Nanocomposites composed of polyacrylamide and nanoclay were synthesized via free-radical cross-linking polymerization and used to adsorb Co 2+ and Ni 2+ ions from water. The polyacrylamide (PAM)/sodium montmorillonite (Na-MMT) nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy to confirm the interaction between montmorillonite and the polymer matrix. The effects of pH and heavy metal ion concentration on the adsorption capacity of PAM/Na-MMT were evaluated to determine suitable operating conditions for further experiments. Batch adsorption experimental data were fitted to Langmuir and Freundlich models, which provided information about the adsorption mechanism and the adsorbent surface. The highest Ni 2+ removal yield was found to be 99.3% using the 2:1 (w/w) nanocomposite at pH 6 in 100 ppm of Ni 2+ solution. The Co 2+ removal yield was 98.7% at pH 6 in 60 ppm of Co 2+ solution using the 4:1 (w/w) nanocomposite. These results were higher than those obtained by polyacrylamide and nanoclay under the same conditions (removal yield between 87.40 and 94.50%), indicating that PAM/Na-MMT nanocomposites remove heavy metal water pollutants more efficiently and can be used as a novel adsorbent for further industrial applications.

Camptothecin (CPT) and its analogs exhibit remarkable anti-tumor activity, due to their ability to inhibit DNA topoisomerase I. However, its use is limited by the lack of solubility and stability of the active lactone form. An attractive alternative is the encapsulation of CPT within liposomes. In this study, CPT was incorporated into solid lipid nanoparticles (SLN) based on the triglyceride, Compritol 888 ATO, using supercritical fluid technology without requiring the use of harmful solvents. This drug delivery system was characterized and its cytotoxicity effect was evaluated by measuring MCF7 and MCF10A cell viability as a function of drug loading during a 48-h treatment. Results showed that after 10 h of treatment, MCF7 cells displayed an IC50 of 0.23 AE 0.034 mM at a 1:5 (CPT:SLN) loading and 0.22 AE 0.027 mM at a 1:10 loading, whereas MCF10A cells displayed an IC50 of 0.40 AE 0.036 mM at 1:5 and 0.60 AE 0.063 mM at 1:10. On the other hand, the IC50 of free CPT was 0.57 AE 0.035 mM and 1.07 AE 0.077 mM for MCF7 and MCF10A cells, respectively. Cellular uptake and retention measurements in both cells displayed a two-fold increase when using the SLN formulation. The results from this study showed that the cytotoxic effects of CPT in a SLN formulation improved when compared with those seen with free CPT. The results of this study showed that delivery of CPT as a SLN formulation could be a promising strategy for enhancing its chemotherapeutic effects.

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In this work was studied the effect of sulfonation of styrene-acrylic ester and of titanium dioxide nanoparticles on the proton exchange membranes. It was evaluated the physicochemical characterization of membranes, such as, the water uptake capacity, ion exchange capacity, the mechanic properties of stress/strain, and the chemical functional groups present in the membrane structure by FTIR analysis. Water uptake increases with increasing the time of sulfonation reaction, reaching 60.9% after 8 hours of sulfonation; while, ion exchange capacity of loaded-sulfonated membrane increases with increasing the time of sulfonation reaction and with increasing the TiO 2 load, reaching 0.39 meq/g for 8 hours and 4% TiO 2. It was observed that the elasticity of the synthesized membranes increases with increasing the time of sulfonation reaction, and it decreases with the addition of the TiO 2 load. This physicochemical property set allows to consider the membrane with high potential of application in the fuel cells area.