Sulforaphane-assisted preparation of tellurium flower-like nanoparticles.

A new method for the fabrication of flower-like tellurium nanoparticles is reported. It is based on the reduction of tellurite precursor by products generated during decomposition of sulforaphane at elevated temperature in aqueous medium. These species and other organic molecules present in the reaction mixture are being adsorbed on the surface of tellurium nuclei and govern further tellurium growth in the form of nanoflowers. The obtained particles have been characterized by a range of physicochemical techniques. It was shown that the average size of the nanoflower particles is ca. 112 nm, and they are composed of smaller domains which are ca. 30 nm in diameter. The domains are crystalline and consist of trigonal tellurium as shown by x-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. The tellurium nanoflowers were examined from the perspective of their potential anticancer activity. The in vitro cell viability studies were conducted on breast cancer (MDA-MB-231, MCF-7) and normal cell lines (MCF-10A) employing MTT and CVS assays. It was shown, that the nanoflowers exhibit considerable cytotoxicity against cancer cells which is ca. 3-7 times higher than that observed for reference normal cells. The preliminary in vivo investigations on rats revealed that the nanoflowers accumulate predominantly in pancreas after intraperitoneal administration, without observable negative behavioral effects.

Sulforaphane-conjugated selenium nanoparticles: towards a synergistic anticancer effect.

Sulforaphane-modified selenium nanoparticles can be prepared in a simple aqueous-phase redox reaction through reduction of selenite with ascorbic acid. The sulforaphane molecules present in the reaction mixture adsorb on the nanoparticle surface, forming an adlayer. The resulting conjugate was examined with several physicochemical techniques, including microscopy, spectroscopy, x-ray diffraction, dynamic light scattering and zeta potential measurements. As shown in in vivo investigations on rats, the nanomaterial administered intraperitoneally is eliminated mainly in urine (and, to a lesser extent, in feces); however, it is also retained in the body. The modified nanoparticles mainly accumulate in the liver, but the basic parameters of blood and urine remain within normal limits. The sulforaphane-conjugated nanoparticles reveal considerable anticancer action, as demonstrated on several cancer cell cultures in vitro. This finding is due to the synergistic effect of elemental selenium and sulforaphane molecules assembled in one nanostructure (conjugate). On the other hand, the cytotoxic action on normal cells is relatively low. The high antitumor activity and selectivity of the conjugate with respect to diseased and healthy cells is extremely promising from the point of view of cancer treatment.

Combined effects of agrochemical contamination and forest loss on anuran diversity in agroecosystems of east-central Argentina.

Agricultural expansion and intensification has led globally to a rapid landscape structure change and high agrochemical use resulting in habitat loss and degraded environmental quality. Co-occurrence of landscape change and agrochemical contamination threatens biodiversity and might have interactive effects especially for organisms with complex life-cycles such as amphibians. We evaluated effects of landscape structure and agrochemical contamination at different spatial scales on anurans in Entre Rios, Argentina. We selected 35 independent stream headwaters along an agricultural expansion and intensification gradient. We conducted anuran call surveys from spring 2012 to summer 2013 and obtained detection-non detection data to estimate mean richness and focal species occupancy. We quantified forest area and riparian forest width at two spatial scales (sub-basin and local reach scale). We measured nutrients and pesticides in water and sediment. We evaluated anuran response to landscape and contamination variables using GLMs for richness and single season single-species occupancy models for focal species. Anuran diversity increased with forest area and riparian forest width, and decreased at sites with herbicide and nutrient contamination, particularly glyphosate; 2,4-D and nitrates. Also, most focal frog species responded mainly to basin forest and 2,4-D. Negative effects of agrochemical contamination on anuran diversity was mitigated in areas with larger basin forest cover. Agricultural management should ensure the reduction of herbicide and fertilizer use, the sparing of adequate forested habitat within drainage areas, and preservation of riparian forests around anuran breeding habitat to reduce and mitigate the negative effects of agrochemical contamination on anurans diversity in agroecosystems.

In the triple-negative breast cancer MDA-MB-231 cell line, sulforaphane enhances the intracellular accumulation and anticancer action of doxorubicin encapsulated in liposomes.

A new combination of sulforaphane (a natural compound obtained from Brassicaceae vegetables) and the cytostatic drug doxorubicin was entrapped in nanometer-sized liposomes. In vitro experiments were performed to investigate the cytotoxicity of these structures on the human breast cancer cell line MDA-MB-231. Confocal microscopy studies revealed enhanced cellular endocytotic internalization, followed by the release of the examined combination from the lysosomes. The in vitro interaction analysis using the Chou-Talalay approach showed high synergistic activity of the examined combination. This synergistic activity enables a considerable reduction in cytostatic dosage and an increase in cancer treatment efficiency.

Nano-radiogold-decorated composite bioparticles.

Hybrid composite bioparticles modified with stable and radioactive gold nanoparticles were prepared via reduction of tetrachloroauric acid within Lactobacillus rhamnosus cells. The resulting biocomposite material was characterized using a number of physicochemical techniques, including microscopic, spectroscopic and thermal methods. The bacterial particles act as a type of template for gold deposition. Gold nanoparticles of approximately 3.7 nm diameter are formed and are uniformly distributed within the bacterial cell, including its hydrogel outer shell. For radioactive gold-198, the ß- radiation emitted from the biocomposite particles can be used for therapeutic purposes, as demonstrated in vitro in cancer cell cultures. The antitumor activity can be further enhanced by incorporation of doxorubicin, a cytostatic drug, within composite particles. The cell viability data indicate the considerable synergistic effect of ß- radiation and doxorubicin on breast cancer cells (MCF-7). The antitumor action of the biocomposite particles is very promising for new anticancer therapies.

Magnetic polymer microcapsules loaded with Nile Red fluorescent dye.

Fabrication of multifunctional smart vehicles for drug delivery is a fascinating challenge of multidisciplinary research at the crossroads of materials science, physics and biology. We demonstrate a prototypical microcapsule system that is capable of encapsulating hydrophobic molecules and at the same time reveals magnetic properties. The microcapsules are prepared using a templated synthesis approach where the molecules to be encapsulated (Nile Red) are present in the organic droplets that are suspended in the polymerization solution which also contains magnetic nanoparticles. The polymer (polypyrrole) grows on the surface of organic droplets encapsulating the fluorescent dye in the core of the formed microcapsule which incorporates the nanoparticles into its wall. For characterization of the resulting structures a range of complementary physicochemical methodology is used including optical and electron microscopy, magnetometry, 1H NMR and spectroscopy in the visible and X-ray spectral ranges. Moreover, the microcapsules have been examined in biological environment in in vitro and in vivo studies.

Incorporation of pyrene in polypyrrole/polystyrene magnetic beads.

Pyrene, a fluorescent dye, was incorporated into polystyrene particles coated with polypyrrole. The incorporation was achieved by treating the polypyrrole/polystyrene (PPy/PS) beads in a tetrahydrofuran (THF) solution of the pyrene fluorophore followed by rinsing with methanol. The polystyrene cores of the beads swell in THF, allowing penetration of pyrene molecules into the polystyrene structure. The addition of methanol causes contraction of the swollen polystyrene, which encapsulates the dye molecules inside the beads. It is shown that the polypyrrole coating is permeable with respect to both the dye and the solvent, allowing the transport of molecules between the polystyrene cores and the contacting solution. The polypyrrole adlayer can be used as a matrix for the incorporation of magnetic nanoparticles. Embedded particles provide magnetic functionality to the PPy/PS beads. It is demonstrated that the pyrene-loaded beads can be manipulated with an external magnetic field.