Preparation and evaluation of physicochemical properties of novel alkaline calcium alginate hydrogels with carbonated water

Hydrogels are highly biocompatible materials, and alginate is utilized for wound dressing. Contrary to traditional beliefs, alkaline conditions (ie, pH of approximately 8.5) are favorable for healing wounds. However, existing wound dressing materials are employed under neutral or weakly acidic (pH 5.5-6.5) conditions. To address this issue, in this study, we successfully prepared alkaline calcium alginate hydrogels using carbonic acid and evaluated their physicochemical properties. Using inversion tube tests, we determined that the gelation time of the hydrogels was less than 5 minutes. Furthermore, the pH measurements demonstrated that the prepared gels were alkaline (pH of 8.38-8.57) due to the volatilization of carbon dioxide from the hydrogel surface. Due to the short gelation time of the hydrogels, they can be prepared immediately before use under medical settings, and the pH of the hydrogels may facilitate the proliferation of fibroblasts and keratinocytes. In addition, the physicochemical properties of the prepared hydrogels were determined to be excellent with respect to transparency, the ability to absorb physiological saline, and possessing a high water content (approximately 99%). The hydrogel prepared in this study may have applications in wound dressings.