Nu-Gel Hydrogel with alginate. Action The NU-GEL hydrogel is a transparent hydroactive amorphous gel containing sodium alginate. The hydrogel creates a moist wound healing environment that facilitates the natural autolytic debridement of the wound, and the addition of alginate enhances its absorption properties. The gel, by facilitating the hydration of the wound, can also be used to soften and moisturize the scab.