Alginate fibers are well established as primary wound dressings, given their well-known sodium/calcium ion exchange ability at the wound surface coupled with their good liquid absorption characteristics. Chitosan, the deacetylated form of chitin is also well known for its hemostatic, antimicrobial, and wound-healing properties. Unique combination of these polysaccharides to form a new generic fiber, known as alchite fibers, has been developed in an earlier work. This article reports on the antimicrobial properties of a range of alchite fibers produced from four different types of hydrolyzed chitosans and two brands of sodium alginate. The article discusses different methods of antimicrobial detection including: submerged fiber technique, zone of inhibition, dilution plating, and spectrophotometric analysis at 600 nm when tested against common skin microflora, i.e., Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus. This study concludes that while most of the alchite fiber samples have certain degree of antimicrobial properties, some have higher antimicrobial properties than others. The study has also shown that quantitative presence of chitosan within an alchite fiber may not necessarily be the reason for good antimicrobial properties. Factors such as chitosan source, degree of deacetylation, molecular weight, and action of hydrolysis may also affect antimicrobial properties. These findings are most important in endorsing the development of the alchite fibers for wound dressings.

Electrospinning generates nanofibres at speeds that often surpass those of conventional man-made fibre production. This makes control and manipulation of these nanofibres that much more difficult and challenging. However, to take full advantage of the superior properties of electrospun nanofibres, their production process must be clearly understood and all possible means of fibre formation and hence fibre control explored. This article attempts to explain electrospun fibre production from first principles and uses schematics to follow the electrospinning process from inception, i.e. in the nozzle, to collection with respect to electrostatic behaviours. The complex interrelationship between the charged species in the moving solution and their subsequent polarization and the induced internal field by the applied external electric field are systematically explored and explained.

Objective: This laboratory-based study set out to establish whether branan ferulate — a polysaccharide compound available in gels such as as Sterigel (SSL International, UK) — could be successfully added to the fibre of an alginate dressing to provide a superior wound-care dressing. Method: A wet extruder (Howden Engineering Services, UK) was used to produce the fibres. Researchers examined the effect of spinning-bath calcium chloride concentration (used as the coagulant in the fibre-spinning process) on the tensile and absorption properties of alginate fibres containing 25% w/w branan ferulate. Sodium alginate and branan ferulate were separately dissolved in de-ionised water and then stirred together to make up a 5% dope solution. The dope was then forced through a spinneret and into the calcium chloride bath, where fibres were precipitated and then carried over the first set of rollers. The fibres were washed in the next bath and drawn at different rates to enhance their tensile properties. At the ‘winding-up’ stage the filaments were either passed over a contact heater and into a furnace (dry pick-up) or transferred into acetone baths of increasing concentrations of 50, 80 and 100% aqueous acetate to remove the water (wet pick-up). The moisture content of standard alginate fibres and those with branan ferulate were measured and compared. Breaking load, tenacity and breaking extension, and the quantity of branan ferulate in the fibres were also measured. The process was repeated four times, using different strengths of calcium chloride. Using various draw ratios, the effects of liquid uptake were measured using water, saline and a solution called A (to mimic human blood and exudate-type fluids). Results: Out of the four calcium chloride concentrations used, 1% concentration appeared to give the highest and most conclusive results for fibre-breaking load, tenacity and breaking extension. Conclusion: A 1% w/v concentration of calcium chloride provides the optimum conditions for achieving suitably strong fibres with adequate absorption capacity, while allowing the least branan ferulate loss during wash and post-production treatments. In a laboratory setting the product showed promise. Research is now needed in a clinical setting and for comparison with existing wound-care products. Declaration of interest: This study was funded and sponsored by SSL International, Oldham, UK.

Carpet waste has successfully been converted into acoustic underlay materials that compete with commercial counterparts both in terms of performance and costs. This paper builds on an earlier paper [Miraftab et al, Autex Res.J.5(2), 96-105 (2005).] where granular/fibre mixing ratios, binder concentration and particle size distribution were shown to play a major role in maximising impact sound insulation capabilities of developed underlays. Product optimisation with respect to the particle size as governed by the aperture dimension and mean effective fibre length is further explored in this paper, and the developed underlay is compared with a selection of commercially available acoustic underlays. The results show that a 2mm-aperture screen at the granulating chamber output yields a waste stream with grains in the size range of 0.5-1.0mm and a mean effective fibre length of 2.75 mm which was most suitable to work with, and gave rise to samples with the best impact sound reduction performance. The optimised sample of 10mm recycled underlay (U2) appeared to perform better than most commercial systems tested. The manufactured underlay withstood, and in some instances, outperformed, during the standard tests as required within the BS 5808 protocol. The study concludes that recycling carpet waste to produce quality acoustic underlay with desirable impact sound insulation characteristics is technically feasible, and a viable alternative to landfill or incineration.