Comparison of Polysaccharides as Coatings for Quercetin-Loaded Liposomes (QLL) and Their Effect as Antioxidants on Radical Scavenging Activity.

Liposomes are microstructures containing lipid and aqueous phases employed in the encapsulation and delivery of bioactive agents. Quercetin-loaded liposomes (QLLs) were coated with three different polysaccharides and then tested as radical scavengers. Lactose (LCQLL), chitosan (CCQLL), and inulin (ICQLL) were employed as coating materials. Particle size determined by light scattering, showed primary size of 200 nm for all samples, while a secondary particle size of 600 nm was observed for CCQLL. Scanning electron microscopy (SEM) evidenced particle aggregation with the addition of the polysaccharide coating. Transmission electron microscopy (TEM) revealed the layered microstructure of liposomes composed of at least two layers, and primary particle size below 100 nm. QLL showed higher antioxidant activity than the coated liposomes. This behavior was attributed to the chemical interaction between quercetin and the corresponding coating polysaccharide in the layered structure, which traps the quercetin and keeps it unavailable for radical scavenging. From the three polysaccharides, lactose showed a better performance as coating material in the antioxidant activity, which suggested that the smaller size of the disaccharide molecule resulted in a faster releasing of the quercetin in the solution. Thus, LCQLL is an advantageous way to deliver quercetin for antioxidant purposes, where the low stability in delivered media of quercetin loaded liposomes is commonly compromised.

Photodegradation of 17 α-methyltestosterone using TiO2 -Gd3+ and TiO2-Sm3+ photocatalysts and simulated solar radiation as an activation source.

According to the search in the state of the art, no antecedents were found in which photocatalytic degradation of 17α-methyltestosterone (MT) hormone has been carried out using doped-TiO2. Nor have the transformation products formed during the heterogeneous photocatalysis (FH) been identified. Therefore, in this study we analyzed the photocatalytic degradation of the MT in aqueous solution, using doped TiO2 with Sm3+ or Gd3+ at 0.3 and 0.5 %wt. Thermal treatment temperature (500 °C and 800 °C) and MT (20 mgL-1) mineralization were also studied. All photocatalysts were synthesized using the sol-gel method and characterized by X-ray Diffraction (XRD), Specific Surface Area (BET), Ultraviolet-visible Spectroscopy (UV-vis), High-Resolution Transmission Electron Microscope/Energy-Dispersive X-ray analysis (HRTEM/EDS) and, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL). MT mineralization was followed by a total organic carbon analyzer (TOC). The route of the photocatalytic mineralization of the hormone was obtained from the analysis of intermediate compounds determined by high performance liquid chromatography coupled to mass spectrometry (LC-TOF-MS). The results showed that TM and its transformation products were not degraded by photolysis. However, the degree of mineralization of the hormone was greater when the photocatalytic process was used. The photocatalytic efficiency was related to the dopant concentration, dopant type and thermal treatment. Therefore, Sm (0.3%)/TiO2 calcined at 500 °C showed the best performance for photocatalytic mineralization of MT.

Synthesis of Carbon Nanotubes of Few Walls Using Aliphatic Alcohols as a Carbon Source.

Carbon nanotubes with single and few walls are highly appreciated for their technological applications, regardless of the limited availability due to their high production cost. In this paper we present an alternative process that can lead to lowering the manufacturing cost of CNTs of only few walls by means of the use of the spray pyrolysis technique. For this purpose, ferrocene is utilized as a catalyst and aliphatic alcohols (methanol, ethanol, propanol or butanol) as the carbon source. The characterization of CNTs was performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The study of the synthesized carbon nanotubes (CNTs) show important differences in the number of layers that constitute the nanotubes, the diameter length, the quantity and the quality as a function of the number of carbons employed in the alcohol. The main interest of this study is to give the basis of an efficient synthesis process to produce CNTs of few walls for applications where small diameter is required.

Cytotoxicity of functionalized carbon nanotubes in J774A macrophages.

Cytotoxicity of carbon nanotubes (CNTs) is a prime concern for its use as antigen carriers. Here we evaluated the cytotoxic effect of unpurified (UP-CNTs), purified (P-CNTs), fluorescein isothiocyanate-functionalized (FITC-CNTs), and Entamoeba histolytica 220-kDa lectin-functionalized CNTs (L220-CNTs) in J774A macrophage (MOs) cell line. Cell viability and apoptosis were analyzed by MTT and TUNEL assays, respectively. Cyclooxygenase-2 (COX-2) was analyzed by reverse transcription-polymerase chain reaction. Cytotoxicity at 6.0 mg/L was higher with UP-CNTs > P-CNTs > FITC-CNTs, showing a decrease in cell viability and an increase in apoptosis. In contrast, MOs interacted with L220-CNTs showed an increase in cell viability without signs of apoptosis. Although UP-CNTs and P-CNTs exhibited COX-2 induction with 6.0 mg/L, functionalized CNTs were able to induce COX-2 at concentrations as low as 0.06 mg/L. These results suggest that functionalization decreases toxicity, and that L220-CNTs may be an excellent candidate for the production of a nanovaccine against amebiasis.