Curcumin antifungal and antioxidant activities are increased in the presence of ascorbic acid

The objective of this study was to evaluate the antifungal and antioxidant activities of curcumin, ascorbic acid and the mixture of these two compounds. For the antifungal assay, the minimum inhibitory concentrations (MIC) were determined using Candida strains (ATCC and clinical isolates). Curcumin alone inhibited growth of Candida albicans yeast cells, whereas ascorbic acid did not present effects. However, when the mixture of ascorbic acid and curcumin was assayed to determine the association of the two compounds, the curcumin MIC decreased 5- to 10-fold. In the antioxidant assays, the sum of the alone activities of curcumin and ascorbic acid were lower than the activity of the two-compound mixture. This study highlights the importance of the association between two common antioxidants in foods, to improve the antifungal and antioxidant activities of curcumin (in vitro), and can be applied to Candida spp. infection and diseases associated with oxidative stress.     

Properties of p- and n-Type PbTe Microwires for Thermoelectric Devices

In thermopower measurements, microwires fabricated from as-purchased bulk PbTe exhibits p-type behavior between room temperature and ～600 K. At higher temperatures, it undergoes majority carrier inversion and exhibits n-type behavior. We report on the preparation and properties of potassium oxide and Zn-doped PbTe microwires, which exhibit stable p- and n-type behavior, respectively, between room temperature and 725 K. Thermoelectric figures of merit (ZT) are reported for device components prepared from bundles of such p- and n-type microwires in a glass matrix.     

Single and mixed poloxamine micelles as nanocarriers for solubilization and sustained release of ethoxzolamide for topical glaucoma therapy

Polymeric micelles of single and mixed poloxamines (Tetronic) were evaluated regarding their ability to host the antiglaucoma agent ethoxzolamide (ETOX) for topical ocular application. Three highly hydrophilic varieties of poloxamine (T908, T1107 and T1307) and a medium hydrophilic variety (T904), possessing a similar number of propylene oxide units but different contents in ethylene oxide, were chosen for the study. The critical micellar concentration and the cloud point of mixed micelles in 0.9 per cent NaCl were slightly greater than the values predicted from the additive rule, suggesting that the co-micellization is hindered. Micellar size ranged between 17 and 120 nm and it was not altered after the loading of ETOX (2.7–11.5 mg drug g^–1 poloxamine). Drug solubilization ability ranked in the order: T904 (50-fold increase in the apparent solubility) > T1107 ≅ T1307 > T908. Mixed micelles showed an intermediate capability to host ETOX but a greater physical stability, maintaining almost 100 per cent drug solubilized after 28 days. Furthermore, the different structural features of poloxamines and their combination in mixed micelles enabled the tuning of drug release profiles, sustaining the release in the 1–5 days range. These findings together with promising hen''s egg test-chorioallantoic membrane biocompatibility tests make poloxamine micelles promising nanocarriers for carbonic anhydrase inhibitors in the treatment of glaucoma.     

Silica Nanoparticles Containing Gadolinium Complex as Potential Alternative to Anticancer Radiotherapy

Today, cancer represents one of the main causes of death worldwide, making it a formidable challenge for all scientific areas that seek new therapeutic approaches for its cure. As a therapeutic approach, radiotherapy, widely used in treating various types of tumors, acts by not discriminating healthy cells from tumor cells. Seeking to minimize these effects, nanostructured carriers of radioisotopes have been studied with the aim of improving the specificity of action of ionizing radiation, delivering and retaining adequate amounts of radioactive isotopes within tumor cells, leading them to death. In the present work, silica nanoparticles were prepared in order to evaluate their capacity to act as a nanocarrier of the ¹⁵⁹Gd-DTPA-BMA radioactive complex, which can selectively deliver high radiation doses to tumors. Furthermore, this formulation seeks to prevent nontarget tissues from receiving excessive amounts of radiation, acting as a new potential alternative to conventional radiotherapy, in which a large dose of radiation is delivered to nontarget tissues, causing harm to healthy surrounding tissues.     

Effect of diode-laser and AC magnetic field of bovine serum albumin nanospheres loaded with phthalocyanine and magnetic particles

This study reports on the development and characterization of bovine serum albumin (BSA) nanospheres containing Silicon(IV) phthalocyanine (NzPc) and/or maghemite nanoparticles (MNP), the latter introduced via ionic magnetic fluid (MF). The nanosized BSA-loaded samples were designed for synergic application while combining Photodynamic Therapy and Hyperthermia. Incorporation of MNP in the albumin-based template, allowing full control of the magnetic content, was accomplished by adding a highly-stable ionic magnetic fluid sample to the albumin suspension, following heat denaturing. The material's evaluation was performed using Zeta potential measurements and scanning electron microscopy. The samples were characterized by steady-state techniques and time-resolved fluorescence. The in vitro assay, using human fibroblasts, revealed no cytotoxic effect in all samples investigated, demonstrating the potential of the tested system as a synergistic drug delivery system.     

Photophysical and complexation studies of chloro-aluminum phthalocyanine with beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin

A variety of nanostructures are being investigated as functional drug carriers for treatment of a wide range of diseases, most notably cardiovascular defects, autoimmune diseases, and cancer. The aim of this present contribution is to evaluate potentially applicable nanomaterials in the diagnosis and treatment of cancer due to their photophysical and photobiological properties and complexation behavior. The delivery systems consisted of chloro-aluminum phthalocyanine associated with beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin. The preparation of the complex and its stoichiometry in an ethanol/buffer (3:1) solution were studied by spectroscopic techniques, which were defined as 1:2. The inclusion complex in the nanometer scale was observed on the basis of changes to the spectroscopic properties. The singlet oxygen production and complex photophysical parameters were determined by measuring luminescence at 1270 nm and by steady state and time resolved spectroscopic, respectively. The preparation of the complex was tested and analyzed with regard to cellular damage by visible light activation. The inclusion complex showed a higher singlet oxygen quantum yield compared with other systems and other photoactive dyes. There was also a reduction in the fluorescence quantum yield compared with the results obtained for zinc phthalocyanine in organic medium. The results reported clearly that the inclusion complex chloro-aluminum phthalocyanine/cyclodextrin showed some changes in its spectroscopy properties leading to better biodistribution and biocompatibility with a potential application in photodynamic therapy, especially in the case of neoplasy. Additionally, it also has non-oncological applications as a drug delivery system.     

Photophysical and photobiological studies of a silicon tribenzonaphthoporphyrazinato incorporated into liposomes for photodynamic therapy use

Nanostructured drug delivery systems (NDDS), such as liposomes, represent a growing area in biomedical research. These microheterogeneous media can be used in many biological systems to provide appropriate drug levels with a specific biodistribution. The photophysical properties of a silicon derivative of tribenzonaphthoporphyrazinato (Si-tri-PcNc) incorporated into liposome were studied by steady-state techniques, time-resolved fluorescence and laser flash photolysis. All the spectroscopy measurements performed allowed us to conclude that Si-tri-PcNc in liposome is a promising NDDS for PDT. The in vitro experiments with liposomal NDDS showed that the system is not cytotoxic in darkness, but exhibits a substantial phototoxicity at 1 microM of photosensitizer concentration and 10.0 J/cm2 of light. These conditions are sufficient to kill about 80% of the cells.