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BackgroundPhotodynamic therapy (PDT) efficacy is determined in part by the concentration of photosensitizer (PS) at the treatment site. The blood-brain barrier (BBB) poses a significant limitation on the transport of PS into the post-operative resection region where brain tumors most often recur. Macrophages (Ma), as opposed to free or nanoparticle bound agents, are known to actively migrate to and around tumors, and can therefore be used as delivery vectors for both drugs and photosensitizers.MethodsMouse Ma (RAW264.7) and F98 rat glioma cells were used in all experiments along with the photosensitizer AlPcS2a. Mitomycin-treated Ma were loaded with photosensitizer (PS) and mixed with glioma cells, forming hybrid spheroids. F98 spheroids were incubated with supernatants derived from PS-loaded Ma (MaPS). Light treatment (PDT) was administered at various radiant exposures from a 670 nm diode laser. The growth of both types of spheroids was evaluated by measurement of spheroid volume after 14 days in culture.ResultsPDT on F98 cell spheroid cultures, mediated by either free or PS-released from Ma, demonstrated a significant growth inhibition with supernatants harvested after 4 and 24 h. A significant PDT-induced growth inhibition was demonstrated in the MaPS/F98 hybrid spheroid experiments.ConclusionSince the efficacy of PDT, mediated by either free or released photosensitizer was comparable, the uptake and released photosensitizer was not degraded. MaPS, incorporated in hybrid tumor spheroids also mediated effective PDT. These results indicate that Ma have potential as an effective vector for photosensitizer delivery to resected brain tumors.

An asymmetric zinc phthalocyanine dye (ZnPcT3C), bearing three tetraethylene glycol donor groups and one carboxylic acid anchoring group, was synthesized as a photosensitizer dye for dye‐sensitized solar cells (DSSCs). The tetraethylene glycol (TEG), consisting of four ethoxy units, works as an amphiphilic long‐chain donor group that greatly helped in reducing the molecular aggregation. Carboxylic acid group, on the other hand, an acceptor, together with TEG in ZnPcT3C functions as a 'push–pullʼ system suitable for DSSCs. Absorption spectra of ZnPcT3C in DMSO showed a strong sharp Q band in the infrared region 600–700 nm with (λmax = 682 nm) and a less intense soret band appeared in the region 300–400 nm with λmax = 340 nm. The zinc phthalocyanine (ZnPcT3C) exhibited molar extinction coefficient (ε) of 72,727 L mol−1cm−1. The emission was observed at λem = 695 nm upon excitation at 650 nm and exhibited a fluorescence decay of 2.82 ns. The ZnPcT3C dye sensitised solar cell (c = 1 mM) exhibited the power conversion efficiency (η) of 3.52% in chloroform in I−/I3 electrolyte under simulated 100% brightness. Cosensitization of ZnPcT3C with another auxiliary dye D131 in 1:1 ratio in a cocktail‐type DSSC attained the power conversion efficiency of twice as high as η = 6.27% in an identical condition. A mixture of D131 (λmax = 470 nm) dye with the ZnPcT3C phthalocyanine harvests sunlight across the visible spectra, enabling DSSCs to attain a large photocurrent and photovoltage, enhancing power conversion efficiency. [ABSTRACT FROM AUTHOR]

ABSTRACT The photosensitizer mechanism by the psoralen (PSO) reacts to produce reactive oxygen species has not been thoroughly studied; thus, this work was carried out a study of the reaction and mechanism involved in the photosensitizer activity of PSO, employing M06‐2X/6‐311++G(d,p) of the density functional theory. There is a competition between the generation of radical anion superoxide (type I mechanism) and the singlet oxygen molecule (type II mechanism) in lipid media; therefore, the ROS anion superoxide and singlet oxygen could be formed as products of the reaction involved in the photosensitizer activity of PSO in lipid media. In aqueous media, the reaction involved in the photosensitizer activity of PSO was only attributed to the type I mechanism; hence, in aqueous media, the photosensitizer activity of PSO yielded the anion superoxide. The present study supports the photosensitizer activity of the PSO in lipid and aqueous media. It enhances the knowledge of these reactions in different media and their application to reactivity, including the physiology media. [ABSTRACT FROM AUTHOR]

Background: Near-infrared photoimmunotherapy (NIR-PIT) is an emerging cancer treatment technology that combines the advantages of optical technology and immunotherapy to provide a highly effective, precise, and low side-effect treatment approach. The aim of this study is to visualize the scientific results and research trends of NIR-PIT based on bibliometric analysis methods. Methods: The Web of Science Core Collection (WoSCC) database was searched in August 2024 for relevant publications in the field of NIR-PIT. Data were analyzed using mainly CiteSpace and R software for bibliometric and visual analysis of the country/region, authors, journals, references and keywords of the publications in the field. Results: A total of 245 publications were retrieved, including articles (n = 173, 70.61%) and reviews (n = 72, 29.39%). The annual and cumulative number of publications increased every year. The highest number of publications was from the United States (149, 60.82%), followed by Japan (70, 28.57%) and China (33, 13.47%). The research institution with the highest number of publications was National Institutes of Health (NIH)-USA (114, 46.53%). Kobayashi H (109) was involved in the highest number of publications, Mitsunaga M (211) was the most frequently cited in total. CANCERS (17) was the most frequently published journal, and NAT MED (220) was the most frequently co-cited journal. The top 10 keywords include near-infrared photoimmunotherapy (166), photodynamic therapy (61), monoclonal antibody (58), in vivo (50), cancer (46), expression (31), breast cancer (27), enhanced permeability (24), antibody (23), growth factor receptor (16). Cluster analysis based on the co-occurrence of keywords resulted in 13 clusters, which identified the current research hotspots and future trends of NIR-PIT in cancer treatment. Conclusion: This study systematically investigated the research hotspots and development trends of NIR-PIT in cancer treatment through bibliometric and visual analysis. As an emerging strategy, the research on the application of NIR-PIT in cancer treatment has significantly increased in recent years, mainly focusing on the targeting, immune activation mechanism, and treatment efficacy in solid tumors has received extensive attention. Future studies may focus on improving the efficacy and safety of NIR-PIT in cancer treatment, as well as developing novel photosensitizers and combination therapeutic regimens, and exploring the efficacy of its application in a wide range of solid tumors, which will provide an important reference and guidance for the application of NIR-PIT in clinical translation. [ABSTRACT FROM AUTHOR]

The field of biofabrication imposes stringent requirements on the polymerization activity and biosafety of photopolymeric hydrogel systems. In this investigation, we designed and synthesized four hemicyanine dyes with a D‐π‐A structure specifically tailored for biofabrication purposes. These novel dyes, incorporating carbazole (CZ), triphenylamine (TPA), anthracene (AN), and benzodithiophene (BDT) as electron donors, along with heterocyclic salt (IN) as electron acceptors, were prepared using a straightforward synthesis method. The absorption maxima of ANIN, CZIN, and TPAIN exceeded 500 nm, rendering them suitable co‐initiators for the free radical photopolymerization of acrylates under green‐red light exposure facilitated by light‐emitting diodes (LEDs) and the co‐initiator iodonium salt (ION). Notably, CZIN and TPAIN, due to their robust dye absorption and efficient electron transfer to ION, functioned as high‐performance photosensitizers. Meanwhile, BDTIN, with its strong and broad absorption range (400–600 nm), enhanced the accuracy of visible light photopolymerization. These dyes exhibit characteristics such as facile synthesis, heightened photo stability, and non‐toxicity and also demonstrate the ability to discern the alkalinity of a solution to some extent. Furthermore, we explored the application of these hemicyanine dyes in 3D printing, showing potential to enhance printing resolution in DLP 3D printing (digital light process 3D printing). [ABSTRACT FROM AUTHOR]

While surgical resection is a mainstay of cancer treatment, many tumors are unresectable due to stage, location, or comorbidities. Ablative therapies, which cause local destruction of tumors, are effective alternatives to surgical excision in several settings. Ethanol ablation is one such ablative treatment modality in which ethanol is directly injected into tumor nodules. Ethanol, however, tends to leak out of the tumor and into adjacent tissue structures, and its biodistribution is difficult to monitor in vivo. To address these challenges, this study presents a cutting‐edge technology known as Light‐Activatable Sustained‐Exposure Ethanol Injection Technology (LASEIT). LASEIT comprises a three‐part formulation: (1) ethanol, (2) benzoporphyrin derivative, which enables fluorescence‐based tracking of drug distribution and the potential application of photodynamic therapy, and (3) ethyl cellulose, which forms a gel upon injection into tissue to facilitate drug retention. In vitro drug release studies showed that ethyl cellulose slowed the rate of release in LASEIT by 7×. Injections in liver tissues demonstrated a 6× improvement in volume distribution when using LASEIT compared to controls. In vivo experiments in a mouse pancreatic cancer xenograft model showed LASEIT exhibited significantly stronger average radiant efficiency than controls and persisted in tumors for up to 7 days compared to controls, which only persisted for less than 24 h. In summary, this study introduced LASEIT as a novel technology that enabled real‐time fluorescence monitoring of drug distribution both ex vivo and in vivo. Further research exploring the efficacy of LASEIT is strongly warranted. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials, such as carbon quantum dots (CQDs), are excellent candidates for antibacterial agent development as they are cost-effective. Nitrogen-doped CQDs (N-doped CQDs) exhibit antibacterial activity against gram-positive bacteria. However, investigation of N-CQDs and their efficacy against the selected bacterial strains under visible light irradiation has not been carried out. Here, we aimed to evaluate N-CQDs for their efficacy as a photosensitizer for antimicrobial photodynamic therapy (aPDT). N-CQDs were synthesized using the hydrothermal method with 1,3,6-trinitropyrene (TNP) as the nitrogen and carbon source. Antimicrobial tests of N-CQDs were conducted against gram-positive (Bacillus subtilis NCIB 3610, Staphylococcus aureus Newman, and S. aureus USA300) and gram-negative (Escherichia coli K12) bacteria at different concentrations (0–100 mg/L). The N-CQDs exerted a moderate growth-inhibitory effect on gram-positive bacteria in the dark. However, in the presence of white light generated using 20-W light-emitting diode, N-CQDs could completely kill the bacteria at a low concentration of 20 mg/L. The minimal inhibitory concentration of N-CQDs for the two S. aureus strains (Newman and USA300) was 20 mg/L under light conditions, whereas that for B. subtilis was 100 mg/L. The results demonstrate that N-CQDs may be used as a photosensitizer in aPDT and as an antibacterial agent. [Display omitted] • Nitrogen-doped carbon quantum dots (N-CQDs) were produced by the hydrothermal method. • N-CQDs exerted moderate growth-inhibitory effect on gram-positive bacteria in dark. • Incubation with N-CQDs under the white light could completely kill the bacteria. • N-CQDs may be used as an antibacterial agent in antibacterial photodynamic therapy. [ABSTRACT FROM AUTHOR]

New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable. [ABSTRACT FROM AUTHOR]

To achieve artificial photosynthesis, it is crucial to develop a catalytic system for CO2 reduction using water as the electron source. However, photochemical CO2 reduction by homogeneous molecular catalysts has predominantly been conducted in organic solvents. This study investigates the impact of water content on catalytic activity in photochemical CO2 reduction in N,N-dimethylacetamide (DMA), using [Ru(bpy)3]2+ (bpy: 2,2′-bipyridine) as a photosensitizer, 1-benzyl-1,4-dihydronicotinamide (BNAH) as an electron donor, and two ruthenium diimine carbonyl complexes, [Ru(bpy)2(CO)2]2+ and trans(Cl)-[Ru(Ac-5Bpy-NHMe)(CO)2Cl2] (5Bpy: 5′-amino-2,2′-bipyridine-5-carboxylic acid), as catalysts. Increasing water content significantly decreased CO and formic acid production. The similar rates of decrease for both catalysts suggest that water primarily affects the formation efficiency of free one-electron-reduced [Ru(bpy)3]2+, rather than the intrinsic catalytic activity. The reduction in cage-escape efficiency with higher water content underscores the challenges in replacing organic solvents with water in photochemical CO2 reduction. [ABSTRACT FROM AUTHOR]

Literature proves that the direct detection of 1O2(1Δg) at the solid gas interface is systematically performed from its phosphorescence using high intensity excitation sources (i.e., lasers), which lead to quasi‐ubiquitous chemical problems, such as sensitizer degradation, and photophysical counter‐active issues such as ultrafast exciton migration, singlet‐singlet and triplet‐triplet annihilation, and thermally activated delayed fluorescence mediated by 1O2(1Δg). To avoid these inconveniences, low excitation intensity is required but leads to serious analytical challenges. The best practices to reliably detect 1O2(1Δg) phosphorescence at various interfaces using a standard excitation source and near‐IR detector. The two main practices consist in a gas purging test for reliable identification of 1O2(1Δg), and in a particularly fine optimization of the angle made by excitation beam versus substrate plane. These practices are applied to porphyrin sensitizers H2TPP and ZnTPP, either neat or physiosorbed on glass, quartz, paper and hospital bandages, graphene oxide (GO), and embedded inside electrospun polystyrene fibers and spin coated poly(methyl methacrylate) films. Porphyrin‐based metal‐organic framework PCN‐224, freshly activated, is also examined. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is a therapeutic modality that depends on the interaction of light, photosensitizers, and oxygen. The photon absorption and energy transfer process can lead to the Type II photochemical reaction of the photosensitizer and the production of singlet oxygen (1O2), which strongly oxidizes and reacts with biomolecules, ultimately causing oxidative damage to the target cells. Therefore, 1O2 is regarded as the key photocytotoxic species accountable for the initial photodynamic reactions for Type II photosensitizers. This article will provide a comprehensive review of 1O2 properties, 1O2 production, and 1O2 detection in the PDT process. The available 1O2 data of regulatory-approved photosensitizing drugs will also be discussed. [ABSTRACT FROM AUTHOR]

Cancer treatment continues to be a substantial problem due to tumor complexities and persistence, demanding novel therapeutic techniques. This review investigates the synergistic potential of combining photodynamic therapy (PDT) and tailored medication delivery technologies to increase mitochondrial toxicity and improve cancer outcomes. PDT induces selective cellular damage and death by activating photosensitizers (PS) with certain wavelengths of light. However, PDT's efficacy can be hampered by issues such as poor light penetration and a lack of selectivity. To overcome these challenges, targeted drug delivery systems have emerged as a promising technique for precisely delivering therapeutic medicines to tumor cells while avoiding off-target effects. We investigate how these technologies can improve mitochondrial targeting and damage, which is critical for causing cancer cell death. The combination method seeks to capitalize on the advantages of both modalities: selective PDT activation and specific targeted drug delivery. We review current preclinical and clinical evidence supporting the efficacy of this combination therapy, focusing on case studies and experimental models. This review also addresses issues such as safety, distribution efficiency, resistance mechanisms, and costs. The prospects of further research include advances in photodynamic agents and medication delivery technology, with a focus on personalized treatment. In conclusion, combining PDT with targeted drug delivery systems provides a promising frontier in cancer therapy, with the ability to overcome current treatment limits and open the way for more effective, personalized cancer treatments. [ABSTRACT FROM AUTHOR]

The use of organic molecules as photosensitizers in photoredox catalysis is an attractive research field as it has the potential to replace conventionally used photosensitizers, which are based on rare metals. In the context of light‐driven hydrogen evolution catalysis, the radical formation of two perylene monoimide dyes (PMIs) was studied by means of electron paramagnetic resonance (EPR) and UV/Vis spectroscopy. The PMIs were reduced and oxidized both photochemically and electrochemically to study the changes in absorption and EPR signature. A distinct differentiation between the two PMIs as well as a comparison between the oxidative and reductive processes can be made by EPR measurements. UV/Vis measurements showed different features under redox conditions. This study addresses a gap in understanding the radical intermediate formation during photocatalytic processes. [ABSTRACT FROM AUTHOR]

• Plant growth-promoting rhizobacteria (PGPR) are a considerable and favourable strategy to improve agriculture and mitigate abiotic stress. • To increase the efficacy of this approach, the utilization of He Ne laser radiation (L) and methylene blue (MB) as photosensitizer are commonly suggested to increase the efficiency of IAA-producing rhizobacterial strain Alcaligenes sp. E1 on maize growth under salt stress. • The use of treated PGPR under salt stress induced an increase in shoot length (44 %), root length (49 %), fresh weight (34 %), dry weight (45.6 %), chlorophyll a (51 %), and carotenoids (71 %) over the stressed control. • The results showed that irradiation of the tested bacterium by a 10 mW He Ne laser significantly increase IAA production compared to non-irradiated and photosensitized bacteria. • Irradiation of bacterial suspension increases the efficacy of bacteria to synthesize IAA. Plant growth-promoting rhizobacteria (PGPR) are a beneficial strategy to improve agriculture and mitigate abiotic stress. To increase the efficacy of this approach, the utilization of He Ne laser radiation (L) and methylene blue (MB) as photosensitizer is commonly suggested. This study evaluated the role of the IAA-producing rhizobacterial strain Alcaligenes sp. E1 on maize growth under salt stress (150 mM NaCl) with the application of laser and methylene blue. The results showed that treatment of Alcaligenes sp. E1 with red laser and methylene blue exhibited a maximum increase in shoot length (44 %), root length (49 %), fresh weight (34 %), dry weight (45.6 %), chlorophyll a (51 %), and carotenoids (71 %) over the stressed control. In addition, it demonstrated more activity to antioxidant activities (SOD, CAT, GSH, and TAC) and limited oxidative damage resulting from ROS formation. In conclusion, Alcaligenes sp. has a good ability to stimulate maize growth when applied with laser radiation and photosensitizer under normal and saline conditions. Thus, we propose that red laser and photosensitizer will have promising applications in crop biostimulation and sustainable agriculture. [ABSTRACT FROM AUTHOR]

In the past few years, there has been an increasing interest in mycosporines—UV-absorbing molecules—bringing important insights into their intrinsic properties as natural sunscreens. Herein, mycosporine-serinol and gadusol (enolate form)/gadusolate were exposed to UV radiation via a solar simulator and the photostability was assessed in pure water and different natural matrices like river, estuary and ocean water. In general, this study revealed that the photodegradation of gadusolate and mycosporine-serinol was higher in natural matrices than in pure water due to the generation of singlet oxygen on UV irradiation. In pure water, in terms of photostability, both gadusolate and mycosporine-serinol were found to offer good protection and high performance in terms of photodegradation quantum yield ((0.8 ± 0.2) × 10−4 and (1.1 ± 0.6) × 10−4, respectively). Nonetheless, the photostability of mycosporine-serinol was found to be superior to that of gadusolate in natural water, namely, ocean, estuary and river. The present work highlights how mycosporine-serinol and gadusolate resist photodegradation, and supports their role as effective and stable UV-B sunscreens. [ABSTRACT FROM AUTHOR]

This work aims to examine the application of ZnO/Curcumin nanocomposite materials, in which curcumin (natural dye) is used as a photosensitizer in the photocatalytic degradation of methylene blue (MB) under visible light irradiation. The ZnO/x% curcumin nanocomposite materials (with x = 3, 5, 7, 10 and 20) are prepared by the wet impregnation method. These nanocomposite materials are characterized using various techniques; including Fourier transform infrared spectroscopy, X-ray diffraction, ultraviolet–visible spectroscopy and scanning electron microscopy. Optimal MB degradation of ~ 99% was obtained with a concentration of 0.5 g L−1 of 5% curcumin/ZnO nanocomposite catalyst material, at natural pH and initial MB concentration of 10 mg L−1 for 90 min exposure to visible light irradiation. The kinetic indicates that the Langmuir–Hinshelwood (L–H) model is well adapted to the experimental data. Pseudo-first order kinetics were obtained with a rate constant (k) and half-life time ( t 1 / 2 ) of 0.0423 min−1 and 16 min. The significant improvement in the photocatalytic properties of ZnO under visible light irradiation induced by the addition of curcumin as a photosensitizer could be due to the increase in the concentration of reactive radical species in the solution, such as superoxide ( O 2 · - ) and hydroxyles ( OH · ). [ABSTRACT FROM AUTHOR]

Phototheranostics have captured growing attention for their undenying superiority over traditional cancer therapy treatments. The integration of all phototheranostics modalities from ensuring near-infrared absorption-emission properties to an efficient photodynamic therapy (PDT) behavior in a single molecule is a challenging task. Herein, we have achieved this by self-assembled northiosquaraine nanoparticles (TSQ-NPs) that exhibit high water dispersion ability, good biocompatibility, good optical behaviors, and a metal-free design. The synthesized TSQ-NPs have been found to exhibit one of the highest values of singlet oxygen quantum yield and appreciable photostability among the reported organic nanoparticles. The in vitro studies of TSQ-NPs on KB and HeLa cells suggest efficient cell uptake within an hour, a structure inherent mitochondrion targeting property, and ability to yield intracellular reactive oxygen species (ROS) under illumination of light that can be used for cell therapy applications. The excellent PDT effect induced by red light by nanoparticles originating from a single organic compound is promising for the future of cancer diagnostics, therapy, and molecular imaging. [ABSTRACT FROM AUTHOR]

Despite the advent of various medical interventions for cancer treatment, the disease continues to pose a formidable global health challenge, necessitating the development of new therapeutic approaches for more effective treatment outcomes. Photodynamic therapy (PDT), which utilizes light to activate a photosensitizer to produce cytotoxic reactive oxygen species (ROS) for eradicating cancer cells, has emerged as a promising approach for cancer treatment due to its high spatiotemporal precision and minimal invasiveness. However, the widespread clinical use of PDT faces several challenges, including the inefficient production of ROS in the hypoxic tumor microenvironment, the limited penetration depth of light in biological tissues, and the inadequate accumulation of photosensitizers at the tumor site. Over the past decade, there has been increasing interest in the utilization of photofunctional transition metal complexes as photosensitizers for PDT applications due to their intriguing photophysical and photochemical properties. This review provides an overview of the current design strategies used in the development of transition metal complexes as innovative phototherapeutics, aiming to address the limitations associated with PDT and achieve more effective treatment outcomes. The current challenges and future perspectives on the clinical translation of transition metal complexes are also discussed. [ABSTRACT FROM AUTHOR]

Ruthenium(II) polypyridyl complexes are being tested as potential anticancer agents in different therapies, which include conventional chemotherapy and light-activated approaches. A mechanistic study on a recently synthesized dual-action Ru(II) complex [Ru(bpy)2(sora)Cl]+ is described here. It is characterized by two mono-dentate leaving ligands, namely, chloride and sorafenib ligands, which make it possible to form a di-aquo complex able to bind DNA. At the same time, while the released sorafenib can induce ferroptosis, the complex is also able to act as a photosensitizer according to type II photodynamic therapy processes, thus generating one of the most harmful cytotoxic species, 1O2. In order to clarify the mechanism of action of the drug, computational strategies based on density functional theory are exploited. The photophysical properties of the complex, which include the absorption spectrum, the kinetics of ISC, and the character of all the excited states potentially involved in 1O2 generation, as well as the pathway providing the di-aquo complex, are fully explored. Interestingly, the outcomes show that light is needed to form the mono–aquo complex, after releasing both chloride and sorafenib ligands, while the second solvent molecule enters the coordination sphere of the metal once the system has come back to the ground-state potential energy surface. In order to simulate the interaction with canonical DNA, the di-aquo complex interaction with a guanine nucleobase as a model has also been studied. The whole study aims to elucidate the intricate details of the photodissociation process, which could help with designing tailored metal complexes as potential anticancer agents. [ABSTRACT FROM AUTHOR]

Three novel polypyridyl‐Co(III)‐vitamin B6 complexes viz., [Co(CF3‐phtpy)(SBVB6)]Cl (Co1), [Co(anthracene‐tpy)(SBVB6)]Cl (Co2), [Co(NMe2‐phtpy)(SBVB6)]Cl (Co3), where 4’‐(4‐(trifluoromethyl)phenyl)‐2,2’:6’,2’’‐terpyridine=CF3‐phtpy, 4’‐(anthracen‐9‐yl)‐2,2’:6’,2’’‐terpyridine=anthracene‐tpy;, 4‐([2,2’:6’,2’’‐terpyridin]‐4’‐yl)‐N,N‐dimethylaniline=NMe2‐phtpy, (E)‐5‐(hydroxymethyl)‐4‐(((2‐hydroxyphenyl)imino)methyl)‐2‐methylpyridin‐3‐ol=H2SBVB6 were successfully developed for aPDT (antibacterial photodynamic therapy) applications. Co1–Co3 exhibited an intense absorption band at ca. 435–485 nm, which is attributed to ligand‐to‐metal charge transfer and was beneficial for antibacterial photodynamic therapy. The distorted octahedral geometry of the complexes with CoIIIN4O2 core was evident from the DFT study. The visible light absorption ability and good photo‐stability of Co1–Co3 made them good photosensitizers for aPDT. Co1–Co3 displayed significant antibacterial responses against gram‐positive (S. aureus) and gram‐negative (E. coli) bacteria upon light exposure (10 J cm−2, 400–700 nm) and showed MIC values between 0.01–0.005 μg mL−1. The aPDT activities of these complexes were due to their ability to damage bacterial cell membranes via ROS generation. Overall, this study shows the photo‐triggered ROS‐mediated bacteria‐killing potential of Co(III) complexes. [ABSTRACT FROM AUTHOR]

Breast cancer stem cells (CSCs) are responsible for the occurrence, resistance, recurrence, invasion, and metastasis of tumors. However, even trace amounts of CSCs may lead to tumor resistance and recurrence, which fundamentally reduces the therapeutic efficiency of numerous anticancer drugs. Thus, the development of a therapeutic agent that can reduce the tumorigenicity of CSCs and overcome tumor resistance and recurrence is essential. Here a novel multifunctional prodrug T‐P is reported as a photosensitizer, which links phenothiazine drug with the synthesized aggregation‐induced emission photosensitizer T‐C via an ester bond. Importantly, this photosensitizer is found to be able to induce the pyroptosis of breast CSCs as well as to activate their death pathway protein phosphatase 2A to inhibit CSCs and systemic anti‐tumor effects. T‐P can rapidly target mitochondria and overlap with lysosomes after mitochondrial escape, and it can cause mitochondrial and lysosomal dysfunction. It releases reactive oxygen species through photoactivation, triggering pyroptosis‐mediated strong anti‐tumor immune response. On the 5th day of in vivo therapy of breast cancer, the primary tumor is eliminated and the growth of distant tumors is also inhibited. This research would provide an impetus as well as a new strategy for CSCs‐targeted cancer photoimmunotherapy and beyond. [ABSTRACT FROM AUTHOR]

Development of devices for production of H2 using light and a sustainable source of electrons may require the design of molecular systems combining a molecular catalyst and a photosensitizer. Evaluation of the efficiency of hydrogen production is commonly performed in homogeneous solution with a sacrificial electron donor and the report of the maximal turnover number vs catalyst (TONcatlim ${TON_{cat}^{\lim } }$). This figure of merit is strongly dependent on deactivation pathways and does not by itself provide a benchmarking for catalysts. In particular, when the photosensitizer degradation is the primary source of limitation, a kinetic model, rationalizing literature data, shows that a decrease of the catalyst concentration leads to an increase of TONcatlim ${TON_{cat}^{\lim } }$. It indicates that exceptionally high TONcatlim ${TON_{cat}^{\lim } }$ obtained at very low catalyst concentration shall not be considered as an indication of an exceptional catalytic system. We advocate for a systematic kinetic analysis in order to get a quantitative measure of the competitive pathways leading to TONcatlim ${TON_{cat}^{\lim } }$ values and to provide keys for performance improvement. [ABSTRACT FROM AUTHOR]

Molecular organic photocatalysts developed for use in chemical transformation reactions have gained momentum in recent years. In this study, six new triplet photosensitizers were prepared to determine their photocatalyst capabilities and chemical transformation abilities. The chemical structures of the synthesized orthogonal BODIPYs and their cyclotriphosphazene derivatives were analyzed and then their photophysical characteristics including the UV‐Vis absorption spectra, fluorescence emission spectra, fluorescence quantum yields, were investigated. The quantitative singlet oxygen formation was determined by chemical trapping using DPBF (diphenylisobenzofuran). In particular, cyclotriphosphazene derivative 12 having three BODIPY moieties showed efficient singlet oxygen production with high photostability and good molar extinction coefficient. The photo‐oxidation ratio constant of 1,5‐dihydroxynaphthalene (DHN) was calculated as 28.7×10−3 min−1 for compound 12 and at the end of 22.5 min., DHN converted to juglone with 100 % efficiency. In addition, the ability of the compounds to convert 1,3‐cyclohexadiene into peroxides in the presence of molecular oxygen and light was investigated and the conversion efficiency was determined by NMR technique. All compounds have been presented as photocatalysts for use in different synthetic photochemistry applications. [ABSTRACT FROM AUTHOR]

The development of activatable nanoplatforms to enhance diagnostic and therapeutic performance while minimizing side effects is of great significance in treatment of chronic hepatitis B (CHB). Here, we report a novel nanomaterial composed of graphitic carbon nitride (g-C3N4) and 5-aminolevulinic acid (5-ALA), onto which our newly synthesized compound 1 is loaded, forming 5-ALA/g-C3N4@1. This nanomaterial is highly pH-sensitive and can rapidly degrade in mildly acidic environments, enabling the release of its loaded photosensitizer and compound 1, exhibiting characteristics such as fluorescence recovery and increased singlet oxygen generation. We evaluated the bioactivity of this novel composite material and explored its mechanisms of action. The effect of 5-ALA/g-C3N4@1 on the levels of HBV DNA, HBsAg and HBeAg was evaluated by treatment of HepG2.2.15 cells with the system. Our results suggest that the system can effectively inhibit HBV replication for the treatment of CHB. This work presents a novel photosensitive carrier with excellent biocompatibility and therapeutic efficacy, offering new insights into CHB research. [ABSTRACT FROM AUTHOR]

The combination of photodynamic therapy (PDT) and pneumatotherapy is emerging as one of the most effective strategies for increasing cancer treatment efficacy while minimizing side effects. Photodynamic forces affect nitric oxide (NO) levels as activated photosensitizers produce NO, and NO levels in the tumor and microenvironment directly impact tumor cell responsiveness to PDT. In this paper, 3-benzenesulfonyl-4-(1-hydroxy ether)-1,2,5-oxadiazole-2-oxide NO donor–silicon phthalocyanine coupling (SiPc–NO) was designed and prepared into self-assembled nanoparticles (SiPc–NO@NPs) by precipitation method. By further introducing arginyl-glycyl-aspartic acid (RGD) on the surface of nanoparticles, NO-photosensitizer delivery systems (SiPc–NO@RGD NPs) with photo-responsive and tumor-targeting properties were finally prepared and preliminarily evaluated in terms of their formulation properties, NO release, and photosensitizing effects. Furthermore, high reactive oxygen species (ROS) generation efficiency and high PDT efficiency in two breast cancer cell lines (human MCF-7 and mouse 4T1) under irradiation were also demonstrated. The novel SiPc–NO@RGD NPs show great potential for application in NO delivery and two-photon bioimaging-guided photodynamic tumor therapy. [ABSTRACT FROM AUTHOR]

Triple hybrid nanocomplexes based on selenium (Se0) nanoparticles, cellulose polymer carrier (CPC), and the photosensitizer fotoditazine (FD) were synthesized with different sequences of component addition and ratios. The spectral characteristics of these triple nanocomplexes were compared with analogous characteristics of FD and double complexes of variable composition (FD/Se0, CPC/FD, and CPC/Se0) using spectral methods. The synthesized triple hybrid Se-containing nanocomplexes could be promising for photodynamic therapy and diagnostics. [ABSTRACT FROM AUTHOR]

Porphyrazines (Pzs) are porphyrin derivatives that show potential application as photosensitizers for photodynamic therapy (PDT), but are still far less explored in the literature. In this work, we evaluate how the photophysics and phototoxicity of the octakis(trifluoromethylphenyl)porphyrazine (H2Pz) against tumor cells can be modulated by coordination with Mg(II), Zn(II), Cu(II) and Co(II) ions. Fluorescence and singlet oxygen quantum yields for the Pzs were measured in organic solvents and in soy phosphatidylcholine (PC) liposomes suspended in water. While H2Pz and the respective complexes with Cu(II) and Co(II) showed very low efficiency to fluoresce and to produce 1O2, the Mg(II) and Zn(II) complexes showed significantly higher quantum yields in organic solvents. The fluorescence of these two Pzs in the liposomes was sensitive to the fluidity of the membrane, showing potential use as viscosity markers. The cytotoxicity of the compounds was tested in HaCaT (normal) and A431 (tumor) cells using soy PC liposomes as drug carriers. Despite the low 1O2 quantum yields in water, the Mg(II) and Zn(II) complexes showed IC50 values against A431 cells in the nanomolar range when activated with low doses of red LED light. Their phototoxicity was ca. three times higher for the tumor cells compared to the normal ones, showing promising application as photosensitizers for PDT protocols. Considering that H2Pz and the respective Co(II) and Cu(II) complexes were practically non-phototoxic to the cells, we demonstrate the importance of the central metal ion in the modulation of the photodynamic activity of porphyrazines. [ABSTRACT FROM AUTHOR]

Liposomes are widely used for smart delivery due to their biodegradability and biocompatibility. Recently, liposomes have been developed to respond to dual and multi-stimuli. This development leads to the potential for superior in vitro and in vivo drug delivery in the future. In this study, egg PC liposomes responsive to temperature, oxidation, and NIR irradiation were prepared by modifying the liposomal membranes with poly(hydroxyethyl acrylate-co-ethyl vinyl sulfide) (P(HEA-co-EVS)) and including indocyanine green (ICG) in the liposomes.The copolymer was found to exhibit a lower critical solution temperature (LCST) and it was oxidizable and surface-active.On the TEM photos of the liposomes, multi-lamellar vesicles were found and the size was in accordance with the hydrodynamic diameter. The liposomes released their payload in response to H2O2 concentration possibly because the EVS was oxidized by the oxidizing agent. The liposome exhibited a temperature-responsive release possibly due to the thermal contraction of the copolymer chains.In addition, the release was triggered when a near-infrared(NIR) laser was irradiated to the liposome suspensions. Under NIR irradiation, the photosensitizer (i.e. ICG) can generate heat and reactive oxygen species, which, in turn, would induce the conformational and polarity change of the polymer chains, leading to a release. [ABSTRACT FROM AUTHOR]

Polyamines play a pivotal role in cancer cell proliferation. The excessive polyamine requirement of these malignancies is satisfied through heightened biosynthesis and augmented extracellular uptake via the polyamine transport system (PTS) present on the cell membrane. Meanwhile, photodynamic therapy (PDT) emerges as an effective anti-cancer treatment devoid of drug resistance. Recognizing these intricacies, our study devised a novel polyamine-derived photosensitizer (PS) for targeted photodynamic treatment, focusing predominantly on pancreatic cancer cells. We synthesized and evaluated novel spermine-derived fluorescent probes (N2) and PS (N3), exhibiting selectivity towards pancreatic cancer cells via PTS. N3 showed minimal dark toxicity but significant phototoxicity upon irradiation, effectively causing cell death in vitro. A significant reduction in tumor volume was observed post-treatment with no pronounced dark toxicity using the pancreatic cancer CDX mouse model, affirming the therapeutic potential of N3. Overall, our findings introduce a promising new strategy for cancer treatment, highlighting the potential of polyamine-derived PSs in PDT. [ABSTRACT FROM AUTHOR]

This study investigates hydrogels based on 2-Acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS) copolymers, incorporating N-hydroxyethyl acrylamide (HEA) and 3-sulfopropyl acrylate potassium salt (SPA). The addition of HEA and SPA is designed to fine-tune the hydrogels' water absorption and mechanical properties, ultimately enhancing their characteristics and expanding their potential for biomedical applications. A copolymer of AMPS, 2-carboxyethyl acrylate (CEA) combined with methacrylic acid (MAA) as poly(AMPS-stat-CEA-stat-MAA, PACM), was preliminarily synthesized. CEA and MAA were modified with allyl glycidyl ether (AGE) through ring-opening, yielding macromers with pendant allyl groups (PACM-AGE). Copolymers poly(AMPS-stat-HEA-stat-CEA-stat-MAA) (PAHCM) and poly(AMPS-stat-SPA-stat-CEA-stat-MAA) (PASCM) were also synthesized and modified with AGE to produce PAHCM-AGE and PASCM-AGE macromers. These copolymers and macromers were characterized by 1H NMR, FT-IR, and GPC, confirming successful synthesis and functionalization. The macromers were then photocrosslinked into hydrogels and evaluated for swelling, water content, and mechanical properties. The results revealed that the PASCM-AGE hydrogels exhibited superior swelling ratios and water retention, achieving equilibrium water content (~92%) within 30 min. While the mechanical properties of HEA and SPA containing hydrogels show significant differences compared to PACM-AGE hydrogel (tensile strength 2.5 MPa, elongation 47%), HEA containing PAHCM-AGE has a higher tensile strength (5.8 MPa) but lower elongation (19%). In contrast, SPA in the PASCM-AGE hydrogels led to both higher tensile strength (3.7 MPa) and greater elongation (92%), allowing for a broader range of hydrogel properties. An initial study on drug delivery behavior was conducted using PACM-AGE hydrogels loaded with photosensitizers, showing effective absorption, release, and antibacterial activity under light exposure. These AMPS-based macromers with HEA and SPA modifications demonstrate enhanced properties, making them promising for wound management and drug delivery applications. [ABSTRACT FROM AUTHOR]

Cigarette beetles Lasioderma serricorne (Fabricius, 1792) and saw-toothed grain beetles Oryzaephilus surinamensis (Linnaeus, 1758) are considered serious stored grain pests. Developing silica nanoparticles (SNs) coated with the most effective and persistent photosensitizer is a viable alternative to current synthetic chemical pesticides. Chemical characterization confirmed the conjugation process between SNs and rose bengal (RB) and formation of SNs photosensitizer rose bengal (SNP-RB). Additionally, bioassays were performed to determine the impact of the median-lethal concentration (LC50) of the three substances against pests. The corresponding LC50 values against L. serricorne and O. surinamensis were 5.14, 20.32, 50.60 and 9.79, 28.93, 106.29 for SNP-RB, SNs and RB respectively. Therefore, the toxicity of these tested compounds after three hours of sun light exposure could be descendingly arranged in order as follows: SNP-RB, SNs and RB. The relative percentages of mineral contents were detected in the whole body tissue of L. serricorne and revealed the existence of nine elements in untreated adults, 11 elements in adults treated with RB as well as nine elements in adults treated with SNP-RB. Silicon was the least abundant element in both controls as well as adults treated with SNP-RB, Sulphur was the least abundant element in adults treated with RB and carbon was detected as the most abundant element in all treatments. Considering O. surinamesis, ten elements existed in untreated adults, 11 elements in adults treated with RB, whereas ten elements were found in adults treated with SNP-RB. Carbon was the most abundant element in all treatments, whereas calcium appeared as the least abundant element in SNP-RB. [ABSTRACT FROM AUTHOR]

Cigarette beetles Lasioderma serricorne (Fabricius, 1792) and saw-toothed grain beetles Oryzaephilus surinamensis (Linnaeus, 1758) are considered serious stored grain pests. Developing silica nanoparticles (SNs) coated with the most effective and persistent photosensitizer is a viable alternative to current synthetic chemical pesticides. Chemical characterization confirmed the conjugation process between SNs and rose bengal (RB) and formation of SNs photosensitizer rose bengal (SNP-RB). Additionally, bioassays were performed to determine the impact of the median-lethal concentration (LC50) of the three substances against pests. The corresponding LC50 values against L. serricorne and O. surinamensis were 5.14, 20.32, 50.60 and 9.79, 28.93, 106.29 for SNP-RB, SNs and RB respectively. Therefore, the toxicity of these tested compounds after three hours of sun light exposure could be descendingly arranged in order as follows: SNP-RB, SNs and RB. The relative percentages of mineral contents were detected in the whole body tissue of L. serricorne and revealed the existence of nine elements in untreated adults, 11 elements in adults treated with RB as well as nine elements in adults treated with SNP-RB. Silicon was the least abundant element in both controls as well as adults treated with SNP-RB, Sulphur was the least abundant element in adults treated with RB and carbon was detected as the most abundant element in all treatments. Considering O. surinamesis, ten elements existed in untreated adults, 11 elements in adults treated with RB, whereas ten elements were found in adults treated with SNP-RB. Carbon was the most abundant element in all treatments, whereas calcium appeared as the least abundant element in SNP-RB. [ABSTRACT FROM AUTHOR]

Antimicrobial photodynamic therapy uses photosensitizers to produce reactive oxygen species under light exposure to inhibit pathogenic bacteria. Although its application in the management of oral infectious diseases has increased over recent years, it is limited by inadequate tissue and biofilm penetration and suboptimal bioavailability exhibited by individual photosensitizers. These challenges can potentially be surmounted through the integration of nanomaterials, such as polymers, metals and metal oxides, metal-organic frameworks, and carbon and silicon nanomaterials. Polymers allow the controlled release of photosensitizers through structural adjustments but have low stability, while metals and metal oxides possess strong antibacterial properties but can be potentially toxic. Meanwhile, metal-organic frameworks have flexible structures and multifunctionality but have low stability and potential toxicity. Moreover, carbon and silicon nanomaterials, despite exhibiting excellent antibacterial properties and biocompatibility, have limited application due to high production costs. Materials with inherent antibacterial properties, such as chitosan and graphene oxide, have broader application prospects, as they can form multimodal antibacterial platforms with photosensitizers, enhancing the antibacterial effects and eliminating infections. Future research could incorporate other functional materials, such as anti-inflammatory agents and immunomodulatory materials, to construct comprehensive therapeutic nanoplatforms for the treatment of oral infectious diseases.

Sheeja S Rajan, Rahul Chandran, Heidi Abrahamse Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South AfricaCorrespondence: Sheeja S Rajan; Heidi Abrahamse, Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa, Email srajan@uj.ac.za; habrahamse@uj.ac.zaAbstract: Hypocrellin-based photodynamic therapy (PDT) is developing as a viable cancer therapeutic option, especially when enhanced by nanoconjugation. This review investigates the methods by which nano-conjugated hypocrellin enhances therapeutic efficacy and precision when targeting cancer cells. These nanoconjugates encapsulate or covalently bind hypocrellin photosensitizers (PSs), allowing them to accumulate preferentially in malignancies. When activated by light, the nanoconjugates produce singlet oxygen and other reactive oxygen species (ROS), resulting in oxidative stress that selectively destroys cancer cells while protecting healthy tissues. We look at how they can be used to treat a variety of cancers. Clinical and preclinical studies show that they have advantages such as increased water solubility, improved tumor penetration, longer circulation times, and tailored delivery, all of which contribute to fewer off-target effects and overall toxicity. Ongoing research focuses on improving these nanoconjugates for better tumor targeting, drug release kinetics, and overcoming biological obstacles. Furthermore, the incorporation of developing technologies such as stimuli-responsive nanocarriers and combination therapies opens exciting opportunities for enhancing hypocrellin-based PDT. In conclusion, the combination of hypocrellin and nanotechnology constitutes a significant approach to cancer treatment, increasing the efficacy and safety of PDT. Future research will seek to create conjugates including hypocrellin, herceptin, and gold nanoparticles to induce apoptosis in human breast cancer cells in vitro, opening possibilities for therapeutic applications.Keywords: hypocrellin, cancer, photodynamic therapy, photosensitizer, nanoparticles

Abstract New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude $$\:{10}^{6}$$ M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable.

Objectives. To synthesize Pt-containing derivatives of natural chlorins as potential agents for the combination therapy in oncology. Platinum compounds are known to occupy an important place as chemotherapeutic agents in the treatment of oncological diseases. However, Pt(II) complexes are highly toxic to the body and are not selectively accumulated in tumor cells. If photodynamic and chemotherapy methods are combined in a single drug, the pigments are responsible for the selectivity of conjugate accumulation in the tumor, while a chemotherapeutic agent based on Pt(II) complexes is responsible for the cytotoxic effect on tumor cells. This will not affect healthy cells and thereby minimize the systemic toxicity of the drug to the body.Methods. Methods for the synthesis of pyridine-containing derivatives of natural chlorins and their metal complexes for use as potential binary agents in oncology were applied. As part of the study, the structures of the compounds obtained were confirmed by mass spectrometry, nuclear magnetic resonance spectroscopy, ultraviolet spectroscopy, and high-resolution chromatography-mass spectrometry. Preparative methods, including thin-layer and column chromatography, centrifugation and recrystallization, were used to isolate and purify the compounds obtained.Results. Platinum(II) complexes of pyridine-containing derivatives of natural chlorins were obtained for application in combination therapy in oncology. The schemes for synthesizing the target photosensitizers were optimized, in order to increase the yields and for subsequent transfer to industrial sites.Conclusions. It was found that pyridine-containing derivatives of natural chlorins could be obtained in high yields, that they possess chelating properties for platinum, and can be considered as binary agents in cancer therapy after successful preclinical trials.

The aim of the study was to present various types of radiation that can increase the effectiveness of combined photodynamic therapy (PDT) for malignant and premalignant lesions. Material and Methods. The Web of Science, Scopus, MedLine, Library, and RSCI databases were used for finding publications on this topic, mainly over the last 10 years. Of 230 sources, 64 were included in the review. Results. Photodynamic therapy is a new cancer treatment technology that has become increasingly popular in recent years. It is often an alternative method of treating cancer when there is a high risk of side effects and complications during traditional treatments such as surgery, radiation therapy and chemotherapy. PDT requires a photosensitizer, light energy, and oxygen to create reactive oxygen species that destroy cancer cells. This review examines the basic principles and mechanisms of PDT used alone and in combination with other traditional therapies. Despite the fact that PDT is an effective and non-invasive cancer treatment, it has some limitations, such as low light penetration depth, ineffective photosensitizers and tumor hypoxia. Our study examines new strategies that use other energy sources, such as infrared- and x-rays, ultrasound, as well as electric and magnetic fields, to enhance the PDT effect and overcome its limitations. Great hopes are also associated with the use of a combination of PDT and neutron capture therapy (NСT). Currently, chlorin derivatives associated with boron carriers have been developed. They can be used for both fluorescence diagnostics and PDT, as well as for NСT. The synthesized compounds have a high selectivity of accumulation in the tumor. To date, encouraging preclinical results of high efficiency of combined use of NСT and PDT have already been obtained. Conclusion. Combination with various energy sources is a key factor for further development of PDT. Future research aimed at overcoming the limitations of PDT will contribute to unlocking the full potential of this technology in clinical practice.

Abstract Singlet oxygen is considered an important cell damaging agent due to its propensity to react with organic compounds. This drives the interest in developing methods for determination of 1O2. Simplicity of application and high sensitivity makes fluorescent probes a popular choice for in vivo 1O2 detection. Despite its proclaimed cell-impermeability, the commercially available Singlet Oxygen Sensor Green (SOSG) is widely applied to support assertions of 1O2 involvement in cell and tissue damage. Our investigation, however, demonstrate that different microbial species and cancer cells become fluorescent when exposed to SOSG under conditions which exclude generation of 1O2. Cells, permeabilized with chlorhexidine or by heat exposure under anaerobic conditions, exhibited SOSG fluorescence. Permeabilized cells could be stained with SOSG even 24 h post-permeabilization. Since SOSG is cell impermeable, the main factor that led to fluorescent staining was plasma membrane damage. Spectral analyses of different batches of SOSG revealed that SOSG endoperoxide (SOSG-EP) did not increase even after prolonged storage under the recommended conditions. The commercial preparations of SOSG, however, were not SOSG-EP free, which can produce erroneous results when SOSG staining is used as a proof of singlet oxygen production in vivo.

AbstractNeurological disorders such as neurodegenerative diseases and nervous system tumours affect more than one billion people throughout the globe. The physiological sensitivity of the nervous tissue limits the application of invasive therapies and leads to poor treatment and prognosis. One promising solution that has generated attention is Photodynamic therapy (PDT), which can potentially revolutionise the treatment landscape for neurological disorders. PDT attracted substantial recognition for anticancer efficacy and drug conjugation for targeted drug delivery. This review thoroughly explained the basic principles of PDT, scientific interventions and advances in PDT, and their complicated mechanism in treating brain-related pathologies. Furthermore, the merits and demerits of PDT in the context of neurological disorders offer a well-rounded perspective on its feasibility and challenges. In conclusion, this review encapsulates the significant potential of PDT in transforming the treatment landscape for neurological disorders, emphasising its role as a non-invasive, targeted therapeutic approach with multifaceted applications.

Relevance. The development of antimicrobial drugs and alternative methods, technologies and means of prevention, diagnosis and treatment of human infectious diseases caused by antibiotic-resistant microorganisms is one of the priorities of ensuring the biological safety of the country. Aims. To evaluate the bactericidal activity of tetrapyrrole macroheterocycles (porphyrins) at different light irradiation durations in relation to staphylococci, in vitro. Materials and methods. Studied strains of microorganisms: museum strains of microorganisms – S. aureus ATCC 29213, S. epidermidis ATCC 14990 and antibiotic-resistant strains of bacteria of the genus Staphylococcus (n=18) isolated from clinical biomaterial and from environmental objects in a medical organization. The studied chemical compounds are three different compounds of water-soluble asymmetrically substituted porphyrins containing heterocyclic fragments on the periphery of the porphyrin cycle (residues of benzoxazole, N-methylbenzimidazole and benzothiazole). Results. The activity of all three porphyrin compounds in relation to museum strains of staphylococcus and 77.8% of clinical antibiotic-resistant strains (n=14; 95% CI 20.1-97.5) turned out to be maximal (complete lysis) after 10 minutes of irradiation. Conclusions. The tested tetrapyrrole macroheterocycles (porphyrins) exhibit bactericidal activity against museum and clinical strains of staphylococcus, with different levels of antibiotic resistance, which determines Keywords: antibiotic resistance, water-soluble porphyrin, photodynamic inactivation, photosensitizer, photochemistry, staphylococci No conflict of interest to declare.

Abstract Background Medicinal plant-mediated combinational therapies have gained importance globally due to minimal side effects and enhanced treatment outcomes compared to single-drug modalities. We aimed to analyze the cytotoxic potential of each conventional treatment i.e., photodynamic therapy (PDT), chemotherapy (doxorubicin hydrochloride; Dox-HCl) with or without various concentrations of medicinal plant extracts (PE) on soft tissue cancer Rhabdomyosarcoma (RD) cell line. Methods The Rhabdomyosarcoma (RD) cell line was cultured and treated with Photosensitizer (Photosense (AlPc4)), Chemo (Dox-HCl), and their combinations with different concentrations of each plant extract i.e., Thuja occidentalis, Moringa oleifera, Solanum surattense. For the source of illumination, a Diode laser (λ = 630 nm ± 1 nm, Pmax = 1.5 mW) was used. Photosensitizer uptake time (∼ 45 min) was optimized through spectrophotometric measurements (absorption spectroscopy). Drug response of each treatment arm was assessed post 24 h of administration using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5- 5-diphenyl-2 H- tetrazolium bromide (MTT) assay. Results PE-mediated Chemo-Photodynamic therapy (PDT) exhibited synergistic effects (CI

This comprehensive research has explored the potential of enhancing dye-sensitized solar cells (DSSC) by harnessing environmentally friendly natural dyes, such as chlorophyll pigments from pandanus (664.1 nm) and papaya leaves (664.0 nm), as well as betacyanin pigments from sappan-mangosteen (536.2 nm). Electrochemical analyses elucidated the energy band gaps, revealing a hierarchy with the smallest band gap observed for papaya leaves (1.387 eV), followed closely by sappan-mangosteen (1.389 eV) and pandan leaves (1.396 eV). This research effectively addressed the persistent issue of electrolyte leakage in DSSC development by introducing a polymer electrolyte derived from polyvinylidene fluoride (PVDF) through electrospinning and phase inversion techniques. SEM characterization results and thermogravimetric analysis underscored the superior characteristics and high thermal stability of the PVDF nanofiber polymer for DSSC applications. The study's pivotal findings underscore the remarkable DSSC performance achieved with chlorophyll pigment from papaya leaves, reaching 1.31% efficiency without a polymer electrolyte. Moreover, the sappan-mangosteen dye emerged as a promising contender with the highest efficiency values when applied with polymer electrolyte, recording rates of 1.17% for PVDF NF and 0.95% for PVDF, which are notably comparable to the efficiency of liquid electrolyte at 1.26%.

The design of near‐infrared photosensitizers with high photodynamic and photothermal synergistic therapeutic properties is of great significance for tumor therapy. In this study, An‐cyclic‐BDP with excellent near‐infrared absorption (ε = 1.94 × 105 m−1 cm−1 at 804 nm) is prepared using a dual strategy of twisted π‐conjugated system induction (T‐π‐CSI) and spin‐orbit charge transfer (SOCT). Theoretical calculations, steady‐state and transient absorption spectra are used to investigate the intrinsic regulatory mechanisms between molecular structure and intersystem crossing (ISC) capacity. The results indicate that the application of the T‐π‐CSI and SOCT approach can be superimposed to increase ISC capacity and the triplet lifetime of An‐cyclic‐BDP (τ = 2961 ps). Electron paramagnetic resonance (EPR) results confirm that An‐cyclic‐BDP has the ability to generate hydroxyl radical (·OH) and singlet oxygen (1O2). Furthermore, the calculated 1O2 yield of An‐cyclic‐BDP is found to be 13%. The experimental results of the photothermal conversion indicates that An‐cyclic‐BDP exhibits a photothermal conversion efficiency of up to 48%. In vitro cell experiments demonstrate that An‐cyclic‐BDP‐NPs, constructed by encapsulating An‐cyclic‐BDP with DSPE‐mPEG2000, exhibit excellent biocompatibility and tumor cell‐killing ability. Therefore, the strong near‐IR absorption photosensitizer prepared in this study exhibits significant potential for application in the area of photodynamic and photothermal synergistic therapy. [ABSTRACT FROM AUTHOR]

A modular synthesis of novel series of 1,7‐difluorinated BODIPYs has been elaborated. First, the acid‐catalyzed condensation of ethyl 3‐aryl‐4‐fluoro‐1H‐pyrrole‐2‐carboxylates with aromatic aldehydes gives the corresponding dipyrromethane‐1,9‐dicarboxylates. The latter are subjected to the exhaustive reduction with lithium aluminum hydride to transform the ester moieties into methyl groups. The subsequent oxidation of the resulting 1,9‐dimethylated dipyrromethanes followed by the boron difluoride complexation afforded a family of novel core‐fluorinated BODIPYs in up to 74 % yield. Photophysical properties of the resulting BODIPYs were tuned by varying of the starting fluoropyrroles and aromatic aldehydes and were studied by UV‐visible and fluorescence spectroscopy. As a result, the fluorescence quantum yields of the obtained compounds reached up to 99 %. In addition, their ability to generate singlet oxygen and electrochemical properties were also evaluated. As a result, a new promising family of fluorophores with a good combination of the fluorescence and photosensitizing properties was obtained. It was found that conversion of ester groups into methyl ones at the 3,5‐positions of the BODIPY core is a crucial step toward fluorescence enhancement. In addition, DFT calculations were performed to elucidate a relationship between electronic structure, geometry and photophysical properties of these BODIPYs. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is an increasing challenge in semen preservation of breeding animals, especially in the porcine species. Bacteria are a natural component of semen, and their growth should be inhibited to protect sperm fertilizing capacity and the female's health. In pig breeding, where semen is routinely stored at 17°C in the liquid state, alternatives to conventional antibiotics are urgently needed. Photodynamic inactivation (PDI) of bacteria is a well-established tool in medicine and the food industry but this technology has not been widely adopted in semen preservation. The specific challenge in this setting is to selectively inactivate bacteria while maintaining sperm integrity and functionality. The aim of this study was to test the principle of PDI in liquid stored boar semen using the photosensitizer 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) and a white light LED-setup. In the first step, photophysical experiments comprising singlet oxygen phosphorescence kinetics of TMPyP and determination of the photosensitizer triplet time revealed a sufficiently high production of reactive singlet oxygen in the Androstar Premium semen extender, whereas seminal plasma acted as strong quencher. In vitro experiments with extended boar semen showed that the established PDI protocol preserves sperm motility, membrane integrity, DNA integrity, and mitochondrial activity while efficiently reducing the bacteria below the detection limit. A proof-of-concept insemination study confirmed the in vivo fertility of semen after photodynamic treatment. In conclusion, using the PDI approach, an innovative tool was established that efficiently controls bacteria growth in extended boar and maintains sperm fertility. This could be a promising contribution to the One Health concept with the potential to reduce antimicrobial resistance in animal husbandry. [ABSTRACT FROM AUTHOR]

Herein, we report a novel flavin analogue as singular chemical component for lysosome bioimaging, and inherited photosensitizer capability of the flavin core was demonstrated as a promising candidate for photodynamic therapy (PDT) application. Fine‐tuning the flavin core with the incorporation of methoxy naphthyl appendage provides an appropriate chemical design, thereby offering photostability, selectivity, and lysosomal colocalization, along with the aggregation‐induced emissive nature, making it suitable for lysosomal bioimaging applications. Additionally, photosensitization capability of the flavin core with photostable nature of the synthesized analogue has shown remarkable capacity for generating reactive oxygen species (ROS) within cells, making it a promising candidate for photodynamic therapy (PDT) application. [ABSTRACT FROM AUTHOR]

Resistant biofilms formed by Staphylococcus aureus on medical devices pose a constant medical threat. A promising alternative to tackle this problem is photodynamic inactivation (PDI). This study focuses on a polyurethane (PU) material with an antimicrobial surface consisting of a composite based on silicate, polycation, and erythrosine B (EryB). The composite was characterized using X-ray diffraction and spectroscopy methods. Anti-biofilm effectiveness was determined after PDI by calculation of CFU mL−1. The liquid PU precursors penetrated a thin silicate film resulting in effective binding of the PU/silicate composite and the PU bulk phases. The incorporation of EryB into the composite matrix did not significantly alter the spectral properties or photoactivity of the dye. A green LED lamp and laser were used for PDI, while irradiation was performed for different periods. Preliminary experiments with EryB solutions on planktonic cells and biofilms optimized the conditions for PDI on the nanocomposite materials. Significant eradication of S. aureus biofilm on the composite surface was achieved by irradiation with an LED lamp and laser for 1.5 h and 10 min, respectively, resulting in a 10,000-fold reduction in biofilm growth. These results demonstrate potential for the development of antimicrobial polymer surfaces for modification of medical materials and devices. [ABSTRACT FROM AUTHOR]

The efficient generation of reactive oxygen species (ROS) is crucial for the photodynamic therapy (PDT) effect. The D‐π‐A molecular engineering strategy can effectively separate the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) distribution to achieve a smaller energy gap thereby facilitating ROS generation of photosensitizers (PSs). Incorporating heterocycles as π‐bridges can not only extend the conjugation system with improving the degree of π‐delocalization but also effectively accelerate the intersystem crossing process. Herein, a N‐heterocycle purine is innovatively integrated into the D‐π‐A structure as a π‐bridge, which significantly enhances the photodynamic performance by achieving high levels of Type I and Type II ROS generation. The most potent TPM‐QN2 is obtained by modulating the electron‐withdrawing ability of the acceptor (quinolinium), with a 1O2 yield of 9.32, which is the highest yield reported to date. Furthermore, these purine‐based PSs exhibit excellent capabilities in promoting cell photodynamic ablation and inhibiting tumor tissue growth. This novel approach of introducing natural heterocycles provides a promising avenue for developing high‐performance PSs and promoting tumor phototherapy. [ABSTRACT FROM AUTHOR]

In this work, a computational investigation of ferrocene (Fc)‐based compounds FcCH2CS3CH2Fc (1) and FcCH2SSCH2Fc (2) sensitizer for dye‐sensitized solar cells (DSSCs) has been carried out to comprehend the photophysical and photo‐electrochemical properties. The density functional theory (DFT) and time‐dependent DFT (TD‐DFT) were employed to assess the photovoltaic parameters of the compounds. The frontier molecular orbital analysis revealed the electron density distribution at HOMO and LUMO, which clearly demonstrates the charge separation within the compounds. The electronic absorption spectra are simulated using the TD‐DFT method to comprehend the ability of the compounds to harvest sunlight and efficiently act as photosensitizer. Simulation of electronic spectra of dye@TiO2 cluster exhibits that the absorption coefficient of compound 1 is higher than compound 2 due to the greater extent of charge transfer from the dye to the TiO2 cluster. These computational findings are corroborated by the reported photovoltaic performance of the compounds. [ABSTRACT FROM AUTHOR]