Effect of silver nanoparticles synthesized by gamma radiation on the cytotoxicity of doxorubicin in human cancer cell lines and experimental animals.

Silver nanoparticles (AgNPs)embedded poly ( N-vinylpyrrolidone/dextran) hydrogels were prepared by gamma radiation. Highly stable and uniformly distributed AgNPs have been obtained within hydrogel networks as nanoreactors via in situ reduction of silver nitrate using sodium borohydride as reducing agent. The formation of AgNPs has been confirmed by Fourier transform infrared spectroscopy. The ultraviolet-visible spectroscopy measurements show a distinct characteristic absorption peaks around 420 nm, indicating the formation of AgNPs. X-ray diffraction analysis and dynamic light scattering demonstrated that the hydrogels have regulated the AgNPs size to a nanoscale. The combination of the AgNPs with doxorubicin (DOX) as a model of antitumor drug forms a new biocompatible nanodrug. Our results show that the AgNPs effectively increased survival rate and decreased tumor volume of Ehrlich ascites carcinoma-bearing mice more than the DOX-treated group and enhanced the cytotoxicity of DOX in different human cancer cell lines (HepG2, T47D, and PC3). DOX-AgNPs decreased malondialdehyde and total nitrate/nitrite levels and increased superoxide dismutase activity and glutathione content in the rat cardiac tissues compared with the DOX-treated group. In conclusion, DOX-AgNPs improved therapeutic index and reduced DOX-induced cardiotoxicity via preservation of cardiac markers, which represents a promising candidate for cancer treatment.

Properties and biocompatibility of polypropylene graft copolymer films.

Modifying the surfaces of polymers has received a great deal of attention, because it could bring about specific surface characteristics such as antithrombogenic property. Therefore, N-vinyl pyrrolidone/sodium acrylate (NVP/Na-AAc) binary monomers were introduced onto polypropylene (PP) films by a radiation grafting method. The effect of solvent and comonomer composition on the degree of grafting was determined. Studies of the mechanical properties and water content of such graft copolymers showed that as the grafting yield increases the elongation percent decreases. However, the water content increases with increasing grafting yield. The blood compatibility of the original PP and PP-g-NVP/Na-AAc films was evaluated by determination of the extent of platelet adsorption and thrombus formation. The blood compatibility of PP-g-NVP/Na-AAc seems to be better than that of original PP.

Use of co-immobilized beta-amylase and pullulanase in reduction of saccharification time of starch and increase in maltose yield.

Beta-amylase and pullulanase were co-immobilized to poly(acrylamide-acrylic acid) resin [P(AAm-AAc)] using 1-ethyl-3-(3-dimethylaminopropyl) carbodimide hydrochloride (EDC). The combined beta-amylase and pullulanase activity was 32% relative to the nonimmobilized beta-amylase. Co-immobilization of beta-amylase and pullulanase increased the maltose yield compared to thart of the immobilized beta-amylase alone and reduced the saccharification time to about 50 h. The results showed that there is a significant increase in the thermal stability, pH stability, and stability toward gamma irradiation. The results also suggest that the co-immobilization of beta-amylase and pullulanase is a potentially useful approach for commercial starch hydrolysis.