Poloxamer-based binary hydrogels for delivering tramadol hydrochloride: sol-gel transition studies, dissolution-release kinetics, in vitro toxicity, and pharmacological evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nanostructured lipid system as a strategy to improve the anti-Candida albicans activity of Astronium sp

The genus Astronium (Anacardiaceae) includes species, such as Astronium fraxinifolium, Astronium graveolens, and Astronium urundeuva, which possess anti-inflammatory, anti-ulcerogenic, healing, and antimicrobial properties. Nanostructured lipid systems are able to potentiate the action of plant extracts, reducing the required dose and side effects and improving antimicrobial activity. This work aims to evaluate a nanostructured lipid system that was developed as a strategy to improve the anti-Candida albicans activity of hydroethanolic extracts of stems and leaves from Astronium sp. The antifungal activity against C. albicans (ATCC 18804) was evaluated in vitro by a microdilution technique. In addition to the in vitro assays, the Astronium sp. that showed the best antifungal activity and selectivity index was submitted to an in vivo assay using a model of vulvovaginal candidiasis infection. In these assays, the extracts were either used alone or were incorporated into the nanostructured lipid system (comprising 10% oil phase, 10% surfactant, and 80% aqueous phase). The results indicated a minimal inhibitory concentration of 125.00 µg/mL before incorporation into the nanostructured system; this activity was even more enhanced when this extract presented a minimal inhibitory concentration of 15.62 µg/mL after its incorporation. In vivo assay dates showed that the nanostructure-incorporated extract of A. urundeuva leaves was more effective than both the unincorporated extract and the antifungal positive control (amphotericin B). These results suggest that this nanostructured lipid system can be used in a strategy to improve the in vitro and in vivo anti-C. albicans activity of hydroethanolic extracts of Astronium sp.

Nanotechnology-based drug delivery systems for the treatment of Alzheimer's disease

Alzheimer's disease is a neurological disorder that results in cognitive and behavioral impairment. Conventional treatment strategies, such as acetylcholinesterase inhibitor drugs, often fail due to their poor solubility, lower bioavailability, and ineffective ability to cross the blood-brain barrier. Nanotechnological treatment methods, which involve the design, characterization, production, and application of nanoscale drug delivery systems, have been employed to optimize therapeutics. These nanotechnologies include polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and liquid crystals. Each of these are promising tools for the delivery of therapeutic devices to the brain via various routes of administration, particularly the intranasal route. The objective of this study is to present a systematic review of nanotechnology-based drug delivery systems for the treatment of Alzheimer's disease.

A curcumin-loaded liquid crystal precursor mucoadhesive system for the treatment of vaginal candidiasis

Women often develop vaginal infections that are caused primarily by organisms of the genus Candida. The current treatments of vaginal candidiasis usually involve azole-based antifungals, though fungal resistance to these compounds has become prevalent. Therefore, much attention has been given to molecules with antifungal properties from natural sources, such as curcumin (CUR). However, CUR has poor solubility in aqueous solvents and poor oral bioavailability. This study attempted to overcome this problem by developing, characterizing, and evaluating the in vitro antifungal action of a CUR-loaded liquid crystal precursor mucoadhesive system (LCPM) for vaginal administration. A low-viscosity LCPM (F) consisting of 40% wt/wt polyoxpropylene-(5)-polyoxyethylene-(20)-cetyl alcohol, 50% wt/wt oleic acid, and 10% wt/wt chitosan dispersion at 0.5% with the addition of 16% poloxamer 407 was developed to take advantage of the lyotropic phase behavior of this formulation. Notably, F could transform into liquid crystal systems when diluted with artificial vaginal mucus at ratios of 1:3 and 1:1 (wt/wt), resulting in the formation of F30 and F100, respectively. Polarized light microscopy and rheological studies revealed that F behaved like an isotropic formulation, whereas F30 and F100 behaved like an anisotropic liquid crystalline system (LCS). Moreover, F30 and F100 presented higher mucoadhesion to porcine vaginal mucosa than F. The analysis of the in vitro activity against Candida albicans revealed that CUR-loaded F was more potent against standard and clinical strains compared with a CUR solution. Therefore, the vaginal administration of CUR-loaded LCPMs represents a promising platform for the treatment of vaginal candidiasis.

Surface modified Mg-doped ZnO QDs for biological imaging

Fundação Amparo à Pesquisa Estado de São Paulo (FAPESP)

Surfactant-based transdermal system for fluconazole skin delivery

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cyto and genotoxicity of gold nanoparticles in human hepatocellular carcinoma and peripheral blood mononuclear cells

Engineered nanomaterials have been extensively applied as active materials for technological applications. Since the impact of these nanomaterials on health and environment remains undefined, research on their possible toxic effects has attracted considerable attention. It is known that in humans, for example, the primary site of gold nanoparticles (AuNps) accumulation is the liver. The latter has motivated research regarding the use of AuNps for cancer therapy, since specific organs can be target upon appropriate functionalization of specific nanoparticles. In this study, we investigate the geno and cytotoxicity of two types of AuNps against human hepatocellular carcinoma cells (HepG2) and peripheral blood mononuclear cells (PBMC) from healthy human volunteers. The cells were incubated in the presence of different concentrations of AuNps capped with either sodium citrate or polyamidoamine dendrimers (PAMAM). Our results suggest that both types of AuNps interact with HepG2 cells and PBMC and may exhibit in vitro geno and cytotoxicity even at very low concentrations. In addition, the PBMC were less sensitive to DNA damage toxicity effects than cancer HepG2 cells upon exposure to AuNps. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Structural, Spectroscopic (NMR, IR, and Raman), and DFT Investigation of the Self-Assembled Nanostructure of Pravastatin-LDH (Layered Double Hydroxides) Systems

Layered double hydroxide (LDH) nanocontainers, suitable as carriers for anionic drugs, were intercalated with Pravastatin drug using magnesium-aluminum and zinc-aluminum in a M-II/Al molar ratio equal 2 and different Al3+/Pravastatin molar ratios. Postsynthesis treatments were used in order to increase the materials crystallinity. Hybrid materials were characterized by a set of physical chemical techniques: chemical elemental analysis, X-ray diffraction (XRD), mass coupled thermal analyses, vibrational infrared and Raman spectroscopies, and solid-state C-13 nuclear magnetic resonance (NMR). Results were interpreted in light of computational density functional theory (DFT) calculations performed for Sodium Pravastatin in order to assign the data obtained for the LDH intercalated materials. XRD peaks of LDH-Pravastatin material and the one-dimensional (1D) electron density map pointed out to a bilayer arrangement of Pravastatin in the interlayer region, where its associated carboxylate and vicinal hydroxyl groups are close to the positive LDH. The structural organization observed for the stacked assembly containing the unsymmetrical and bulky monoanion Pravastatin and LDH seems to be promoted by a self-assembling process, in which local interactions are maximized and chloride ion cointercalation is required. It is observed a high similarity among vibrational and C-13 NMR spectra of Na-Pravastatin and LDH-Pravastatin materials. Those features indicate that the intercalation preserves the drug structural integrity. Spectroscopic techniques corroborate the nature of the guest species and their arrangement between the inorganic layers. Changes related to carboxylate, alcohol, and olefinic moieties are observed in both vibrational Raman and C-13 NMR spectra after the drug intercalation. Thus, Pravastatin ions are forced to be arranged as head to tail through intermolecular hydrogen bonding between adjacent organic species. The thermal decomposition profile of the hybrid samples is distinct of that one observed for Na-Pravastatin salt, however, with no visible increase in the thermal behavior when the organic anion is sequestrated within LDH gap.

Co-nanoencapsulation of magnetic nanoparticles and selol for breast tumor treatment: in vitro evaluation of cytotoxicity and magnetohyperthermia efficacy

Antitumor activities have been described in selol, a hydrophobic mixture of molecules containing selenium in their structure, and also in maghemite magnetic nanoparticles (MNPs). Both selol and MNPs were co-encapsulated within poly(lactic-co-glycolic acid) (PLGA) nanocapsules for therapeutic purposes. The PLGA-nanocapsules loaded with MNPs and selol were labeled MSE-NC and characterized by transmission and scanning electron microscopy, electrophoretic mobility, photon correlation spectroscopy, presenting a monodisperse profile, and positive charge. The antitumor effect of MSE-NC was evaluated using normal (MCF-10A) and neoplastic (4T1 and MCF-7) breast cell lines. Nanocapsules containing only MNPs or selol were used as control. MTT assay showed that the cytotoxicity induced by MSE-NC was dose and time dependent. Normal cells were less affected than tumor cells. Cell death occurred mainly by apoptosis. Further exposure of MSE-NC treated neoplastic breast cells to an alternating magnetic field increased the antitumor effect of MSE-NC. It was concluded that selol-loaded magnetic PLGA-nanocapsules (MSE-NC) represent an effective magnetic material platform to promote magnetohyperthermia and thus a potential system for antitumor therapy.

Application of magnetically induced hyperthermia in the model protozoan Crithidia fasciculata as a potential therapy against parasitic infections

Background: Magnetic hyperthermia is currently a clinical therapy approved in the European Union for treatment of tumor cells, and uses magnetic nanoparticles (MNPs) under time-varying magnetic fields (TVMFs). The same basic principle seems promising against trypanosomatids causing Chagas disease and sleeping sickness, given that the therapeutic drugs available have severe side effects and that there are drug-resistant strains. However, no applications of this strategy against protozoan-induced diseases have been reported so far. In the present study, Crithidia fasciculata, a widely used model for therapeutic strategies against pathogenic trypanosomatids, was targeted with Fe3O4 MNPs in order to provoke cell death remotely using TVMFs. Methods: Iron oxide MNPs with average diameters of approximately 30 nm were synthesized by precipitation of FeSO4 in basic medium. The MNPs were added to C. fasciculata choanomastigotes in the exponential phase and incubated overnight, removing excess MNPs using a DEAE-cellulose resin column. The amount of MNPs uploaded per cell was determined by magnetic measurement. The cells bearing MNPs were submitted to TVMFs using a homemade AC field applicator (f = 249 kHz, H = 13 kA/m), and the temperature variation during the experiments was measured. Scanning electron microscopy was used to assess morphological changes after the TVMF experiments. Cell viability was analyzed using an MTT colorimetric assay and flow cytometry. Results: MNPs were incorporated into the cells, with no noticeable cytotoxicity. When a TVMF was applied to cells bearing MNPs, massive cell death was induced via a nonapoptotic mechanism. No effects were observed by applying TVMF to control cells not loaded with MNPs. No macroscopic rise in temperature was observed in the extracellular medium during the experiments. Conclusion: As a proof of principle, these data indicate that intracellular hyperthermia is a suitable technology to induce death of protozoan parasites bearing MNPs. These findings expand the possibilities for new therapeutic strategies combating parasitic infection.

Synthesis and Physical-Chemical characterization of Metallic Nanoparticles

The stabilization of nanoparticles against their irreversible particle aggregation and oxidation reactions. is a requirement for further advancement in nanoparticle science and technology. For this reason the research aim on this topic focuses on the synthesis of various metal nanoparticles protected with monolayers containing different reactive head groups and functional tail groups. In this work cuprous bromide nanocrystals haave been synthetized with a diameter of about 20 nanometers according to a new sybthetic method adding dropwise ascorbic acid to a water solution of lithium bromide and cupric chloride under continuous stirring and nitrogen flux. Butane thiolate Cu protected nanoparticles have been synthetized according to three different syntesys methods. Their morphologies appear related to the physicochemical conditions during the synthesis and to the dispersing medium used to prepare the sample. Synthesis method II allows to obtain stable nanoparticles of 1-2 nm in size both isolated and forming clusters. Nanoparticle cluster formation was enhanced as water was used as dispersing medium probably due to the idrophobic nature of the butanethiolate layers coating the nanoparticle surface. Synthesis methods I and III lead to large unstable spherical nanoparticles with size ranging between 20 to 50 nm. These nanoparticles appeared in the TEM micrograph with the same morphology independently on the dispersing medium used in the sample preparation. The stability and dimensions of the copper nanoparticles appear inversely related. Using the same methods above described for the butanethiolate protected copper nanoparticles 4-methylbenzenethiol protected copper nanoparticles have been prepared. Diffractometric and spectroscopic data reveal that decomposition processes didn’t occur in both the 4-methylbenzenethiol copper protected nanoparticles precipitates from formic acid and from water in a period of time six month long. Se anticarcinogenic effects by multiple mechanisms have been extensively investigated and documented and Se is defined a genuine nutritional cancer-protecting element and a significant protective effect of Se against major forms of cancer. Furthermore phloroglucinol was found to possess cytoprotective effects against oxidative stress, thanks to reactive oxygen species (ROS) which are associated with cells and tissue damages and are the contributing factors for inflammation, aging, cancer, arteriosclerosis, hypertension and diabetes. The goal of our work has been to set up a new method to synthesize in mild conditions amorphous Se nanopaticles surface capped with phloroglucinol, which is used during synthesis as reducing agent to obtain stable Se nanoparticles in ethanol, performing the synergies offered by the specific anticarcinogenic properties of Se and the antioxiding ones of phloroalucinol. We have synthesized selenium nanoparticles protected by phenolic molecules chemically bonded to their surface. The phenol molecules coating the nanoparticles surfaces form low ordered arrays as can be seen from the wider shape of the absorptions in the FT-IR spectrum with respect to those appearing in that of crystalline phenol. On the other hand, metallic nanoparticles with unique optical properties, facile surface chemistry and appropriate size scale are generating much enthusiasm in nanomedicine. In fact Au nanoparticles has immense potential for both cancer diagnosis and therapy. Especially Au nanoparticles efficiently convert the strongly adsorbed light into localized heat, which can be exploited for the selective laser photothermal therapy of cancer. According to the about, metal nanoparticles-HA nanocrystals composites should have tremendous potential in novel methods for therapy of cancer. 11 mercaptoundecanoic surface protected Au4Ag1 nanoparticles adsorbed on nanometric apathyte crystals we have successfully prepared like an anticancer nanoparticles deliver system utilizing biomimetic hydroxyapatyte nanocrystals as deliver agents. Furthermore natural chrysotile, formed by densely packed bundles of multiwalled hollow nanotubes, is a mineral very suitable for nanowires preparation when their inner nanometer-sized cavity is filled with a proper material. Bundles of chrysotile nanotubes can then behave as host systems, where their large interchannel separation is actually expected to prevent the interaction between individual guest metallic nanoparticles and act as a confining barrier. Chrysotile nanotubes have been filled with molten metals such as Hg, Pb, Sn, semimetals, Bi, Te, Se, and with semiconductor materials such as InSb, CdSe, GaAs, and InP using both high-pressure techniques and metal-organic chemical vapor deposition. Under hydrothermal conditions chrysotile nanocrystals have been synthesized as a single phase and can be utilized as a very suitable for nanowires preparation filling their inner nanometer-sized cavity with metallic nanoparticles. In this research work we have synthesized and characterized Stoichiometric synthetic chrysotile nanotubes have been partially filled with bi and monometallic highly monodispersed nanoparticles with diameters ranging from 1,7 to 5,5 nm depending on the core composition (Au, Au4Ag1, Au1Ag4, Ag). In the case of 4 methylbenzenethiol protected silver nanoparticles, the filling was carried out by convection and capillarity effect at room temperature and pressure using a suitable organic solvent. We have obtained new interesting nanowires constituted of metallic nanoparticles filled in inorganic nanotubes with a inner cavity of 7 nm and an isolating wall with a thick ranging from 7 to 21 nm.

Analytical challenges in the fields of Nanobioscience and Nanobiotecnology: integrated methods for separation and characterization

Nano(bio)science and nano(bio)technology play a growing and tremendous interest both on academic and industrial aspects. They are undergoing rapid developments on many fronts such as genomics, proteomics, system biology, and medical applications. However, the lack of characterization tools for nano(bio)systems is currently considered as a major limiting factor to the final establishment of nano(bio)technologies. Flow Field-Flow Fractionation (FlFFF) is a separation technique that is definitely emerging in the bioanalytical field, and the number of applications on nano(bio)analytes such as high molar-mass proteins and protein complexes, sub-cellular units, viruses, and functionalized nanoparticles is constantly increasing. This can be ascribed to the intrinsic advantages of FlFFF for the separation of nano(bio)analytes. FlFFF is ideally suited to separate particles over a broad size range (1 nm-1 μm) according to their hydrodynamic radius (rh). The fractionation is carried out in an empty channel by a flow stream of a mobile phase of any composition. For these reasons, fractionation is developed without surface interaction of the analyte with packing or gel media, and there is no stationary phase able to induce mechanical or shear stress on nanosized analytes, which are for these reasons kept in their native state. Characterization of nano(bio)analytes is made possible after fractionation by interfacing the FlFFF system with detection techniques for morphological, optical or mass characterization. For instance, FlFFF coupling with multi-angle light scattering (MALS) detection allows for absolute molecular weight and size determination, and mass spectrometry has made FlFFF enter the field of proteomics. Potentialities of FlFFF couplings with multi-detection systems are discussed in the first section of this dissertation. The second and the third sections are dedicated to new methods that have been developed for the analysis and characterization of different samples of interest in the fields of diagnostics, pharmaceutics, and nanomedicine. The second section focuses on biological samples such as protein complexes and protein aggregates. In particular it focuses on FlFFF methods developed to give new insights into: a) chemical composition and morphological features of blood serum lipoprotein classes, b) time-dependent aggregation pattern of the amyloid protein Aβ1-42, and c) aggregation state of antibody therapeutics in their formulation buffers. The third section is dedicated to the analysis and characterization of structured nanoparticles designed for nanomedicine applications. The discussed results indicate that FlFFF with on-line MALS and fluorescence detection (FD) may become the unparallel methodology for the analysis and characterization of new, structured, fluorescent nanomaterials.

Sintesi e caratterizzazione di sistemi nanostrutturati per il trattamento del Glioblastoma multiforme

Nanomedicine is a science based on the preparation of nanosystems for biomedical application. The drugs can be entrapped inside the nanocarriers to improve the drug concentration in the diseased issue through a drug delivery approach; polimeric materials as PLGA-b-PEG has been revealed good properties for this purpose. To improve the nanosystem efficiency it is possible to bind a targeting agent on the carrier surface. In this thesis work silver nanoparticles or drugs as Temsirolimus and Alisertib have been entrapped in PLGA-b-PEG carriers. Chlorotoxin has been linked on the carrier surface as a specific targeting agent for brain tumors. Citotoxicity in vitro of the nanosystems on Glioblastoma cells has been studied.

Nanotechnology control of self organized biomolecules and biomaterials for medical research

Nanotechnology entails the manufacturing and manipulation of matter at length scales ranging from single atoms to micron-sized objects. The ability to address properties on the biologically-relevant nanometer scale has made nanotechnology attractive for Nanomedicine. This is perceived as a great opportunity in healthcare especially in diagnostics, therapeutics and more in general to develop personalized medicine. Nanomedicine has the potential to enable early detection and prevention, and to improve diagnosis, mass screening, treatment and follow-up of many diseases. From the biological standpoint, nanomaterials match the typical size of naturally occurring functional units or components of living organisms and, for this reason, enable more effective interaction with biological systems. Nanomaterials have the potential to influence the functionality and cell fate in the regeneration of organs and tissues. To this aim, nanotechnology provides an arsenal of techniques for intervening, fabricate, and modulate the environment where cells live and function. Unconventional micro- and nano-fabrication techniques allow patterning biomolecules and biocompatible materials down to the level of a few nanometer feature size. Patterning is not simply a deterministic placement of a material; in a more extended acception it allows a controlled fabrication of structures and gradients of different nature. Gradients are emerging as one of the key factors guiding cell adhesion, proliferation, migration and even differentiation in the case of stem cells. The main goal of this thesis has been to devise a nanotechnology-based strategy and tools to spatially and temporally control biologically-relevant phenomena in-vitro which are important in some fields of medical research.

A chemical approach to Heusler compounds and nanoparticles

Heusler Materialien wurden bisher vor allem in Volumen- und Dünnfilmproben aufgrund ihrer technischen Bedeutung untersucht. In dieser Arbeit berichtet über die experimentellen Untersuchungen der chemischen Synthese, Struktur, und der magnetischen Eigenschaften von ternären Heusler-Nanopartikeln. Die grundlegenden Aspekte der Physik, Chemie und Materialwissenschaft bezüglich der Heusler Nanopartiikel wurden untersucht. Außerdem wurde eine silicatgestützte Herstellungsmethode für Karbon-ummantelte, ternäre intermetallische Co2FeGa Nanopartikel entwickelt. Die Bildung der L21 Co2FeGa Phase wurde mit Röntgenbeugung (XRD), Extended X-ray Absorption Fine Structure Spektroskopie (EXAFS), und 57Fe Mössbauer Spektroskopie bestätigt. Die Abhängigkeit der Phase und der der Größe der Co2FeGa Nanopartikel vom der Zusammensetzung der Precursor und des Silicats wurden untersucht. Durch das Koppeln der aus Transmissions-Elektronen-Mikroskopie (TEM) gewonnen Teilchengröße und der Mössbauerspektroskopie konnte die kritische Größe für den Übergang von superparamgnetischem zu ferromagnetischem Verhalten von Co2FeGa Nanopartikel ermittelt werden. Die silicatgestützte chemische Synthese von Co2FeGa Nanopartikeln besitzt großes Potential für eine generelle Herstellungsmethode für Co-basierte Heuser Nanopartikel. Des weiteren wurde auch eine chemische Herstellungsmethode von metallischen Nanopartikeln mit Synchrotronstrahlung untersucht, die so gewonnen Nanopartikel sind vielversprechende Materialien für die Nanobiotechnologie und die Nanomedizin.