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A supramolecular assembly was obtained by combining methylene blue (MB) with a natural plant extract, curcumin (Curc), in a stoichiometric ratio of 1:4 in aqueous solution (90% PBS + 10% ethanol) at room temperature. The MB-Curc supramolecular assembly was evidenced by absorption and fluorescence spectroscopies, and the stoichiometry and bonding constant were obtained using Cieleńs model. Its stability and photostability were evaluated by chromatographic analysis and UV-Vis absorption. The MB-Curc avoids the aggregation of both isolated compounds and efficiently produces singlet oxygen (Φ Δ = 0.52 ± 0.03). Its potential for photodynamic antiangiogenic treatments was evaluated through the vascular effect observed in chicken chorioallantoic membrane (CAM) assay. The results showed intense damage in CAM vascular network by MB-Curc after irradiation, which is higher than the effect of isolated compounds, indicating a synergistic vascular effect. This combination can be essential to prevent cancer revascularization after photodynamic application and improve the efficacy of this approach. The characteristics exhibited by MB-Curc make it a potential candidate for use in cancer treatments through photodynamic antiangiogenic therapy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The present work reports the effects of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS 4 ) aggregation on its excited states absorption spectra, triplet states quenching by molecular oxygen and singlet oxygen production. Experimental techniques such as optical absorption, Z-scan with a white light continuum source and the Laser Flash Photolysis were used to fulfil the study. J-aggregates possess reverse saturable absorption in the 505-660 nm spectral range with a peak centered close to 540 nm. These facts together with their fast relaxation time suggest that they can be employed as material for ultrafast optical limiting and switching. Even though aggregation reduces the porphyrin excited-state lifetimes and quantum yields, it does not reduce the probability of the contact between the quencher and the excited aggregate. Aggregation does not change the contribution of energy transfer mechanisms to triplet state quenching by molecular oxygen. The production of singlet oxygen, the intense absorption in the phototherapeutic window and the high efficiency of conversion of light energy into heat, allow consider J-aggregates as a theranostic agent for photomedicine. It is proposed to use J-aggregates for diagnostics by photoacoustic images and in combination with a near-infrared photodynamic/photothermal dual mode therapy, thus improving synergistically the therapeutic response., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The sesquiterpene nerolidol is a membrane-active compound that has demonstrated antitumor, antibacterial, antifungal and antiparasitic activities. In this study, we used electron paramagnetic resonance (EPR) spectroscopy and biophysical parameters determined via cell culture assays to study the mechanisms underlying the in vitro antileishmanial activity of nerolidol. The EPR spectra of a spin-labeled stearic acid indicated notable interactions of nerolidol with the cell membrane of Leishmania amazonensis amastigotes. The nerolidol IC 50 values in L. amazonensis amastigotes and promastigotes were found to depend on the cell concentration used in the assay. This dependence was described by an equation that considers various cell suspension parameters, such as the 50% inhibitory concentrations of nerolidol in the cell membrane (c m50 ) and the aqueous phase (c w50 ) and the membrane-water partition coefficient of nerolidol (K M/W ). Via cytotoxicity (CC 50 ) and hemolytic potential (HC 50 ) data, these parameters were also determined for nerolidol in macrophages and erythrocytes. With a c w50 of 125 μM, macrophages were less sensitive to nerolidol than amastigotes and promastigotes, which had mean c w50 values of 56 and 74 μM, respectively. The estimated c m50 values of nerolidol for amastigotes and promastigotes and macrophages were between 2.6 and 3.0 M, indicating substantial accumulation of nerolidol in the cell membrane. In addition, the spin-label EPR data indicated that membrane dynamic changes occurred in L. amazonensis amastigotes at concentrations similar to the nerolidol IC 50 value., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Recent research has shown that latex from different species is able to produce tissue replacement and regeneration. Particularly, biomembranes obtained from Hancornia speciosa latex (HSB) have shown high angiogenic and osteogenic activity. Considering new materials for wound healing, it would be interesting to develop a product combining antibacterial and antifungal activities. Silver nanoparticles (AgNP) have been commonly used for this purpose in medicinal products and devices for decades. In order to combine angiogenic, antibacterial and antifungal properties on the same platform, we developed an HSB containing 3 concentrations of AgNP. It was observed that the HSB successfully accommodated the AgNP in the matrix and released them in a controlled way. The release dynamics of AgNP by HSB was described by UV-vis absorption spectroscopy. The released nanoparticles were evaluated by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) measurements. In addition, the cytotoxic and genotoxic effects were evaluated using the Allium cepa assay. The results showed no cytotoxic effect of HSB-AgNP in all studied concentrations. The genotoxic effect was observed in HSB-AgNP at the two highest concentrations, however not at the lowest concentration. Thus, the addition of AgNP at the lowest concentration can improve the pharmacological activity of HSB without causing a toxic effect on vegetal cells. Therefore, the H. speciosa latex biomembrane presented in this paper combines angiogenic, anti-inflammatory and antibacterial properties and can be considered potentially new biomaterial for wound-healing., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Chalcones and their derivatives exhibit numerous pharmacological activities such as antibacterial, antifungal, cytotoxic, antinociceptive and anti-inflammatory. Recently, they have been assessed aiming for novel application in nonlinear optics and in the treatment of immune diseases and cancers. In this study, we investigate the optical properties of synthetic chalcona 1E,4E-1-(4-chlorophenyl)-5-(2,6,6-trimethylcyclohexen-1-yl)penta-1,4-dien-3-one (CAB7β) and its antiangiogenic potential using the chorioallantoic membrane (CAM) with the S180 sarcoma cell line. Experimental and theoretical results show intense absorption in the UVA-UVC region, which is associated with a π → π* transition with intramolecular charge transfer from the trimethyl-cyclohexen-1-yl ring to the chlorophenyl ring. Quantum chemical calculations of the first hyperpolarizability, accounting for both solvent and frequency dispersion effects, are in very good concordance with hyper-Rayleigh scattering measurements. In addition, two-photon absorption allowed band centered at 650 nm was observed. Concerning antiangiogenic activity, CAB7β causes a significant reduction in the total number, junctions, length and caliber of blood vessels stimulated by S180 cells reducing the presence of blood vessels, inflammatory cells and others elements related to angiogenic process. It is found that CAB7β is a versatile compound and a promising candidate for linear and nonlinear optical applications, in therapy against sarcoma and phototherapy., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This work reports on the photophysical properties of zinc porphyrins meso-tetrakis methylpyridiniumyl (Zn(2+)TMPyP) and meso-tetrakis sulfonatophenyl (Zn(2+)TPPS) in homogeneous aqueous solutions and in the presence of sodium dodecyl sulfate (SDS) and cetyltrimethyl ammonium bromide (CTAB) micelles. The excited-state dynamic was investigated with the Z-scan technique, UV-Vis absorption, and fluorescence spectroscopy. Photophysical parameters were obtained by analyzing the experimental data with a conventional five-energy-level diagram. The interaction of the charged side porphyrin groups with oppositely charged surfactants can reduce the electrostatic repulsion between porphyrin molecules leading to aggregation, which affected the porphyrin characteristics such as absorption cross-sections, lifetimes and quantum yields. The interaction between anionic ZnTPPS with cationic CTAB micelles induced the formation of porphyrin J-aggregates, while this effect was not observed in the interaction of ZnTMPyP with SDS micelles. This difference is, probably, due to the difference in electrostatic repulsion between the porphyrin molecules. The insights obtained by these results are important for the understanding of the photophysical behavior of porphyrins, regarding potential applications in pharmacokinetics as encapsulation of photosensitizer for drug delivery systems and in its interaction with cellular membrane., (Copyright © 2013 Elsevier B.V. All rights reserved.)

This work reports on the optical nonlinearities of a newly synthesized pyrazole derivative, namely (E)-1-(4-chlorophenyl)-4-(2-nitrovinyl)-1H-pyrazole. The Z-scan technique with femtosecond laser pulses was used to determine the two-photon absorption (2PA) cross-section spectrum, which presents a maximum of 67 GM at 690 nm. We have combined hyper-Rayleigh scattering (HRS) experiments and second-order Møller-Plesset perturbation theory (MP2) calculations to study the first hyperpolarizability (β(HRS)). It was found that the MP2/6-311+G(d) model, taking into account solvent and dispersion effects, provides the β(HRS) value of 40×10(-30) cm(5)/esu for the compound, in good agreement with the experimental result of 45±2×10(-30) cm(5)/esu., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Porphyrins are an important class of organic molecules, with interesting linear and nonlinear optical properties given mainly by their extended π-conjugation structure. Their photophysical properties can be greatly affected by the surrounding environment, which can be used to tune its final properties. Here we report on an experimental study of the photophysical properties of meso-tetrakis (methylpyridiniumyl) porphyrin (TMPyP) in aqueous and in several organic solvents and its interaction with micelles formed from negatively charged sodium dodecylsulphate (SDS), positively charged cetyl trimethyl ammonium bromide (CTAB) and neutral TRITON X-100. By using the Z-scan technique, flash-photolysis and time-resolved fluorescence techniques, we were able to evaluate the excited state dynamics of the TMPyP, and observed that the tetrapyrrole ring plays important role due to hydrogen bonds formation between nitrogen atom and water, while the side groups determine the porphyrin localization in non-aqueous micelle part., (Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.)