Multifunctional core–shell electrospun nanofibrous fabrics of poly(vinyl alcohol)/silk sericin (core) and poly(lactide-co-glycolide) (shell)

Core–shell fibres (CSFs) offer a simple route to multifunctional hybrid materials for a wide range of applications. Herein, we report the design of a core–shell electrospun nanofibrous fabric containing a hydrophilic core and hydrophobic shell. CSFs were fabricated for the first time from poly(vinyl alcohol)/silk sericin (from silk cocoons) as the core and poly(lactide-co-glycolide) as the shell. The core serves as a potential carrier for water-soluble bioactive agents, and the shell works as a barrier to prevent premature release of water-soluble agents from the core. The effect of the molecular weight of poly(lactide-co-glycolide) and the loading of silk sericin on the morphology of fibres was studied. The parameters that significantly influence the core–shell electrospinning process were studied to elucidate the most effective conditions to create our multifunctional nanofibrous fabrics with smooth fibre morphology (diameters in the range 800–1300 nm) and low bead formation. Our CSFs were shown to degrade in saline buffer solution (pH 7.4) and were readily rendered with anti-bacterial properties against Staphylococcus aureus and Escherichia coli by the post-spinning deposition of silver nanoparticles (AgNPs, 40 nm diameter) or cinnamon essential oil (CEO). The fibres were non-toxic to normal human dermal fibroblast cell lines, as the cells were shown to attach and proliferate on CSFs, CSF/AgNPs and CSF/CEO with good cell tolerance for 72 h of incubation. These smart multifunctional CSFs show great potential towards smart delivery fabrics/dressings capable of carrying water-soluble bioactive agents surrounded by a protective, but degradable, antibacterial shell to guard the cargo for more effective controlled release.