Search Results (8)

Hypericin (Hyp) is a naturally occurring photosensitizer (PS) exhibiting a broad spectrum of biological activities. However, its high hydrophobicity significantly limits its medical applicability. This study aimed to develop an efficient method for extracting Hyp from Hypericum perforatum L. biomass and to obtain its water-soluble micellar formulation. A protocol for Hyp isolation from the aerial parts of the plant was established, involving a preliminary defatting step using a Soxhlet apparatus, followed by ultrasonic-assisted extraction with acetone. The water-soluble formulation was prepared via the thin-film hydration method using the nonionic block copolymer Pluronic F-127. The resulting micelles demonstrated colloidal stability, with a mean hydrodynamic diameter of approximately 30 nm. A high Hyp loading efficiency was achieved, with an encapsulation efficiency (EE) of 95.4 ± 2.7%, yielding a concentration of 600.6 ± 16.6 µM within the micellar formulation. In vitro biological studies were performed using the murine GL261 glioblastoma cell line. The micellar Hyp formulation exhibited efficient time-dependent cellular accumulation and photoinduced cytotoxicity, with no observable dark toxicity. The proposed method enables the production of a stable Hyp formulation that retains its photosensitizing properties, thereby opening promising avenues for its application in photodynamic and sonodynamic therapies. Full article

Reactive oxygen species (ROS)-mediated cancer therapy has attracted extensive attention due to its high spatiotemporal selectivity and minimal side effects. Herein, we report a nonanuclear Pd-based coordination cage of Pd₆-TMPP(Ni), constructed from Ni-chelated TMPP(Ni) as the metalloligand and Pd²⁺ ions (H₂TMPP = meso-tetrakis (6-methylpyridin-3-yl) porphyrin). Pd₆-TMPP(Ni) integrates dual ROS-generation for cancer therapy, viz., hydroxyl radical (•OH) production and photoinduced singlet oxygen (¹O₂) generation. In vitro cytotoxicity assays against cancer cell lines NCI-H82 (lung cancer), A549 (lung cancer), KYSE-510 (esophageal cancer), and Te-1 (esophageal cancer) reveal its potent dark toxicity (IC₅₀: 1.9–2.1 μmol L⁻¹) and phototoxicity (IC₅₀: 0.8–1.5 μmol L⁻¹), which is attributed to enhanced intracellular ROS accumulation. This work develops a versatile therapeutic platform that harnesses Ni-induced •OH for chemodynamic therapy (CDT) and porphyrin-generated ¹O₂ for photodynamic therapy (PDT), thereby mitigating the oxygen dependence of conventional PDT. Full article

Fine powders of erbium niobate-tantalates ErNb_xTa_1−xO₄ (x = 0; 0.1; 0.3; 0.5; 0.7; 0.9; 1) have been synthesized by the liquid-phase method in this study. Ceramic samples have been prepared using conventional sintering from these powders. Rietveld refinement of XRD patterns of polycrystals determined the phase composition and clarified the parameters of the phase structure of ErNb_xTa_1−xO₄ solid solutions depending on the Nb/Ta ratio. The morphological features of the microstructure of erbium niobate-tantalate ceramics have been studied. Their mechanical properties, strength characteristics (Young’s modulus, microhardness) and critical stress intensity factor of the first kind K_IC have been estimated. The photoluminescent properties of ceramic solid solutions of erbium niobate-tantalates depending on the composition have been studied. Dark and photoinduced toxicity of finely dispersed ErNbO₄ powders have been studied in relation to Gram-positive, Gram-negative and spore-forming microorganisms. The best indicators of antibacterial activity of ErNbO₄ have been demonstrated in relation to Gram-positive cells of Micrococcus sp. The discovered properties open up the possibility of not only traditional use as functional materials, but also the use of these materials for disinfection of surfaces, water and biological tissues. Full article

Photodynamic therapy (PDT) in oncology is characterized by low invasiveness, minimal side effects, and little tissue scarring. Increasing the selectivity of PDT agents toward a cellular target is a new approach intended to improve this method. This study is devoted to the design and synthesis of a new conjugate based on meso-arylporphyrin with a low-molecular-weight tyrosine kinase inhibitor, Erlotinib. A nano-formulation based on Pluronic F127 micelles was obtained and characterized. The photophysical and photochemical properties and biological activity of the studied compounds and their nano-formulation were studied. A significant, 20–40-fold difference between the dark and photoinduced activity was achieved for the conjugate nanomicelles. After irradiation, the studied conjugate nanomicelles were 1.8 times more toxic toward the EGFR-overexpressing cell line MDA-MB-231 compared to the conditionally normal NKE cells. The IC50 was 0.073 ± 0.014 μM for the MDA-MB-231 cell line and 0.13 ± 0.018 μM for NKE cells after irradiation for the target conjugate nanomicelles. Full article

The large number of deaths induced by carcinoma and infections indicates that the need for new, better, targeted therapy is higher than ever. Apart from classical treatments and medication, photodynamic therapy (PDT) is one of the possible approaches to cure these clinical conditions. This strategy offers several advantages, such as lower toxicity, selective treatment, faster recovery time, avoidance of systemic toxic effects, and others. Unfortunately, there is a small number of agents that are approved for usage in clinical PDT. Novel, efficient, biocompatible PDT agents are, thus, highly desired. One of the most promising candidates is represented by the broad family of carbon-based quantum dots, such as graphene quantum dots (GQDs), carbon quantum dots (CQDs), carbon nanodots (CNDs), and carbonized polymer dots (CPDs). In this review paper, these new smart nanomaterials are discussed as potential PDT agents, detailing their toxicity in the dark, and when they are exposed to light, as well as their effects on carcinoma and bacterial cells. The photoinduced effects of carbon-based quantum dots on bacteria and viruses are particularly interesting, since dots usually generate several highly toxic reactive oxygen species under blue light. These species are acting as bombs on pathogen cells, causing various devastating and toxic effects on those targets. Full article

In photodynamic therapy (PDT), a photosensitizer (PS) excited with a specific wavelength, and in the presence of oxygen, gives rise to photochemical reactions that lead to cell damage. Over the past few years, larval stages of the G. mellonella moth have proven to be an excellent alternative animal model for in vivo toxicity testing of novel compounds and virulence testing. In this article, we report a series of preliminary studies on G. mellonella larvae to evaluate the photoinduced stress response by a porphyrin (PS) (TPPOH). The tests performed evaluated PS toxicity on larvae and cytotoxicity on hemocytes, both in dark conditions and following PDT. Cellular uptake was also evaluated by fluorescence and flow cytometry. The results obtained demonstrate how the administration of PS and subsequent irradiation of larvae affects not only larvae survival rate, but also immune system cells. It was also possible to verify PS’s uptake and uptake kinetics in hemocytes, observing a maximum peak at 8 h. Given the results obtained in these preliminary tests, G. mellonella appears to be a promising model for preclinical PS tests. Full article

The low-toxicity treatment of chromium-containing wastewater represents an important way of addressing key environmental problems. In this study, a core-shell structural ZIF-8@TiO₂ photocatalyst was synthesized by a simple one-step hydrothermal method. The obtained composite photocatalyst possessed improved photocatalytic activity compared with TiO₂. The results indicated that the optimized ZIF-8@TiO₂ composite exhibited the highest removal efficiency with 93.1% of Cr(VI) after 120 min under UV-vis irradiation. The removal curves and XPS results indicated that the adsorbed Cr(VI) on the ZIF-8 during the dark process was preferentially reduced. The superior removal efficiency of ZIF-8@TiO₂ is attributed to the combination of both high adsorption of ZIF-8, which attracted Cr(VI) on the composite surface, and the high separation efficiency of photo-induced electron-hole pairs. For the mixture of wastewater that contained methyl orange and Cr(VI), 97.1% of MO and 99.7% of Cr(VI) were removed after 5 min and 60 min light irradiation, respectively. The high removal efficiency of multiple pollutants provides promising applications in the field of Cr(VI) contaminated industrial wastewater treatment. Full article

A current trend within photo-dynamic therapy (PDT) is the development of molecular systems targeting hypoxic tumors. Thus, type I PDT sensitizers could here overcome traditional type II molecular systems that rely on the photo-initiated production of toxic singlet oxygen. Here, we investigate the cell localization properties and toxicity of two polymeric anthracene-based fluorescent probes (neutral Ant-PHEA and cationic Ant-PIm). The cell death and DNA damage of Chinese hamster ovary cancer cells (CHO-K1) were characterized as combining PDT, cell survival studies (MTT-assay), and comet assay. Confocal microscopy was utilized on samples incubated together with either DRAQ5, Lyso Tracker Red, or Mito Tracker Deep Red in order to map the localization of the sensitizer into the nucleus and other cell compartments. While Ant-PHEA did not cause significant damage to the cell, Ant-PIm showed increased cell death upon illumination, at the cost of a significant dark toxicity. Both anthracene chromophores localized in cell compartments of the cytosol. Ant-PIm showed a markedly improved selectivity toward lysosomes and mitochondria, two important biological compartments for the cell’s survival. None of the two anthracene chromophores showed singlet oxygen formation upon excitation in solvents such as deuterium oxide or methanol. Conclusively, the significant photo-induced cell death that could be observed with Ant-PIm suggests a possible type I PDT mechanism rather than the usual type II mechanism. Full article