| dc.description.abstract | Electrospinning is a simple, inexpensive, and practical way to produce fibers and particles at the micro- and nano-scale. In this method, nanofibers are produced by applying an electric current to the polymeric solution. The fibers produced by this method have high surface-to-volume ratios and porosity, which are used in various fields of medicine, drug delivery system and food industry. The aim of this study was to evaluate the spinning potential of chitosan and gellan gum solution at different ratios and concentrations considering their physicochemical changes. In this study, chitosan and gellan gum were first used for nanofibers production. The nanofibers were used to load resveratrol, and the release process and properties of resveratrol during in vitro colonization were investigated.
Material and method
First, the spinning ability of chitosan solution in acetic acid and trifluoroacetic acid solvents was investigated. Then the effect of adding gellan gum to the solution was evaluated. The nanofibers were produced from the chitosan and gellan gum solution by determining the optimum parameters in electrospinning (polymer solution parameters: viscosity, electrical conductivity, surface tension and device parameters: voltage, needle to plate retraction, soluble flow rate). The shape and size of the nanofibers were observed and measured using the scanning electron microscope. The best formulations were selected for further experiments in terms of morphology and size of nanofibers. The viscosity, surface tension and electrical conductivity of the solutions were measured. Chemical interactions were investigated using the Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Resveratrol was loaded in nanofibers then encapsulation efficiency of nanofibers were measured. Release property of resveratrol from nanofibers in acidic and natural medium were experimented. The antioxidant activity of resveratrol and its cytotoxicity on colon cancer cells were tested.
Result
Chitosan solution was spinable in acetic acid and trifluoroacetic acid solvents. However, the fibers produced in trifluoroacetic acid were uniform and without the capsule form. By increasing the chitosan concentration from 3% to 9% the shape of fibers was uniform and without the capsule form. The best ratio of chitosan to gellan was obtained at 95: 5, respectively. At higher ratios, the viscosity of the mixture increased greatly and disrupted the electrospinning process so that the solubility in the 60:40 ratio was not spinable. The optimum conditions were obtained for 25 kV voltage, 8 cm needle distance and 0.4 ml / h flow rate. The best structure was used for loading resveratrol, which had a loading efficiency of 86% (95:5). The rate of resveratrol release in chitosan-gellan fibers under acidic conditions was lower than that of chitosan fibers alone. This is due to the greater resistance of the gel to acidic conditions. The FTIR spectra of chitosan-gellan and resveratrol nanofibers showed that different functional groups interacted with chitosan and gellan gum and resveratrol solutions. The thermal stability of the nanofibers was also investigated and all materials were shown to be degraded at 600 °C.
Conclusion
The chitosan-gel solution was successfully electrospun and used as a suitable structure for resveratrol encapsulation. This technique is introduced as a convenient and effective method of delivery of the drug to the colon. | en_US |
