Search Results (2,502)

Blue-light stimulation of the optic disc has been suggested as a means of myopia prevention by activating dopaminergic amacrine cells via intrinsically photosensitive retinal ganglion cells. This prospective, adequately powered study investigated this approach by examining its effects on pattern electroretinogram (PERG) N95 amplitude and choroidal thickness (ChT), established biomarkers associated with retinal ganglion cell function and myopia progression, respectively. Forty-six healthy adults received one minute of 450 nm blue-light stimulation to either the optic disc or central retina of the right eye, with the fellow left eye serving as control. PERG responses were measured before and 20 min after stimulation (N = 15 per stimulation location), while ChT, using swept-source optical coherence tomography images, was measured before, 20, and 60 min after stimulation (N = 8 per stimulation location). Only retinal stimulation significantly increased PERG N95 amplitude (baseline 16.16 µV, post-stimulation 17.61 µV [p = 0.01]), whereas optic disc stimulation did not (baseline 18.71 µV, post-stimulation 18.81 µV [p = 0.76]). Neither optic disc nor retinal stimulation significantly changed ChT at any time point. No significant differences were observed between myopic and non-myopic participants. Our findings do not support the hypothesis that short-duration blue-light stimulation of the optic disc is a viable strategy to activate retinal dopaminergic pathways for myopia prevention. Full article

Localized therapeutic action and targeted drug release offer compelling advantages over traditional systemic drug administration. This is particularly important for nitric oxide (NO), whose biological effects vary greatly depending on concentration and cellular environment. Light-sensitive NO donors are promising for achieving precise, on-demand NO release. However, their efficiency and photostability are limited by competing photophysical processes and the generation of reactive oxygen species (ROS). In this study, we investigate hybrid systems composed of photosensitive nitric oxide (NO) donors and silver island films (SIFs). The influence of localized surface plasmon on non-radiative relaxation pathways and ROS generation is the main focus of the paper. Upon excitation at 500 nm, we observed several-fold increase in NO release, attributed to resonant interactions between the plasmonic field and the dye molecules. By tuning the thickness of a SiO₂ buffer layer, we identified key parameters affecting process efficiency: the spectral overlap between the plasmon resonance and the sensitizer’s absorption band, and the distance between the nanoparticle and the molecule. Additionally, singlet oxygen generation increase was observed. These findings demonstrate the potential of plasmonic enhancement to controllably boost photochemical activity in organic systems, paving the way for advanced applications in phototherapy and biomedical diagnostics. Full article

Cholangiocarcinoma is a rare, highly aggressive malignancy of the hepatobiliary tract with poor prognosis, often diagnosed at advanced stages when curative surgical resection is not feasible. Management increasingly relies on advanced endoscopic interventions to address malignant biliary obstruction and improve clinical outcomes. Beyond conventional biliary stenting, adjunctive endoscopic ablation therapies have emerged as promising strategies to improve both stent patency and survival. This review comprehensively examines the evolving role of radiofrequency ablation and photodynamic therapy in the treatment of unresectable cholangiocarcinoma. Radiofrequency ablation utilizes localized thermal energy to induce coagulative tumor necrosis and offers advantages including procedural simplicity, favorable safety profile, and cost-effectiveness; however, its efficacy may be limited by tumor size, location, and proximity to critical structures. In contrast, photodynamic therapy employs light-activated photosensitizers to selectively induce cytotoxicity in malignant tissue, demonstrating superior outcomes in prolonging both stent patency and overall survival across multiple studies and meta-analyses. Photodynamic therapy’s ability to treat more diffuse and peripheral lesions represents an important advantage, though its use is limited by photosensitivity reactions and shallow tissue penetration. Ultimately, endoscopic ablation therapies represent valuable adjunctive options in the multidisciplinary care of patients with unresectable cholangiocarcinoma. As technological advances continue and more comparative data emerge, optimized patient selection and individualized integration of these therapies hold potential to significantly improve outcomes in this challenging malignancy. Full article

Despite aggressive current therapies against glioblastoma (GB), residual tumor cells may remain at the edge of the surgical cavity after resection. These cells can rapidly proliferate, giving rise to tumor recurrence in more aggressive and drug-resistant forms. As photodynamic therapy (PDT) has advanced, it has emerged as an option to treat this brain tumor. The oncological basis of PDT involves the selective accumulation of a photosensitizer (PS) in the tumor, followed by its activation with electromagnetic radiation to generate reactive oxygen species (ROS), which induce tumor cell death. Given that first- and second-generation PSs present significant limitations, including poor tumor selectivity, suboptimal biodistribution, limited absorption within the therapeutic window, and slow systemic clearance, research has progressed toward the development of third-generation PSs based on nanotechnology to optimize their therapeutic properties. This review addresses the types of tumor cell death induced by PDT, as well as the advancements of PS design, focusing on titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles. These nanomaterials can be designed as carriers, encapsulating or conjugating conventional PSs, or act as PSs themselves, due to their favorable biocompatibility and intrinsic photoreactivity. Additionally, they can be functionalized with targeting ligands to achieve tumor-specific delivery, enhancing therapeutic selectivity while minimizing toxicity to healthy tissue. Overall, these nanotechnology-based PSs represent a versatile and promising therapeutic paradigm that warrants further investigation through basic research, supporting the development and potential clinical translation of a more precise and effective PDT-based intervention for glioblastoma, initially aimed at eliminating intra-surgical post-resection residual tumor cells. Full article

Background: Vandetanib is a clinically approved epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) used in the treatment of medullary thyroid cancer. Recent studies have also suggested potential activity against the SARS-CoV-2 main protease (Mpro), indicating dual therapeutic relevance. However, its clinical use is limited by photosensitivity side effects, the molecular basis of which remains poorly understood. This study aims to elucidate the conformational, spectroscopic, and electronic properties of vandetanib underlying its photoreactivity. Methods: Density functional theory (DFT) was employed to explore vandetanib’s conformational landscape, electronic structure, and spectroscopic behavior. Low-energy conformers were identified and compared with experimental crystal and NMR data. Time-dependent DFT (TD-DFT) calculations were used to simulate UV–Vis absorption spectra and assign key electronic transitions. Results: Eight low-energy conformer clusters, including the global minimum structure, were identified. The global minimum was validated by consistency with crystal and experimental NMR data, emphasizing the role of conformational averaging. TD-DFT simulations successfully reproduced the two main UV–Vis absorption bands, with the primary band (~339 nm) assigned to a HOMO–1 → LUMO charge-transfer excitation between the N-methyl piperidine and quinazoline rings, pinpointing a structural contributor to photoreactivity. Additionally, the N-methyl piperidine ring was identified as a major metabolic hotspot, undergoing multiple biotransformations potentially linked to phototoxicity. Conclusions: This study provides molecular-level insights into the structural and photophysical origins of vandetanib’s photosensitivity. The findings improve understanding of its adverse effects and can inform the safer design of EGFR-targeting drugs with reduced phototoxic risks. Full article

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, limiting the efficacy of conventional targeted therapies. As a result, novel therapeutic strategies are urgently needed. Photodynamic therapy (PDT), which relies on the activation of photosensitizers (PSs) by light to induce cytotoxic effects, has emerged as a promising alternative for TNBC treatment. Furthermore, the conjugation of PSs with targeting peptides has demonstrated enhanced selectivity and therapeutic efficacy, particularly for porphyrin-based photosensitizers. In this study, we report the synthesis of novel porphyrin–peptide conjugates designed to selectively target the epidermal growth factor receptor (EGFR), which is frequently overexpressed in TNBC. The conjugates were prepared via thiol displacement of the meso-nitro group in a 5,15-diarylporphyrin scaffold using EGFR-binding peptides. Photodynamic activity was evaluated in two EGFR-overexpressing TNBC cell lines. Cellular uptake of the conjugates correlated with EGFR expression levels, and PDT treatment resulted in differential induction of necrosis, apoptosis, and autophagy. Notably, the conjugates significantly inhibited EGFR-expressing cell line migration, a critical hallmark of metastatic progression. These findings underscore the potential of EGFR-targeted porphyrin–peptide conjugates as promising PDT agents for the treatment of TNBC. Full article

Background/Objectives: Hydroxychloroquine (HCQ) is frequently used to manage cutaneous manifestations associated with idiopathic inflammatory myopathies (IIMs). Nevertheless, the literature lacks consensus regarding the efficacy and safety of drugs for these manifestations. Methods: A systematic literature review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. The search spanned the period from January 1958 to April 2025 across the following databases: PubMed, Scopus, Web of Science, Cochrane Library, PsycInfo, and Virtual Health Library. Articles were included if they contained at least one of the specified descriptors in the title or abstract; were published in English, Portuguese, or Spanish; and addressed the use of HCQ or chloroquine (CQ) in the context of skin manifestations of IIMs. Review articles, experimental studies, and short communication articles were excluded. Results: Among the 319 patients assessed, the majority were women diagnosed with dermatomyositis or juvenile dermatomyositis. The most prevalent cutaneous manifestations were Gottron’s papules and diffuse erythematous lesions. The most frequent extracutaneous manifestations were muscle weakness and arthritis/arthralgia. HCQ was administered in 74% of the cases, with dosages ranging from 200 to 400 mg/day and a follow-up duration of 26 months. In most cases, it is administered in conjunction with glucocorticoids. Adverse effects were observed in less than 9% of the patients, with myalgia, skin lesions, and photosensitivity being the most common. However, the use of CQ has not been documented in any of these studies. Conclusions: Although there are studies in the literature using HCQ as part of the treatment of cutaneous manifestations in patients with IIMs, longitudinal studies with larger sample sizes and more robust methods are required to evaluate the applicability of HCQ in the treatment of IIMs. Full article

Singlet oxygen (¹O₂), a reactive oxygen species, can oxidize lipids, proteins, and DNA at high concentrations, leading to cell death. Despite its extremely short half-life (10⁻⁵ s), ¹O₂ acts as a critical signaling molecule, triggering a retrograde pathway from chloroplasts to the nucleus to regulate nuclear gene expression. In this study, rice seeds were treated with 0, 5, 20 and 80 μM Rose Bengal (RB, a photosensitizer) under moderate light for 3 days to induce ¹O₂ generation. Treatment with 20 μM RB reduced stomatal density by approximately 25% in three-leaf-stage rice seedlings, while increasing the contents of pectin, hemicellulose, and cellulose in root cell walls by 30–40%. Under drought, salinity, or shading stress, 20 μM RB treatment significantly improved rice tolerance, as evidenced by higher relative water contents (49–58%) and chlorophyll contents (60–76%) and lower malondialdehyde (37–43%) and electrolyte leakage (29–37%) compared to the control. Moreover, RT-qPCR analysis revealed that the significant up-regulation of stomatal development genes (OsTMM and OsβCA1) and cell wall biosynthesis genes (OsF8H and OsLRX2) was associated with RB-induced ¹O₂ production. Thus, under controlled environmental conditions, ¹O₂ may regulate stomatal development and cell wall remodeling to enhance rice tolerance to multiple abiotic stresses. These results provide new perspectives for the improvement of rice stress tolerance. Full article

Ceramide 1-phosphate (C1P) is a key regulator of cell proliferation and survival in both normal and transformed cells. Major pathways implicated in the mitogenic actions of C1P include activation of the mitogen-activated protein kinases (MAPKs) ERK1-2 and JNK, as well as stimulation of the phosphatidylinositol 3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, the product of retinoblastoma, or the sphingomyelin synthase (SMS)/diacylglycerol (DAG)/protein kinase C-alpha (PKC-α) pathway. C1P-stimulated cell proliferation can also be mediated through enhanced secretion of vascular endothelial growth factor (VEGF) in macrophages or by releasing lysophosphatidic acid (LPA) in myoblasts. Also, the production of low levels of reactive oxygen species (ROS) can mediate the stimulation of cell growth by C1P, particularly in macrophages. Upregulation of the PI3K/Akt/mTOR pathway is also involved in the inhibition of cell death by C1P, which can also contribute to cell survival by blocking the activity of the ceramide-generating enzymes acid sphingomyelinase (ASMase) and serine palmitoyl transferase (SPT). Moreover, C1P-promoted cell survival involves upregulation of inducible nitric oxide synthase (iNOS) and the subsequent production of nitric oxide (NO). Using photosensitive C1P analogues, it could be concluded that promotion of cell growth and inhibition of cell death were elicited by intracellularly generated C1P in a receptor-independent manner. The aim of the present review is to evaluate in detail the implication of the CerK/C1P axis in controlling cell proliferation and survival in mammalian cells, as well as to discuss and update on the molecular mechanisms by which C1P can accomplish these actions. Full article

Photopolymer PQ/PMMA, as a pivotal material in the field of holographic storage, demonstrates significant application potential owing to its advantages, such as straightforward preparation processes, cost-effectiveness, and tunable thickness. However, its practical application is still constrained by the need for further enhancement in key performance indicators, including diffraction efficiency, photosensitivity, and anti-aging properties. In this study, N-vinylpyrrolidone (NVP) is employed as a comonomer. By precisely controlling the doping ratio, we systematically investigate the influence mechanism of different NVP doping concentrations on the holographic performance of NVP-PQ/PMMA materials. Research indicates that the introduction of NVP effectively increases the vinyl concentration in the PQ/PMMA matrix, thereby directly generating photoproducts with PQ during the photoreaction process and further enhancing the photopolymerization process. Consequently, the holographic performance of the novel NVP-PQ/PMMA material is improved in a multi-faceted manner compared to ordinary PQ/PMMA. Specifically, the diffraction efficiency is enhanced by 1.93 times, the photosensitivity is increased by 1.64 times, the material uniformity is improved by 38%, and the light-induced shrinkage rate is reduced by 39%. Additionally, NVP-PQ/PMMA materials exhibit excellent stability and aging resistance in high-temperature accelerated aging experiments. Doping with a monomer of specific structure enhances the optical properties, providing broad adaptability for further research on PQ/PMMA photopolymer materials. Full article

Perylenequinonoid compounds, represented by photosensitive therapeutic agents such as hypocrellins and elsinochromes, demonstrate extensive potential across biomedical, agricultural, and food industrial applications. Nevertheless, their restricted biosynthesis remains a critical bottleneck for commercial exploitation. This study implemented UV mutagenesis to enhance perylenequinone production in fungal strains of Pseudoshiraia conidialis, achieving significant yield improvements at the 120 J/m² and 150 J/m² irradiation intensities. Through systematic optimization of the HPLC analytical platform, we established the precise quantification of five distinct perylenequinonoid derivatives: hypocrellin A, hypocrellin B, shiraiachrome A, elsinochrome A, and elsinochrome B. The mutant strain Z2-1 demonstrated a remarkable biosynthetic capacity with the total perylenequinonoid yields reaching 2101.6 mg/L, representing a 705.70% enhancement over the parental strain zzz816 (260.84 mg/L). Particularly noteworthy was the hyperproduction of hypocrellin A at 1100.7 mg/L, corresponding to a 1208.02% increase from the baseline yield (84.15 mg/L). Furthermore, this work reports the first successful generation of an elsinochrome A-overproducing strain, achieving a 312.68 mg/L output (429.25% increase from 59.08 mg/L). Intriguingly, different mutant strains exhibited distinct production profiles for specific compounds, revealing biosynthetic preference variations among derivatives. These findings emphasize the necessity for comprehensive metabolite profiling during fermentation process optimization to maximize the target compound yields. Full article

Based on the photoconductive effect of photosensitive films, a designed light pattern was projected onto a hydrogenated amorphous silicon (a-Si:H) photosensitive chip to generate virtual light-induced electrodes for cellular electrical detection. To obtain high-quality cellular signals, this study aims to explore the effect of electrical excitation on a-Si:H photosensitive chip. Firstly, the electrochemical impedance spectroscopy (EIS) and volt-ampere characteristics of the a-Si:H photosensitive chip were characterized. EIS data were fitted to extract equivalent circuit models (ECMs) for both the chip and system. Then analog experiments were performed to verify the ECMs, and the results were consistent with the circuit simulation. Finally, applied alternating current (AC) or direct current (DC) signals to the chip and recorded the electrical signals of the cultured cardiomyocytes on the a-Si:H photosensitive chip. The results demonstrated that applying a high-frequency small AC signal to the chip reduced the background noise of the system by approximately 85.1%, and applying a DC bias increased the amplitude of the detection signal by approximately 142.7%. Consequently, the detection performance of the a-Si:H photosensitive chip for weak bioelectrical signals was significantly enhanced, advancing its applicability in cellular electrophysiological studies. Full article

Background/Objectives: Patients with erythropoietic protoporphyria (EPP) have a decreased activity of the ferrochelatase enzyme which converts protoporphyrin IX (PpIX) into heme, causing PpIX to accumulate in erythrocytes. The ensuing release of PpIX to the skin when exposed to visible light causes a phototoxic reaction with severe pain, erythema, and edema. Erythrocyte PpIX levels in adult EPP patients are rather stable and largely unaffected by pharmaceutical treatments. It is important to be aware of drugs causing an increase in PpIX as this may increase the risk of liver toxicity. Method: The patient had blood samples taken regularly for analyses of PpIX, znPpIX, ALT, ALP, iron, leucocytes, C-reactive protein, and hemoglobin before, during, and after treatment with teriflunomide. Additionally, we tested if teriflunomide increased PpIX in vitro. Results: A female EPP patient was treated for 7 years with teriflunomide for multiple sclerosis attacks. During treatment, her natural PpIX level increased from about 30 µmol/L to about 200 µmol/L, without significant simultaneous changes in hemoglobin, iron levels, alanine transaminase (ALT), or alkaline phosphatase (ALP). The patient experienced no increase in photosensitivity. In vitro addition of teriflunomide did not affect PpIX levels. Discussion: In patients with lead intoxication, the release of PpIX from erythrocytes is very slow. The increase in PpIX during treatment with teriflunomide compared to periods with no medication could be caused by a similar slow PpIX release from the erythrocytes. This theory is supported by the patient’s unchanged light sensitivity and stable levels of hemoglobin, iron, and liver enzymes. Full article

Aqueous singlet oxygen (¹O₂) sensitization is of high interest due to its wide application in bio-imaging and photodynamic therapy. For organic photosensitizers like porphyrin derivatives, surfactant-assisted micelles have been intensively explored for dispersing hydrophobic sensitizers in aqueous phase; however, they can suffer from poor long-term stability. In this work, palladium octaethylporphyrin (PdOEP)-embedded silica particles were prepared with assistance from Tween micelles, and their corresponding application in aqueous ¹O₂ sensitization was explored. With assistance from Tween 80 at a >3 mg/mL concentration, superior (>95%) solubilization of PdOEP was observed in aqueous solution, leading to a high ¹O₂ quantum yield (Φ_Δ ≈ 93%). By optimizing the synthesis conditions, >95% of micellar PdOEP was embedded into silica particles, exhibiting comparable Φ_Δ (up to 70%) to micellar systems by effectively suppressing PdOEP aggregation in particles. The PdOEP-embedded silica particles exhibited dramatically enhanced long-term stability (more than one year) compared to corresponding micelles with a half-life of ~38 days. In addition, aqueous ¹O₂ sensitization by PdOEP-embedded silica particles was demonstrated upon two-photon excitation in a near-infrared regime (λ_ex = 1030 nm), highlighting the great potential of this method for future biological applications. Full article

Bacterial infections cause serious problems associated with wound treatment and serious complications, leading to serious threats to the global public. Bacterial resistance was mainly attributed to the formation of biofilms and their protective properties. Hydrogels suitable for irregular surfaces with effective antibacterial activity have attracted extensive attention as potential materials. In this study, a succinoglycan-riclin-zinc-phthalocyanine-based composite (RL-Zc) hydrogel was synthesized through an amine reaction within an hour. The hydrogel was characterized via FT-IR, SEM, and rheology analysis, exhibiting an elastic solid gel state stably. The hydrogel showed large inhibition circles on E. coli as well as S. aureus under near-infrared irradiation (NIR). RL-Zc hydrogel exhibited positively charged surfaces and possessed a superior penetrability toward bacterial biofilm. Furthermore, RL-Zc hydrogel generated abundant single oxygen and mild heat rapidly, resulting in disrupted bacterial biofilm as well as amplified antibacterial effectiveness. A metabolomics analysis confirmed that RL-Zc hydrogel induced a metabolic disorder in bacteria, which resulted from phospholipid metabolism and oxidative stress metabolism related to biofilm disruption. Hence, this study provided a potential phototherapy for biofilm-induced bacterial resistance. Full article