Fabrication and characterization of gas-assisted core-shell hydrogel nanofibers as a drug release system with antibacterial activity

• Gas-assisted coaxial electrospinning for fabrication of core-shell hydrogel nanofibers. • Loading of Sage extract into PLA nanofibers in the core and evaluation of the release process. • Production of a hydrogel shell with various amounts of the crosslinking agent and investigation of the swelling kinetics. • The effect of the different concentrations of the crosslinking agent on the swelling kinetics and release rate in core–shell nanofibers. • The antibacterial properties of the Sage extract-loaded nanofibers were studied. In this research, fabrication and characterization of core-shell hydrogel nanofibrous mats containing Polylactic acid/Sage extract in the core and Polyvinylpyrrolidone/Polyvinyl alcohol in the shell, utilizing a novel gas-assisted coaxial electrospinning technique was investigated. The use of an extra gas blowing system allowed to increase core and shell flow rates remarkably and contributed to the higher production of nanofibers in a very short time. To construct the core-shell structure, first, the core solution containing Polylactic acid 8 wt% and Sage extract 10 wt% was prepared. Then the shell solution including Polyvinylpyrrolidone 20 wt% and Polyvinyl alcohol 9 wt% was made and citric acid 2.5 wt% was added as the crosslinking agent. The core and shell solutions were loaded separately in a coaxial spinneret and the gas-assisted coaxial electrospinning was conducted. In the end, the electrospun mats were cured in an oven to obtain core-shell hydrogel nanofibers. The kinetics of the swelling, the release of Sage extract, and the effects of various amounts of crosslinker on the swelling and release process were investigated for core-shell hydrogel nanofibers and then compared to that of the single-core and shell systems. Moreover, the antibacterial assay was performed on the fabricated core-shell hydrogel nanofibers to assess the antimicrobial properties of the electrospun mats. Further evaluations were performed through SEM, TEM, FTIR, DSC, and TGA analyses to determine the morphology and structure of individual systems. The electrospun mats can find excessive applications in biomedical fields as antibacterial dressings for superficial wounds.