Electrosprayed chitin nanofibril/electrospun polyhydroxyalkanoate fiber mesh as functional nonwoven for skin application

Polyhydroxyalkanoates (PHAs) are a family of bio-based polyesters that have found different biomedical applications. Chitin and lignin, byproducts of fishery and plant biomass, show antimicrobial and anti-inflammatory activity on the nanoscale. Due to their polarities, chitin nanofibril (CN) and nanolignin (NL) can be assembled into micro-complexes, which can be loaded with bioactive factors, such as the glycyrrhetinic acid (GA) and CN-NL/GA (CLA) complexes, and can be used to decorate polymer surfaces. This study aims to develop completely bio-based and bioactive meshes intended for wound healing. Poly(3-hydroxybutyrate)/ Poly(3-hydroxyoctanoate-co-3-hydroxydecanoate), P(3HB)/P(3HO-co-3HD) was used to produce films and fiber meshes, to be surface-modified via electrospraying of CN or CLA to reach a uniform distribution. P(3HB)/P(3HO-co-3HD) fibers with desirable size and morphology were successfully prepared and functionalized with CN and CLA using electrospinning and tested in vitro with human keratinocytes. The presence of CN and CLA improved the indirect antimicrobial and anti-inflammatory activity of the electrospun fiber meshes by downregulating the expression of the most important pro-inflammatory cytokines and upregulating human defensin 2 expression. This natural and eco-sustainable mesh is promising in wound healing applications

Silver nanoparticle-coated polyhydroxyalkanoate based electrospun fibers for wound dressing applications

Wound dressings are high performance and high value products which can improve the regeneration of damaged skin. In these products, bioresorption and biocompatibility play a key role. The aim of this study is to provide progress in this area via nanofabrication and antimicrobial natural materials. Polyhydroxyalkanoates (PHAs) are a bio-based family of polymers that possess high biocompatibility and skin regenerative properties. In this study, a blend of poly(3-hydroxybutyrate) (P(3HB)) and poly(3-hydroxyoctanoate-co-3-hydroxy decanoate) (P(3HO-co-3HD)) was electrospun into P(3HB))/P(3HO-co-3HD) nanofibers to obtain materials with a high surface area and good han-dling performance. The nanofibers were then modified with silver nanoparticles (AgNPs) via the dip-coating method. The silver-containing nanofiber meshes showed good cytocompatibility and interesting immunomodulatory properties in vitro, together with the capability of stimulating the human beta defensin 2 and cytokeratin expression in human keratinocytes (HaCaT cells), which makes them promising materials for wound dressing applications

Effects of twisting methods on the plied yarn properties

394-400The influence of twisting method on the properties of Ne 39/1 and Ne 26/1 combed cotton yarns, plied two and three times on ring, two-For-one and balloonless twisting machines, has been studied. The yarn tenacity, breaking extension, work of rupture, twisting variations, hairiness (S3) and hairiness index values of the resultant yarns have been evaluated. The results, evaluated statistically, show that the plying and twisting methods influence the physical properties of plied yarn. The yarns twisted on balloonless twisting machines have lower hairiness and tenacity values than those of the yarns twisted on other machines while the yarns twisted on two-for-one twisting machines attain higher hairiness and twisting variance values than those of the yarns twisted on other machines. In terms of tenacity, the highest improvement obtained after plying occurs in the yarns twisted on two-far-one twisting machines while the lowest improvement is observed in the yarns twisted on balloonless twisting machines. Contrarily, the yarns twisted on ring and balloon less twisting machines show the highest improvement in hairiness and twisting variance values

Cellulose Acetate/ Sodium-Activated Natural Bentonite Clay Nanofibres Produced by Free Surface Electrospinning

Incorporating activated bentonite clay (BC) into electrospun nanofibres is an established strategy for modulating adsorption behaviour. In the present study, naturally occurring calcium BC was completely activated to sodium BC with a 4 wt.% sodium carbonate (Na2CO3)/BC ratio. Composite nanofibre webs were produced from cellulose acetate (CA)/BC spinning solutions using free surface electrospinning and the effect of BC loadings on viscosity, surface tension and electrical conductivity prior to spinning were studied. Chemical and thermal analyses were conducted on as-spun fibres, and SEM and TEM revealed a nanofibrous morphology consisting of an inter-penetrating network of fibres and semi-spherical features resembling jellyfish with an internal core of BC