Compact poly-electrolyte complex hydrogels of gelatin and sodium alginate for sensing wound status

This work reports a facile, cost-effective and green strategy to develop pH sensitive complex coacervate hydrogel for sensing wound status. Gallic acid, the active sensory ingredient, induces the formation of the polyelectrolyte complex between ampholytic gelatin and anionic sodium alginate. This makes the hydrogel unique with a good mechanical integrity, having a gel strength of 453 +/- 24 N, and a rupture force of 926 +/- 36 N. The visual color change of the hydrogel confirms its alkaline nature, while the intact color indicates an acidic environment and makes it incredibly user-friendly. The antioxidant property and biocompatibility of the developed hydrogel augment its utility as a biosensor.