Research is being carried out worldwide on the development of multilayer wound dressing systems with each layer satisfying the requirements of an ideal wound dressing system for achieving better wound healing performance. In this paper, mats were prepared from Eri silk fibroin (ESF) and its blend with poly-L-lactic acid (PLA) polymer by the electrospinning process and evaluated for the properties required for the skin contact layer of wound dressing systems. Tetracycline hydrochloride (TCH) was added to the polymer solution and was spun into a mat. The ESF fibres had a mean diameter of 320 nm and ESF, PLA blend (ESF-PLA) fibres had 502 nm. The phosphate buffer saline (PBS) uptake was less for the ESF-PLA mat compared to that of the 100% ESF mat. The contact angle with water was 23 for the ESF mat and 79 for the ESF-PLA mat. The vapour transmission rate was lower for the ESF-PLA mat compared to that of the 100% ESF mat, however, they were found to be lower than the level at which dehydration would occur. TCH loaded mats showed an effective zone of inhibition against gram positive and gram negative bacteria. A cytotoxicity study on neuroblast cells showed that the ESF mat did not impair the growth of cells. The in vivo study on a rat model showed that the wound healing performance of the mats developed from 100% ESF and ESF-PLA were better compared to the conventional open wound and gauze cloth wound dressing systems.

No abstract

This study reviews the need and importance of non-aqueous dyeing systems in the chemical processing industry, especially using the reverse micellar system in the dyeing of natural fibres. When it comes to conventional dyeing systems, which use large quantities of water, chemical, and energy, cause a lot of effluent load to the environment. Again the effluent water has to be treated well to eliminate all the harmful substances in it. To overcome the issues, a lot of research has been carried out in this area to minimise the use of water and chemicals in the dyeing process. Like use of low material to liquor ratio (M:L) in dyeing, dyes with high fixation at lower temperatures, low/salt less dyeing in case of reactive dyeing with cotton, cottonseed oil dyeing, microwaveassisted dyeing, and use of supercritical carbon dioxide in case of polyester dyeing and many more. All the above said methods are aqueous-based and, after the completion of dyeing, results in wastewater generation, which requires further treatment to reduce the harmful chemicals. Therefore, to further minimise the use of water and chemicals in the dyeing of natural fibres reverse micellar system has been introduced with the help of surfactants of both Ionic and nonionic in nature. As of today, a lot of work has been carried out in the dyeing of natural fibres with this system by employing ionic, nonionic, and mixed surfactants. Fascinating results were obtained in the dyeing with good levelness, high exhaustion, and fixation values, and results were compared with conventional dyeing. Computer colour matching studies were also done better to understand the applicability of these systems in the industry and found nearer results.

No abstract

A nonwoven secondary layer was produced from silk fibroin by a compression and spunlacing method. Super absorbent polymer (SAP) was added to the nonwoven mat to increase the exudates and absorption capacity and manage the moisture in the wound site. Three types of tertiary layers, viz., cotton gauze cloth, adhesive tape, and polyurethane film, were experimented on for the properties that are essential for those layers. The structural stability was found to be better in the spunlaced nonwoven compared to the compressed nonwoven. The Phosphate Buffer Saline (PBS) absorption of the nonwoven increased with an increase in the concentration of SAP percentage. The PBS absorption was found to be lower for the spunlaced nonwoven because of the higher fiber entanglement and packing compared to that of the compressed nonwoven. The vapor permeation rate (grams per square meter a day) across the nonwoven mat decreased with an increase in grams per square meter, and there was no effect from the SAP percentage added to the nonwoven mats. Horizontal and vertical wicking of the spunlaced nonwoven was better than that of the compressed nonwoven. The results showed that spunlaced nonwoven would be a better material for the secondary layer. The vapor transmission rate was highest for cotton gauze cloth, followed by adhesive tape and film. The multilayer wound-dressing system consisting of primary, secondary, and tertiary layers was tested for PBS vapor transmission rate and bacterial penetration. The results showed that the wound-dressing system made from film and adhesive tape did not allow the Staphylococcus aureus bacterial culture to penetrate through the wound-dressing system.