Fabrication of cellulose fine fiber based membranes embedded with silver nanoparticles via Forcespinning

This study presents the successful development of cellulose fiber based membranes embedded with silver nanoparticles. These fine fiber membranes were developed utilizing the Forcespinning (FS) technique followed by alkaline hydrolysis treatment. The fiber morphology, homogeneity and yield were optimized by varying spinning parameters such as polymer concentration and angular velocity of the spinnerets. The structure, thermal and mechanical properties, and water absorption capability of the developed membranes were investigated. The cellulose acetate (CA) present in the membrane was converted to cellulose in the presence of embedded silver nanoparticles by alkaline hydrolysis. The silver nanoparticles embedded cellulose membrane exhibits outstanding water absorption capacity with fast uptake rate. Its high porosity, three-dimensional network structure with wellinterconnected pores, as well as the intrinsically highly hydrophilic nature of cellulose material greatly favor its potential application as wound dressings. The antimicrobial activity was evaluated by the disk diffusion method. The composite membranes exhibit excellent antimicrobial activity against Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus, owing to the slow and sustained release of embedded silver nanoparticles

Texas Sour Orange Juice Used in Scaffolds for Tissue Engineering

Fine fibers of polyhydroxybutyrate (PHB), a biopolymer, were developed via a centrifugal spinning technique. The developed fibers have an average diameter of 1.8 µm. Texas sour orange juice (SOJ) was applied as a natural antibacterial agent and infiltrated within the fibrous membranes. The antibacterial activity against common Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) was evaluated as well as cell adhesion and viability. The PHB/SOJ scaffolds showed antibacterial activity of up to 152% and 71% against S. aureus and E. coli, respectively. The cell studies revealed a suitable environment for cell growth and cell attachment. The outcome of this study opens up new opportunities for fabrication of fibrous materials for biomedical applications having multifunctional properties while using natural agents

Development of antimicrobial chitosan based nanofiber dressings for wound healing applications

Objective(s): Chitosan based composite fine fibers were successfully produced via a centrifugal spinning technology. This study evaluates the ability of the composites to function as scaffolds for cell growth while maintaining an antibacterial activity. Materials and Methods: Two sets of chitosan fiber composites were prepared, one filled with anti-microbial silver nanoparticles and another one with cinnamaldeyhde. Chitosan powder was dissolved in trifluoroacetic acid and dichloromethane followed by addition of the fillers. The fiber output was optimized by configuring the polymer weight concentration (7, 8, and 9 w/w% chitosan) and applied angular velocity (6000-9000 RPM) within the spinning process. Results: Scanning electron microscopy revealed fiber diameters ranging from 800-1500 nm. Cinnamaldehyde and silver nanoparticles helped to improve and control the anti-bacterial activity. Through a verified cell counting method and disk diffusion method, it was proven that the chitosan based composite fibers possess an enhanced anti-bacterial/microbial activity against gram-positive Staphylococcus aureus. Both composite systems showed anti-bacterial activity, inhibition zones fluctuating between 5 to 10 mm were observed depending on the size of the fiber mat and no bacteria was found within the mats. The developed fiber scaffolds were found to be noncytotoxic serving as effective three-dimensional substrates for cell adhesion and viability. Conclusion: These results provide potential to use these scaffolds in wound healing and tissue regeneration applications

Centrifugally spun PVP/ZnO composite fibers with different surfactants and their use as antibacterial agents

Polyvinylpyrrolidone (PVP) fibers embedded with Zinc Oxide nanoparticles (ZnO NPs) were prepared by the centrifugal spinning of aqueous PVP solutions and ZnO NPs. The ZnO NPs were synthesized and coated with either cetyltrimethylammonium bromide or hexadecyltrimethylammonium bromide. The structure and morphology of the nanocomposite fibers were studied using scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transformed infrared spectroscopy and Thermogravimetric analysis. The effect of surfactant coating on the antibacterial activity of ZnO NPs and PVP/ZnO nanocomposite fibers against Escherichia coli (E. coli) and Bacillus megaterium (B. megaterium) bacteria was systematically investigated. The present study indicated that coating the ZnO NPs with surfactants resulted in large and uniform inhibition of bacterial growth

Antibiotic and Bacteriocin Sensitivity of <i>Listeria monocytogenes</i> Strains Isolated from Different Foods

This study aimed to determine the antibiotic and bacteriocin sensitivity of Listeria monocytogenes strains isolated from animal derived foods. With disc diffusion assay, all fourteen L. monocytogenes strains were suscepti-ble to the antibiotics, including penicillin G, vancomycin, tetracycline, chloramphenicol, rifampicin, erythromycin, gentamicin and trime- thoprim. However, the percentages of fosfomycin and streptomycin resistances were 92.9% and 7.1%, respectively. Multiple resistances were not observed among the tested strains. The results of well diffusion assays showed that all strains were inhibited by the cell-free supernatant of a bacteriocin-producing strain, Pediococcus acidilactici 13, with the inhibition zones ranging from 16.00 to 24.50 mm. These results provide useful information on antibiotic resistance of L. monocytogenes strains isolated from foods, and can potentially be used to develop bacteriocin-based interventions to guard against the hazards associated with L. monocytogenes in ready-to-eat meat and poultry products