pathogenic bacteria through photo-assisted processes. Full article

In the present study, a photodegradation technique was employed for the removal of methylene blue dye from aqueous solution using a tungsten oxide-based photocatalyst. The photocatalyst was synthesized via a green synthesis route utilizing a plant extract (PE) under acidic conditions. The synthesized photocatalyst was characterized by various spectroscopic and microscopic techniques that confirmed the presence of various functional groups on the catalyst surface and revealed a narrow bandgap of ~3.0 eV. The synthesized particles exhibited a nanoscale dimension ranging from 10 to 15 nm. The photocatalytic activity of the material was evaluated under ultraviolet light, visible light, and sunlight irradiation, demonstrating the efficient degradation of methylene blue under all light sources. Furthermore, catalysis reusability studies indicated excellent stability, with consistent photocatalytic performance observed after five successive cycles. Full article

The effect of white and additional red and blue LED lighting at night (Blue-NLL, Red-NLL) and during the pre-harvest period (Blue-P-hLL, Red-P-hLL) on morphological and physiological parameters, elemental composition, content of polyphenols, and essential oils of purple basil cultivars ‘Ararat’ and green basil ‘Tonus’ grown in the hydroponic conditions of the climatic chamber was studied. The height of the plants was determined by the variety and the LED irradiation period. The highest purple basil plants were obtained in the variant with Blue-NLL illumination; the highest green basil plants were obtained under Blue-P-hLL and Red-P-hLL. The red spectrum, regardless of the lighting period and variety, increased the area and number of leaves, biomass, and vegetative productivity. Significant changes in the elemental composition of the vegetative mass of basil varieties were determined by the period of exposure to the red spectrum. Red-P-hLL stimulated the absorption and accumulation of Mg, Ca, S, and P from the nutrient solution, and Red-P-hLL reduced the nitrate content by more than 30.00%. Blue-NLL lighting increased the content of quercetin, rosmarinic acid, and essential oil and reduced the nitrate content in the vegetative mass by more than 40.00%. The effectiveness of the white LED was observed in increasing the vegetative mass of ‘Tonus’. The results of this study will be in demand in the real sector of the economy when improving resource-saving technologies for growing environmentally friendly leafy vegetable crops with improved chemical composition and high vegetative productivity. Full article

This study investigates near-infrared (NIR)-induced, Phyto-enhanced, second harmonic generation-mediated photodynamic therapy (Phyto-SHG-PDT) using barium titanate (BT)/rhein/polyethylene glycol 100 (PEG100) and BT/Yemenite “Etrog” leaf extract/PEG100 nanoconjugates. We compare continuous-wave (CW), multi-line Argon-ion laser illumination in the NIR range with high-peak-power femtosecond (fs) 800 nm pulses. Under CW NIR light, BT/rhein nanoconjugates reduced PC3 prostate cancer cell viability by 18% versus non-irradiated controls (p < 0.05), while BT/extract nanoconjugates exhibited 15% dark toxicity. The observed SHG signal matched theoretical predictions and previous CW laser studies. Reactive Oxygen Species (ROS) scavenger 1,3-diphenyl-isobenzofuran (DPBF) showed reduced absorbance at 410 nm upon NIR illumination, indirectly supporting SHG emission at 400 nm from nanoconjugates. Under fs-pulsed laser exposure, pronounced two-photon absorption (TPA) and SHG effects were observed in both nanoconjugate types. Our results demonstrate the effectiveness of BT/rhein nanoconjugates under both laser conditions, while the BT/extract nanoconjugates benefited from high-power pulsed excitation. These results highlight the potential of BT-based Phyto-SHG-PDT nanoconjugates for NIR and blue light applications, leveraging nonlinear optical effects for advanced photochemical cancer therapies. Full article

Recently, the urgency of combating antibiotic-resistant bacteria, viruses, and other pathogens has dramatically increased. With the development of nanotechnology, significant hopes are placed on nanoparticles with antimicrobial properties. The efficiency of such materials can be significantly enhanced through light-activated processes. In this study, we prepared composite ZnO-Ag nanoparticles and tested their ability to inhibit Staphylococcus aureus bacteria. The composite ZnO-Ag nanoparticles were fabricated using pulsed laser ablation of Zn and Ag targets in water using a nanosecond pulsed laser. During antibacterial tests, light-enhanced activation of the nanoparticles was achieved using low-power near UV (375 nm) and blue visible (410 nm) LED irradiation. For comparison, similar laser-fabricated ZnO nanoparticles were also tested. The combined use of nanoparticles and LED irradiation significantly increased the generation of reactive oxygen species. As a result, low nanoparticle concentrations (0.05 g/L) and low-power LED irradiation (0.17–0.22 W) significantly reduced the concentration of Staphylococcus aureus bacteria, including experiments with visible light irradiation. Compared to their ZnO counterparts, the use of ZnO-Ag composite particles led to an additional increase in antimicrobial activity. Full article

The synthesis of graphitic carbon nitride (g-C₃N₄) coupled with tin sulfide (SnS) has been identified as an effective method for improving the photocatalytic and electrochemical performance of SnS, a promising material for environmental and energy-related applications. In this study, we focused on how g-C₃N₄ influences the structural, optical, electrochemical, and functional properties of SnS. XRD and FTIR confirmed the formation of SnS/g-C₃N₄ heterostructure, while surface morphology analysis by SEM showed proper dispersion of SnS particles over g-C₃N₄ with a good interface contact. The SnS/g-C₃N₄ composite itself demonstrated improved photocatalytic performance, with the degradation rate of methylene blue reaching approximately 94% under visible light irradiation compared to the moderate activity of SnS. This enhancement can be credited to the successful charge carrier separation enabled by the type II heterojunction created between SnS and g-C₃N₄. Moreover, the composite presented improved electrochemical activity with a specific capacitance of 1340 F·g⁻¹ at a scan rate of 10 A·g⁻¹ and good cycling stability, where the capacitance was 92% after 5000 cycles. As such, these SnS/g-C₃N₄ composites suggest the specific application of this class of material in photocatalytic degradation as well as energy storage, putting forward new effective resolutions to environmental and energy issues. Full article

The adjunctive use of antimicrobial photodynamic therapy (aPDT) has been investigated as a promising approach to enhance periodontal therapy. Methylene blue (MB) is the most commonly used photosensitizer due to its favorable characteristics, including a neutral pH and an absorption peak at 660 nm. Due to the considerable heterogeneity among studies and the lack of well-established clinical protocols, this study aims to conduct an integrative review to highlight the effects of MB-mediated aPDT as an adjunct to periodontal treatment. The inclusion criteria were randomized clinical trials that used MB as the PS, published between 2009 and 2024, with a minimum follow-up of three months. Studies included patients with periodontitis treated with SRP alone or in combination with aPDT. Of the 237 studies initially identified, 23 met the eligibility criteria and were included in this integrative review. The risk of bias was evaluated using the Cochrane criteria for randomized controlled trials. Although the included studies reported heterogeneous clinical outcomes, a general trend toward improvement in key periodontal parameters—probing depth, bleeding on probing, clinical attachment level, and plaque index—was observed when MB-mediated aPDT was used as an adjunct to conventional periodontal treatment. However, substantial variability in clinical protocols—including differences in photosensitizer concentration, type of light source, irradiation time, and frequency of application—limited the comparability of results across studies. Despite these methodological inconsistencies, current evidence suggests that MB-mediated aPDT holds promise as an adjunctive approach in periodontal therapy. Nevertheless, due to the clinical heterogeneity and the limited number of studies with long-term follow-up, its overall efficacy remains inconclusive. Further well-designed randomized controlled trials with standardized protocols and subgroup analyses are essential to validate its clinical relevance. Full article

In this study, the surface photocatalytic activity of an anatase–titanium oxide (TiO_x) film was modified by a thin copper (Cu) layer with the subsequential oxidation annealing process. Through this simple annealing process, the photocatalytic activity of the TiO_x/Cu structure to decompose the methylene blue solution and inhibit the growth of Escherichia coli. could be optimized. With the help of a study on the conductive type required for the oxidation of a single Cu layer, an n/p nanocomposite heterojunction was realized, as this contact system anneals at temperatures of 350 °C and 450 °C. An extra electrical field at the contact interfaces that was be beneficial for separating the photo-generated electron–hole pairs (EHPs) under UV light irradiation was built. The built-in electrical field led to an increase in the structural photocatalytic activity. Moreover, as the p-type cuprous oxide (p-Cu₂O) structure oxidized by the annealed Cu layer could provide a high conduction band that is offset when in contact with the TiO_x film, the photogenerated EHPs on the TiO_x surface could be separated more effectively. Accordingly, the 350 °C-annealed sample, abundant in the nanocomposite TiO_x/Cu₂O heterojunction which could significantly retard the recombination of photo-generated carriers, corresponded to an increase of about 38% in the photocatalytic activity as compared with the single TiO_x film. Full article

The synthesis of cellulose extracted from agricultural waste, specifically almond and fig tree trimmings, and its combination with ZnO nanoparticles to form cellulose/ZnO composites was studied. These adsorbents/photocatalysts were fully characterized, confirming not only the effective deposition of zinc oxide nanoparticles on the cellulose surface but also the improvement in homogeneity and lower agglomeration and size of ZnO particles grown on these fibers (crystallites were 43 ± 12 nm for pristine ZnO and 13–26 nm for composites). The efficacy of these composites was evaluated against methylene blue (MB), methyl orange (MO), and bromophenol blue (BB), this study being the first time that BB removal results have been reported using dual photo-adsorptive cellulosic composites. After 20 min, removals of approximately 45% were achieved for the anionic dyes MO and BB under UV light and up to 65% for MB with either applied radiation, indicating a clear adsorption mechanism for this cationic dye. A reusability study was conducted for the BB removal system, with only a 15–19% loss in BB removal capacity under UV irradiation after the third reuse. These results demonstrated the potential and efficiency of cellulose/ZnO composites as promising photocatalysts for textile wastewater treatment, providing a sustainable and interesting approach to mitigate dye pollution. Full article