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

Abstract

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.

Physicochemical Properties of Egg-Box-Mediated Hydrogels with Transiently Decreased pH Employing Carbonated Water

“…Interestingly, Pec-Ca-CW is more alkaline than Pec-Ca, although the initial pH of the former is lower (Figure ). This difference was not observed in the previous study on alginate/CaCO 3 hydrogels because alginate/CaCO 3 could not be transformed into a hydrogel without carbonated water. Pec-Ca-CW can have a higher cross-linking structure, as shown in Figure c.…”

“…In this study, LM pectin hydrogels were prepared using carbonated water to investigate the influence of adding CO 2 as the acidic agent (Figure a). We have developed a method using carbonated water to supply carbonate ions and CO 2 to a gelation mixture; this triggered the gelation of the mixed alginate/CaCO 3 solution under ambient pressure and temperature without requiring precise pressure and temperature controls. , Unlike the alginate/CaCO 3 evaluated in our previous report, , LM pectin/CaCO 3 undergoes sol–gel transition without adding acidic agents . Therefore, the effects of CO 2 could be observed by comparing the LM pectin/CaCO 3 hydrogels with and without the carbonated water (Figure b).…”

“…Several studies have used CO 2 to facilitate or trigger hydrogel fabrication based on pH changes, expecting that the CO 2 would be released from the hydrogel into the atmosphere. − Some studies have reported that the formation of LM pectin/CaCO 3 hydrogels and alginate/CaCO 3 hydrogels − can be stimulated by employing high-pressure or supercritical CO 2 to dissolve a considerable amount of CO 2 in polymer-containing gelation mixtures. In these methods, the temperature and pressure of CO 2 are essential parameters to control the physicochemical properties of the final hydrogels.…”

Functional polymers for modeling the formation of biogenic calcium carbonate and the design of new materials

“…Composite organo‐inorganic materials are widely used in a variety of applications, including construction materials, 1,2 biomedicine 3 including regenerative medicine, 4–7 drug delivery, 8–10 and so on. The skeletons of living organisms (bones in the vertebrate skeleton, teeth and horns, diatom algae frustules, mollusk shells, sea urchin needles and sponge spicules) also consist of composites.…”

Controlled polymerization of metal complex monomers – fabricating random copolymers comprising different metal species and nano-colloids

“…[1][2][3][4] Polymers with metal complexes on side chains are very promising as high-performance hybrid materials because they enable in-solution locally concentrated states of the metal complexes to remain as secondary valence sites, with better catalytic activity and molecular recognition. [5][6][7][8] Because the electron density-dependent properties of metal complexes are affected by their molecular neighborhood, grafting polymer complexes with different metal species can further widen the scope of polymer applications. 9,10 In general, the incorporation of metal complexes into the side chains is accomplished by mixing metal species with ligand-structured polymers (Scheme 1a).…”