Physical hydrogels of natural polysaccharides are considered
as
ideal candidates for wound dressing due to their natural biological
activity and no harmful cross-linking agents. However, it remains
a challenge to fabricate such hydrogel dressings in a facile and low-cost
way. Herein, we reported an easy and cost-effective method to construct
CO2-mediated alkali-neutralization Curdlan (CR) hydrogels
without using an external cross-linking agent. Two types of hydrogels
(denoted as CR-NaOH and CR-Na3PO4, respectively)
were fabricated by dissolving CR powders in a NaOH or Na3PO4 aqueous solution, followed by keeping the CR alkaline
solutions in air. The obtained pure CR hydrogels possessed a tunable
porous structure with walls containing different forms of nanofibrils.
These hydrogels exhibited much higher gel strength by comparison with
the gels prepared by conventional heating treatment. They were flexible,
stretchable, twistable, and conformable to arbitrarily curved skins.
Moreover, they exhibited ideal swellability, proper degradability,
and water vapor transmission rate, and their physicochemical properties
were closely related to CR concentration in the alkaline solution.
These two hydrogels also supported the growth of L929 cells. Importantly,
studies on wound healing revealed that both 3CR-NaOH and 3CR-Na3PO4 hydrogels were capable of accelerating the
wound healing process through recruiting more macrophages/fibroblasts,
inducing more collagen deposition and neovascularization (α-SMA
and CD31) without carrying any exogenous bioactive components. In
conclusion, the present work not only reported promising materials
for application in wound therapy but also offered a facile and safe
manufacturing procedure for generating pure CR physical hydrogels
with better performance.