Search Results (5,155)

Photodynamic therapy (PDT) exploits photoactivated materials that generate reactive oxygen species (ROS) to induce selective cancer cell death. Nitrogen-doped carbon dots (N-CDs) have emerged as promising photosensitizers owing to their favorable optical properties, while hybridization with titanium dioxide (TiO₂) may further enhance photoinduced ROS generation through improved charge separation. Here, we synthesized a series of N-CD/TiO₂ hybrid composites with varying TiO₂ content using a hydrothermal approach and systematically investigated the relationship between their physicochemical characteristics and biological activity. The hybrid materials were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, dynamic light scattering, and UV–visible spectroscopy. Among the formulations investigated, the composite containing 90% N-CDs and 10% TiO₂ (N-CDs10T) exhibited the smallest hydrodynamic diameter, a relatively narrow particle size distribution, favorable optical properties, and the strongest irradiation-dependent biological responses. Biological activity was evaluated in A549 lung adenocarcinoma and Kelly neuroblastoma cells. Under dark conditions, all formulations displayed relatively low intrinsic cytotoxicity. Following irradiation with 365 nm UVA light, however, N-CDs10T induced a marked increase in intracellular ROS production, activation of antioxidant response element (ARE)-dependent signaling, disruption of cell-cycle progression, apoptosis-associated cell death, and inhibition of cell proliferation and migration. Kelly cells exhibited greater sensitivity than A549 cells, with IC₅₀ values decreasing from 0.98 mg/mL under dark conditions to 0.52 mg/mL following irradiation. Collectively, these findings demonstrate that N-CD/TiO₂ hybrid composites function as photoresponsive materials that enhance ROS-mediated cytotoxicity upon light activation. Beyond demonstrating phototoxicity, this study systematically links hybrid composition with oxidative stress signaling and multiple cellular responses, providing a comprehensive biological evaluation of N-CD/TiO₂ hybrid materials. While additional studies are required to identify the predominant ROS, evaluate selectivity in non-malignant cells, and optimize activation at clinically relevant wavelengths, the present work establishes a proof of concept for the development of N-CD/TiO₂ hybrid composites for photodynamic applications. Full article

Objective: The aim of this systematic review was to evaluate the in vitro effects of LED-based photobiomodulation on fibroblasts and osteoblasts, with particular focus on cellular processes involved in soft- and hard-tissue regeneration. Methods: A comprehensive electronic search was conducted on 3 April 2026 in PubMed, Scopus, Web of Science, Embase, and WorldCat according to PRISMA guidelines. The analyzed outcomes included cell viability, proliferation, migration, collagen synthesis, oxidative stress, mitochondrial activity, and selected regeneration-related processes. A total of 745 records were initially identified, and 32 studies met the inclusion criteria and were included in the qualitative synthesis. Results: The biological effects of LED-PBM depended strongly on irradiation parameters, including wavelength, fluence, irradiance, exposure time, treatment schedule, and the initial condition of the cells. Most included studies focused on fibroblast models. Red and near-infrared light showed the most consistent beneficial effects, particularly by supporting fibroblast viability, proliferation, migration, mitochondrial activity, ATP production, collagen-related responses, and oxidative stress modulation. In osteoblast-related models, LED irradiation showed potential to influence cell number, metabolic activity, maturation markers, and mineralization-related outcomes; however, the number of studies was limited. Blue light demonstrated dose-dependent effects, with higher fluences reducing fibroblast metabolic activity, proliferation, or viability. Green light improved fibroblast proliferation and migration in one model but was associated with increased cell death in osteoblast-like cells. Conclusion: LED-PBM may positively modulate cellular processes involved in soft- and hard-tissue regeneration in vitro. However, the observed effects are strongly parameter-dependent, and further standardized studies are required to define optimal irradiation protocols and validate their potential clinical relevance. Full article

Femtosecond laser processing enables spatially controlled modification of the structure, composition, and functionality of advanced materials through highly localized energy deposition and laser–matter interaction mechanisms. This review discusses the role of ultrafast laser irradiation in the engineering of oxide-based functional systems, including functional oxides, oxide-containing layers, interfaces, and heterogeneous structures whose properties are substantially determined by an oxide component. The mechanisms governing laser-induced oxidation, phase transformation, elemental redistribution, defect generation, and hierarchical micro-/nanostructure formation are considered. Particular attention is given to the ability of femtosecond laser processing to create surfaces with tailored interactions with light, liquids, biological environments, and external stimuli, enabling responsive devices and advanced manufacturing strategies. Laser-modified oxide layers and nanostructured interfaces are analyzed as pathways for controlling surface energy, optical properties, chemical activity, and functional response. The relationship between laser-generated architectures and their applications in sensing, actuation, wetting control, and multifunctional systems is discussed. By connecting ultrafast laser surface engineering with emerging 4D manufacturing concepts, this review highlights femtosecond laser technologies as a versatile platform for designing systems with spatially programmed functionality and, where stimulus-dependent behavior is demonstrated, time-dependent performance. Such approaches provide opportunities for integrating adaptive oxide-based functional systems into advanced manufacturing. Full article

In the present research, the application of a photocatalytic reactor operated under simulated solar-light-assisted air gap membrane distillation (AGMD) is proposed to remove ketoprofen from seawater. TiO₂ at a concentration of 1 g/L, containing sulfur, was applied as a photocatalyst. The AGMD process was carried out under a feed temperature of 60–80 °C and a membrane area of 131 cm² during long-term operation. Simulated solar light was applied as an irradiance source. At the first stage of the process, the feed was concentrated for 73 h, and after that, the solution of seawater spiked with ketoprofen was photocatalytically treated for 96 h. Based on the experiments, it was found that 51% of ketoprofen was removed after the solar-driven photocatalysis process. Pure distillate without salts (conductivity below 2 µS/cm) and ketoprofen were obtained after 73 h. The performance of the membrane exhibited ca. two times higher permeate flux at an operation temperature of 80 °C in comparison with 60 °C, i.e., 24.7 L/h·m² and 47.3 L/h·m², respectively. Despite the presence of small deposits on the membrane surface, no membrane wetting was observed. The concentration of ketoprofen in the concentrates during the AGMD process and solar-driven photocatalysis can remove this pharmaceutical even from matrices enriched with salts (high AGMD concentrate), with good efficiency. Full article

This study reports the synthesis and comprehensive characterization of a novel 5% cadmium-doped cerium oxide/reduced graphene oxide (5% Cd-CeO₂/rGO) nanocomposite for the enhanced visible-light-driven photocatalytic degradation of methyl orange (MO). The nanocomposite was prepared using a simple co-precipitation method followed by thermal reduction, which integrates the excellent electron-transport properties of reduced graphene oxide (rGO) with the oxygen-vacancy-rich characteristics of Cd-doped CeO₂, resulting in improved photocatalytic performance. The successful synthesis of the nanocomposite and the direct interaction between the rGO sheets and ultrafine CeO₂ nanoparticles were verified through structural and morphological analyses using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). XPS results indicated an increase in the Ce³⁺ concentration and oxygen vacancy density after Cd doping and rGO incorporation, both of which play a crucial role in enhancing photocatalytic activity. Under visible-light irradiation, the 5% Cd-CeO₂/rGO nanocomposite exhibited substantially higher photocatalytic activity and methyl orange (MO) degradation efficiency than pristine CeO₂ and reduced graphene oxide (rGO). The improved photocatalytic performance demonstrates the beneficial role of combining metal-ion doping with conductive carbon supports to facilitate charge separation and electron transport in semiconductor photocatalysts. The developed nanocomposite also shows promising potential for the design of next-generation semiconductor-based materials for photocatalytic, energy conversion, and optoelectronic applications. Full article

In this work, we aim to enhance the photocatalytic performance of SrTiO₃ by constructing a heterojunction with photoactive BiOBr. The novelty of this study lies in demonstrating the dual functionality of the SrTiO₃/BiOBr heterojunction in both photocatalytic tetracycline degradation and antibacterial applications and correlating its performance with its interfacial electronic properties. A SrTiO₃/BiOBr (50STO) heterojunction was successfully synthesized by combining microwave-assisted sol–gel-derived SrTiO₃ with co-precipitated BiOBr via solid-state calcination. XRD analysis revealed that the synthesized composite consisted of crystalline cubic SrTiO₃ and tetragonal BiOBr, confirming the successful formation of a 50STO heterojunction while preserving the crystal structures of both components. PL and EIS analyses revealed modified charge-carrier behavior, further supporting the successful formation of the 50STO heterojunction. XPS confirmed the chemical states of the constituent elements and revealed changes in the surface chemical environment following the coupling of SrTiO₃ with BiOBr. SEM, elemental mapping, and UV–Vis DRS analyses demonstrated uniform elemental distribution, enhanced visible-light absorption, suppressed electron–hole recombination, and improved interfacial charge transfer. Consequently, the optimized 50STO composite achieved 45% tetracycline degradation under visible-light irradiation within 150 min, whereas pristine SrTiO₃ degraded only 2%. The apparent reaction rate constant increased from 6.11 × 10⁻⁷ to 3.2 × 10⁻³ min⁻¹, while the heterojunction remained stable over five reuse cycles. Radical scavenging and LC–MS analyses identified h⁺ and •OH as the dominant reactive species and revealed successive tetracycline degradation. The composite also exhibited excellent antibacterial activity against E. coli under white-light irradiation. Full article

Light fidelity (LiFi) is progressively evolving as a highly promising communication technology because of its unique benefits, available spectrum, low implementation costs, and adaptive beamforming capabilities. Despite their advantages, existing LiFi networks remain constrained by limited data rates, coverage area, and information security in practical environments. Therefore, a high-speed, high-capacity, and secure quantum key distribution (QKD)-assisted integrated multi-wavelengths (450/532/620 nm) LiFi system using mode division multiplexing (MDM) is proposed. The results demonstrate that the proposed system achieves maximum transmission distances of 20.5–22 m and 19–22 m using different Laguerre–Gaussian (LG) and Hermite–Gaussian (HG) mode indices {[0,0], [0,10], [0,20], [0,30]}, at an aggregate data rate of 40 Gbps. Furthermore, the minimum acceptable transmitter angles of 30–90° for irradiance angles of 20–80° are required to maintain the target bit error rate (BER) of 10⁻⁹. The minimum photodetector detection areas required at transmission distances of 20–30 m are 1–2 cm² at the minimum BER limit. Moreover, the proposed system exhibits optimum performance, achieving an optical loss of −39.47 dB, −49.03 dBm received power, and 45.39 dB signal-to-noise ratio for 1–10 photons/pulse. Compared with existing studies, the proposed system demonstrates enhanced overall performance across various communication metrics. Full article

A homogeneous photocatalyst on a stable substrate is required for photocatalytic reactors in wastewater treatment. ZnO films were synthesized on stainless steel prepared by the spray pyrolysis technique at different deposition temperatures (350 to 500 °C in steps of 50 °C). Scanning electron microscopy showed microflowers formed by nanopetals with an average size of 2 μm. The ZnO wurtzite structure and its defects were studied by Raman spectroscopy, X-ray diffraction, diffuse reflectance, and photoluminescence spectroscopy. A deposition temperature of 400 °C was chosen due to the presence of a higher number of vibrational modes, better distribution of microflowers, smaller crystallite size and a higher number of defects than the other options. Lanthanides were incorporated into ZnO by solution spraying, and then thermal treatment was performed at 600 °C. The photocatalytic evaluation of ZnO showed the best photocatalytic activity under UV light at 365 nm with a 69.34% degradation efficiency at 120 min. Photocatalytic activity toward methylene blue degradation was enhanced in ZnO:Ce³⁺ (2 and 4 atom%) and ZnO:Nd³⁺ (0.05 and 2 atom%) samples, achieving degradation efficiencies above 90% within 30 min of UV–visible light irradiation. Full article

Using bismuth oxide (Bi₂O₃) as the matrix and employing a doping modification strategy to introduce the rare-earth element La, this study prepared La/Bi₂O₃ visible-light-responsive photocatalysts with different doping ratios. The research systematically investigated the regulation mechanisms of La doping on the material’s phase structure, microstructure, band structure characteristics, and visible-light photocatalytic performance. The results indicate that an appropriate amount of La³⁺ equivalently substitutes Bi³⁺ in the lattice, inducing the complete transformation of pure α-Bi₂O₃ into the tetragonal β-Bi₂O₃ phase while maintaining the integrity of the crystal framework. Meanwhile, the modulation of the local electronic structure caused by La³⁺ substitution effectively narrows the bandgap width and broadens the visible-light response range; it also acts as an electron trap to significantly suppress the recombination of photo-generated electron–hole pairs, thereby enhancing charge transport efficiency. Visible-light catalytic degradation experiments confirmed that 4% La/Bi₂O₃ exhibits the optimal degradation kinetics for RhB, achieving a 72.88% degradation rate of Rhodamine B within 60 min of visible-light irradiation. The first-order reaction rate constant was 23 times that of pure Bi₂O₃, and the material demonstrated good stability under repeated cycles. Radical trapping experiments indicated that the order of contribution of active species was ·O₂⁻ > h⁺ > ·OH, with the superoxide radical (·O₂⁻) being the dominant active species. This study confirms that appropriate lattice doping with La can synergistically optimize the structure and optoelectronic properties of Bi₂O₃, providing experimental evidence and theoretical references for the rational design of highly efficient and stable visible-light-responsive Bi₂O₃-based photocatalytic materials. Full article

Photodynamic therapy (PDT) is a reactive oxygen species (ROS)-based treatment modality whose efficacy is often limited by poor photosensitizer stability and delivery. In this study, mesoporous silica-coated iron oxide nanoclusters (MNCs) were synthesized and loaded with protoporphyrin IX (PPIX) to obtain a multifunctional PPIX@MNC nanoplatform. Physicochemical characterization was performed using transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential analysis, and Fourier-transform infrared spectroscopy (FTIR). The biological effects of MNC, free PPIX, and PPIX@MNC were evaluated in HaCaT cells—as a general epithelial model—under dark conditions, light irradiation, cold atmospheric plasma (CAP) exposure, and combined CAP-assisted photodynamic treatment. FTIR, DLS, and zeta potential analyses confirmed successful incorporation of PPIX into the nanoclusters. Cell viability assays revealed pronounced phototoxicity of free PPIX, with the IC50 value decreasing from 44.4 ± 3.5 nM under dark conditions to 14 ± 2 nM following light activation, corresponding to a phototoxicity index of 3.17. CAP further enhanced PPIX-mediated cytotoxicity, and the CAP-assisted photodynamic group exhibited the strongest response, with an IC50 value of 9.6 ± 1.1 nM. CAP further enhanced PPIX-mediated cytotoxicity. Increased ROS generation, enhanced apoptosis, and marked mitochondrial membrane potential disruption were observed particularly in CAP-Light-PPIX-treated cells. Although encapsulation of PPIX within MNCs reduced acute cytotoxicity compared with free PPIX, the nanoplatform retained responsiveness to light and CAP stimulation. These findings demonstrate that CAP potentiates PPIX-mediated photodynamic effects through enhanced oxidative stress and suggest that mesoporous silica-coated magnetic nanoclusters represent a promising platform for controlled photosensitizer delivery in CAP-assisted PDT applications. Full article

Background/Objectives: This study aimed to investigate the effect of UVC irradiation on the adhesive strength between a CAD/CAM composite resin block and dentin and to apply UVC to dental care. Methods: CAD/CAM composite resin blocks were sectioned, polished, and primed using a ceramic primer. Bovine dentin specimens were prepared and irradiated with 222 nm UVC light for no time (control, no UV), 600 s or 1200 s. After irradiation, dentin surfaces were conditioned with a tooth primer before bonding with a resin cement. Microtensile bond strength (μTBS) testing, scanning electron microscope (SEM)-based failure mode analysis, and contact angle measurements were conducted. Results: The control measured 34.32 (±3.11) MPa, the 600 s group measured 42.64 (±4.50) MPa, and the 1200 s group measured 39.75 (±7.52) MPa. There were no significant differences observed in the 1200 s group when compared with the control group. Conversely, a remarkable increase in adhesive strength was observed in the 600 s group in comparison to the control group. Failure mode analysis revealed a predominance of mixed failures in the 600 s group, which suggests enhanced interfacial bonding. Contact angle measurements demonstrated significantly enhanced surface wettability in both UVC irradiation groups relative to the control (p < 0.05). Conclusions: Photofunctionalization with 222 nm UVC improved dentin adhesion to CAD/CAM resin blocks, likely through enhanced hydrophilicity and removal of organic contaminants. Nonetheless, extended irradiation did not produce additional benefits, indicating a time-dependent response. Although 222 nm UVC irradiation demonstrates promise as a pretreatment approach in adhesive dentistry, further optimization is necessary to shorten irradiation duration and improve clinical feasibility. Full article

Organic pollutants in industrial wastewater present a severe threat to both the environment and human health. Photocatalytic technology, recognized for its eco-friendliness and high efficiency, has become a leading approach for degrading such pollutants. In this work, BiOCl nanosheets were first synthesized using a hydrothermal method. Subsequently, an anion exchange reaction with TAA in an oil bath generated a Bi₂S₃ intermediate layer on the BiOCl surface, followed by the in situ growth of ZIS nanostructures, successfully constructing a BiOCl@Bi₂S₃@ZIS double Z-scheme heterojunction. By adjusting the amount of BiOCl, the interface contact and dispersion of the heterojunction were optimized. Characterization results demonstrate that the BiOCl@ZIS-25 heterojunction possesses the highest specific surface area (103.5 m²·g⁻¹) and the most efficient charge separation. Under visible light irradiation, it achieved 97.88% degradation of methylene blue within 20 min, with a reaction rate constant 8 and 4 times higher than those of pure BiOCl and ZIS, respectively. Mechanistic investigations indicate that Bi₂S₃ interlayer acts as an electron-transfer bridge between BiOCl and ZIS, establishing a double Z-scheme charge transfer pathway that significantly enhanced the separation and utilization efficiency of photogenerated charge carriers. This study offers valuable insights for designing highly efficient and stable photocatalytic composite materials. Full article

A light-promoted C–H/C–H coupling of imidazo[1,2-a]pyridines with 5-(hetero)aryl-1,2,5-oxadiazolo[3,4-b]pyrazines was developed using a heterogeneous oxidative photocatalytic system based on molecular oxygen, nanosized TiO₂, and light irradiation. The method provides direct access to C3-heteroarylated imidazo[1,2-a]pyridines under metal-free conditions and expands the synthetic utility of electron-deficient oxadiazolopyrazine partners in the construction of biheteroaryl scaffolds. The synthesized compounds were evaluated computationally using a fully connected convolutional correlation neural network based on multiple-docking energy spectra, which prioritized the series as potential COX-1 and COX-2 ligands. To test this prioritization experimentally, all 18 compounds were screened in fluorometric COX-1 and COX-2 inhibitor assays at 1 µM. Compound 3f emerged as a strong preliminary COX-1 hit at 1 µM (86.64 ± 5.18% inhibition), whereas 3h and 3l showed weaker COX-1 inhibition. No compound showed high or moderate COX-2 inhibition at the screening concentration; only weak COX-2 inhibitory signals were observed for several derivatives. Thus, the combined synthetic, computational, and enzymatic data identify compound 3f as the main COX-1-skewed hit in this series and provide a basis for further dose–response, selectivity, and cell-based anti-inflammatory studies. It should also be noted that the COX-1 inhibition assay used ovine COX-1, whereas the computational models were built on human COX-1 and COX-2 structures; this species difference is an additional reason to treat the in silico–experimental comparison as approximate. Full article

Photocatalytic antibacterial coatings have emerged as a promising antibiotic-free strategy for combating healthcare-associated infections, biofilm formation, marine biofouling, and environmental microbial contamination. Unlike conventional antimicrobial approaches, photocatalytic systems continuously generate reactive oxygen species (ROS) under light irradiation, enabling broad-spectrum antimicrobial activity while minimizing the risk of antimicrobial resistance. This review systematically summarizes the fundamental mechanisms underlying photocatalytic antibacterial activity, including photogenerated charge-carrier dynamics, ROS generation pathways, and microbial inactivation processes. We further highlight recent advances in photocatalyst design, spanning conventional semiconductor photocatalysts, heterojunction engineering, cocatalyst modification, and two-dimensional material-assisted strategies for enhanced photocatalytic performance. Crucially, particular emphasis is placed on coating architectures and interfacial regulation, including encompassing fabrication methodologies, coating–substrate adhesion, internal heterointerface design, and coating–microorganism interactions, which dictate long-term durability and antibacterial efficacy. Finally, we explore the diverse applications of these coatings in medical devices, environmental remediation, and marine antifouling, while identifying current bottlenecks and future research trajectories toward developing durable, highly efficient, and clinically translatable antimicrobial surface technologies. Full article

The photocatalytic degradation of Acid Orange 7 (AO7) in aqueous solution in the presence of exfoliated C₃N₄ (n-C₃N₄) as a photocatalyst was investigated under simulated solar light irradiation. The n-C₃N₄ photocatalyst was synthesized by polymerization of urea as a precursor and characterized by UV/Vis and FTIR spectroscopy, and transmission electron microscopy. Degradation products were identified by high-performance liquid chromatography with high-resolution mass spectrometry (LC–HRMS). It was found that AO7 undergoes a series of oxidation steps mediated by radicals generated during light absorption by n-C₃N₄, as well as through a photosensitization process initiated by light absorption by AO7. This results in decolorization and the formation of aromatic and aliphatic intermediates, which undergo further oxidation to simpler compounds. Full article