A b s t r a c tHuman nerve growth factor β (β-NGF) is considered a major therapeutic agent for treatment of neurodegenerative diseases. We have previously reported the optimized conditions for β-NGF overproduction in Escherichia coli in a shake-flask culture. In this study the optimal %DO (dissolved oxygen) and post induction temperature values for improved production of β-NGF were found in the bioreactor scale using response surface methodology (RSM) as the most common statistical method. Also, for further enhancement of the yield, different post-induction periods of time were selected for testing. In all experiments, the productivity level and bacterial cell growth were evaluated by western blotting technique and monitoring of absorbance at 600 nm, respectively. Our results indicated that %DO, the post-induction time and temperature have significant effects on the production of β-NGF. After 2 hours of induction, the low post induction temperature of 32°C and 20% DO were used to increase the production of β-NGF in a 5-l bioreactor. Another important result obtained in this study was that the improved β-NGF production was not achieved at highest dry cell weigh or highest cell growth. These results are definitely of importance for industrial β-NGF production.K e y w o r d s: bioreactor, RSM, β-NGF over production, E. coli Hajihassan Z. et al.
Bacterial infection is a significant barrier to the natural wound healing process. Silver nanoparticles have antibacterial activity through the destruction of DNA and bacterial membranes. In the present study, a green method was introduced to synthesize silver nanoparticles produced by the Schizophyllum commune. The antibacterial mat loaded with 0.5, 1, and 3% (w/w) of bioactive silver nanoparticles were produced in polyvinyl alcohol (PVA) and schizophyllan (SPG) solution (20:80) with electrospun (PVA/SPG). Then the physicochemical properties of silver nanoparticles and the mats PVA/SPG containing silver nanoparticles were investigated. An animal model also examined antimicrobial activity, cytotoxicity, adhesion, and grade II burn ulcers. The results showed that spherical silver nanoparticles with a diameter of about 40 nm were produced and completely scattered on the nanofibers according to TEM images. A non-covalent interaction was revealed between SPG and AgNPs; the nanofibers were hydrophilic. Nanofibers containing silver nanoparticles had intense antimicrobial activity against E. coli and S. aureus. This inhibition increases with increasing concentration. The cytotoxicity and adhesion results showed that the PVA/SPG-AgNPs 1% sample had the best effect on fibroblast cells. The 1% sample was tested for the animal model, and after 14 days, it had a practical effect on the control. At 14 days post-treatment, a skinny epithelial layer was formed and covered the wound area, and these nanofibers were suitable for wound dressing. Consequently, PVA/SPG-AgNPs nanofibers could be a good option to cover burn wounds by speeding up the wound healing process and treatment costs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.