A non-woven fabric wound dressing containing layer - by - layer deposited hyaluronic acid and chitosan.

Novel wound dressings composed of non-woven cotton (NWC) fabric and multilayer of hyaluronan (HA) and chitosan were built using layer-by-layer assembly technique. Factors affecting the building up of that dressings such as HA concentration, number of coating layers and nitrogen content of the NWC fabric quaternized form were studied. Meanwhile, some physico-chemical properties of such dressings were investigated. Moreover, to enhance the antibacterial properties of the aforementioned dressings, Silver nano-particles (Ag NPs) were prepared and incorporated as a functional additive in the final HA layer of such dressings. Factors affecting the building up of that dressings such as HA concentration, number of coating layers and nitrogen content of the NWC fabric quaternized form were studied. The results obtained showed that: i) increasing of HA concentration from 0.25 to 1.0% is accompanied by a gradual reduction in the swelling properties and an improvement in the gel fractionas as well as antibacterial properties of treated fabric along with a decreasing in extents of stiffness, air permeability and the relative water vapor permeability of treated fabric, ii) increasing of steeping time of coated samples results in an improvement in percent swelling of these samples. TEM image of the prepared Ag-NPs depicts that the particle size of that nano-particles was <13nm. Furthermore, the prepared dressing surface was characterized via scanning electron microscope. The EDX of Ag NPs loaded dressings confirmed the presence of Ag NPs onto such dressings with Ag - content of 0.24% (w/w). The thermogravimetric analysis assured that the prepared dressings based on quaternized NWC fabric have higher thermal stability than the un-quaternized form.