Antimicrobial gelatin nanofibers containing silver nanoparticles

Gelatin is one of the most promising biomaterials due to its excellent biocompatibility and biodegradability. In order to improve the antimicrobial activity of gelatin, gelatin nanofibers containing silver nanoparticles were prepared by electrospinning gelatin/AgNO₃/formic acid system, followed by UV irradiation. They were characterized by UV-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analysis. It was observed that the silver nanoparticles, which presented quasi-sphere shaped and 9–20 nm average diameters, were generated on the surface of the gelatin nanofibers. The size of the silver particles can be adjusted by changing the content of AgNO₃. With increasing the amount of AgNO₃, the average diameters of fibers decreased. The gelatin-Ag nanocomposites were found effective against Staphylococcus aureus and Pseudomonas aeruginosa. From these results, it is expected that the electrospun antimicrobial gelatin nanofiber mat can be used as an excellent wound dressing.     

Aroma finishing of PET fabrics with PVAc nanoparticles containing lavender oil

A durable aroma finishing for PET fabric was carried out by adopting poly(vinyl acetate) (PVAc) nanoparticles containing lavender oil (LO) in core. Relatively small size of PVAc nanoparticles (ca. 244 nm of mean particle diameter) was expected to resist the frictional destruction of the particles, which is frequently observed in cases of microcapsules. PVAc nanoparticles containing LO in core were prepared by emulsification-diffusion method and their application as an aroma releasing agent for PET fabrics was assessed through the observation of releasing profiles of LO in ethanol for experimental acceleration. Melamine-formaldehyde (MF) microcapsules containing LO were also prepared and treated on fabrics for comparison. PVAc nanoparticles treated on PET fabric showed higher initial releasing amount, which was ascribed to the enhanced surface area. After 2 days of releasing, PET fabric treated with PVAc nanoparticles showed slower and more stable releasing profile and reached about 12 ppm of cumulative release after 16 days, which was under two thirds of that with MF microcapsules. PVAc nanoparticles can be used as an agent for durable aroma finishing of PET fabrics.     

Investigating the effect of various blend ratios of prepared masterbatch containing Ag/TiO2 nanocomposite on the properties of bioactive continuous filament yarns

In this research, possibility of producing and processing antibacterial organic/inorganic nanocomposite polypropylene filament yarns for permanent antimicrobial efficiency has been investigated. First PP powder and inorganic nanocomposite filler were mixed in a twin screw extruder and modified masterbatch was produced. Continuous filament yarn was made by a pilot plant melt spinning machine from the blend of PP granule and various blending contents of the prepared masterbatch. Pure PP and all other combined samples showed acceptable spinnability at the spinning temperature of 240 °C and take-up speed of 2000 m/min. After producing as-spun filament yarns, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Moreover, the DSC, SEM, FTIR techniques have been used for characterization of samples. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified drawn yarns has reached to 5 %. The observed improvement in the tensile properties of modified as-spun yarns compared to the pure PP was significant. Drawing process improved generally the tensile properties of as-spun yarns. Tensile properties of modified textured and drawn yarns were higher than the pure PP. An optimum of antibacterial activity has been observed in the sample containing 0.75 wt% of nano-filler. It is interesting that the optimum of tensile properties has been also obtained for the sample with maximum bioactivity.     

EGCG纳米粒的制备及其抗肿瘤活性研究

采用热诱导法制备表没食子儿茶素没食子酸酯-抗坏血酸-β-乳球蛋白纳米粒（EGCG-Vc-β-Lg）,考察EGCG与Vc摩尔比对纳米粒粒径、Zeta电位、包埋率、装载量、颜色变化的影响;运用噻唑蓝（MTT）比色法和胞质分裂阻滞微核试验（CBMNT）研究纳米粒对人体黑色素瘤细胞（A-375）、食管癌细胞（TE-1）的增殖抑制作用和初步作用机制。结果表明：EGCG-Vc-β-Lg对A-375、TE-1的增殖抑制有增效作用,并且显著提高了其微核率、凋亡率和坏死率。     

Preparation and properties of 2-(2-aminoethoxy) ethyl chitosan/cellulose fiber using N-methylmorpholine-N-oxide process

N-methylmorpholine-N-oxide (NMMO) is used widely in the manufacturing of man-made cellulose fibers and functional lyocell fibers due to its environment-friendly advantage. Although chitosan is known as a natural antibacterial polymer it has poor solubility in neutral to basic medium and the antibacterial activity is shown only in acidic medium. Chitosan’s poor solubility in NMMO is the disadvantage for the production of antibacterial lyocell fibers. This paper investigates a more “NMMO soluble” derivative of chitosan, 2-(2-aminoethoxy) ethyl chitosan (AECS). AECS has greatly improved solubility in NMMO hydrate, and stronger antibacterial activity than chitosan. AECS was introduced to modify the lyocell fiber spun in a co-solution of cellulose and AECS in NMMO hydrate. The physical properties and antibacterial activity of the fibers were examined and the results indicated that the modified lyocell fiber, containing more than 2 wt% of AECS, exhibits good antibacterial activity against E. coli and slightly decreased tensile strength compared with unmodified fibers.