Synthesis and study of a new biopolymer-based chitosan/hematoxylin grafted to cotton wound dressings

The present paper describes the development of wound dressing with high-enhanced biological characteristics. Firstly, we have synthesized a new polymer-based chitosan/hematoxylin (poly-PAA-CZ-HX), a bioactive blend for combined antibacterial and tissue regeneration properties. The main aim was to functionalize the wound dressing biomaterial with this bioactive medical polymer via a chemical grafting process. This functionalization must offer a permanent graft and preserve the medical properties of the added polymer of chitosan/hematoxylin. We have then studied the influence of different parameters involved in this particular grafting processing. Main parameters included thermofixation conditions (time and temperature) in addition to the concentration of different reactants. The last mentioned consist of a crosslinking agent the polyacrylic acid (PAA), a selected catalyst the sodium dihydrogen hypophosphite (NaH2PO2), and thepoly-PAA-CZ-HX. Sorption capacity of modified dressings was then evaluated via the technique of the contact angle at various grafting rates. These wettability measurements have revealed a significant decrease of the contact angle of samples after functionalization, a desired characteristic of wound dressings, which means the clear improvement of the hydrophilicity. After the untreated and grafted cotton dressings were characterized by ATR-IR spectroscopy and TGA/DTA analysis, the results showed a chemical permanent grafting that resisted to standardized washings. Then an evaluation of mechanical properties of cotton dressings grafted with various proportions of poly-PAA-CZ-HX polymer was accomplished. Results revealed that the grafting reaction with selected conditions did not damage the mechanical characteristics of our native wound dressings. Finally, a SEM morphological study confirmed the permanent graft of the crosslinked CZ/HX biopolymer grafted to the cotton fibers and allowed us to evaluate its chemical grafting mode onto functionalized surfaces. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47625.