Development of a Continuous Finishing Chemistry Process for Manufacture of a Phosphorylated Cotton Chronic Wound Dressing

Abstract

A phosphorylated form of cotton gauze for treatment of chronic wounds was designed to improve the wound dressing's capacity to remove harmful proteases from the wound and facilitate healing. Development of the fabric finishing chemistry of the wound dressing with a process suitable for textile mill production required adapting the stationary finishing chemistry of the cotton phosphorylation from a batch-type pad-dry-cure finishing treatment to a continuous pilot scale finishing process. Issues in optimizing the cotton finishing process took into consideration dressing sterilization, the effect of city water versus de-ionized water, retention of the fabric whiteness index and protease sequestration capacity of the dressing, which is the index of the dressing's efficacy. Three types of sterilization approaches were assessed, including gamma ray, ethylene oxide and steam sterilization to determine the effect of sterilization on the phosphorylated cotton dressing and the subsequent efficacy of the sterilized dressing to remove proteases from the wound. Two phosphorylation reagents were compared for their ability to phosphorylate cotton in a urea-based formulation and yield an active, effective dressing, with a high whiteness index. Phosphorylation with a diammonium phosphate (DAP) : urea formulation generally gave a more effective dressing as an active protease sequestrant, and phosphorylation with sodium hexametaphosphate (SMP) : urea gave a higher whiteness index. Finishing formulations combining the Downloaded from two phosphorylating reagents, DAP and SMP : urea, were assessed to improve both whiteness and efficacy. However, sterilization of DAP treated cotton with ethylene oxide eradicated activity through apparent masking of the cellulose phosphate hydroxyls. Side reactions that may occur during ethylene oxide treatment were discussed as the possible origin of the phosphate hydroxyl masking. On the other hand, sterilization with gamma irradiation produced significant yellowing of the dressing. A SMP : urea (16 : 30) formulation was employed in the continuous process finishing treatment, and found to be most optimal for whiteness, efficacy and ease of sterilization, when adapted to industrial scale production of the cotton chronic wound dressing.

Peptide-Cellulose Conjugates on Cotton-Based Materials Have Protease Sensor/Sequestrant Activity

“…Both the physical properties and molecular design of a dressing can conspire to remove proteases from the wound environment either through unintended or a priori design. The molecular features of the material may be targeted to the protease size, charge, active site, or conformation to enhance selective binding of the protein to the dressing material and to trap and remove proteases from the wound bed [ 5 , 13 , 46 , 47 , 48 ]. Negatively charged cellulosic dressings derivatized by phosphorylation, sulfonation, and carboxylation have previously been shown to increase binding to an arginine-rich and positively charged HNE which is also characteristic of all other neutrophil serine proteases [ 13 , 49 ].…”

Hydrogen Peroxide Generation of Copper/Ascorbate Formulations on Cotton: Effect on Antibacterial and Fibroblast Activity for Wound Healing Application

“…Both adsorption and in situ synthesis of copper micro- and nano-particles were performed by way of pad-dry and in-situ nanoparticle synthesis on nonwoven hydroentangled unbleached cotton [ 21 , 22 , 23 ]. The incorporation of copper on the cotton fabrics was quantified and found to range from 3–14 mg/g ( Table 1 ).…”

Cotton‐hydrogel composite for improved wound healing: Synthesize optimization and physicochemical characterization—part 1

“…Cross‐linking is a simple 1‐step procedure in which the substrate meets the monomer, together with a cross‐linking agent. This methodology allows the link of multiple monomers to the substrate mediated by the cross‐linking agent (bifunctional or multifunctional molecules) . The major drawback of cross‐linking is the poor reproducibility due to the arbitrary number and location of linking points and orientation of the monomers …”