Core/Shell Nanofibers of Silk Fibroin/Polyvinyl Alcohol: Structure and Controlled Release Behavior

Document Type : Research Paper

Authors

Department of Textile Engineering, Faculty of Engineering, University of Guilan, P.O. Box: 3756, Rasht, Iran

Abstract

Hypothesis: Core-shell nano-fibrous structures obtained from biodegradable and biocompatible polymers such as silk fibroin (SF) have potential applications in drug delivery and tissue engineering. In this work, coaxial electrospinning of silk fibroin as shell and salicylic acid (SA)/polyvinyl alcohol (PVA) blends as core was studied to fabricate core-shell nano-fibrous structures.
Methods: Silk fibroin was extracted from cocoon and dissolved in formic acid. An assembled coaxial nozzle was used to fabricate core-shell nanofibers of SF as shell and PVA/salicylic acid as core components, respectively.
Findings: Effects of variation in viscosity and electrical conductivity of the electrospinning solutions on the final nanofibers morphology, diameters and SA release behaviors were studied using Fourier transforms infrared spectroscopy (FTIR), viscometry, electrical conductometry, ultraviolet spectrophotometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Finally, a suitable model for release behaviors of the fabricated core-shell nanofibers was suggested. It was found that the final diameter of fabricated core-shell nanofibers varied from 110 (±22) to 250 (±71) nm and diameter of the core section varied from 40 to 80 nm. The experimental results showed that the shell solution concentration had a significant effect on the final core-shell nanofiber diameter, but increase in the core solution concentration had an insignificant effect on the final nanofibers diameter. It was concluded that the core solution concentration was not the only effective parameter in determining the final diameters of electrospun nanofibers, and the viscosities of shell and core solutions and their electrical conductivities were just as important parameters. According to the results of release profiles, the ratio of the components in core and shell was the effective parameter affecting the profiles of SA released from these structures. The higher PVA concentration in the core increased both the amount of SA and its release rate from fabricated core-shell nanofibers

Keywords


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