Forget Stitches. Your Skin's "Repair Manual" Was Outdated. Scientists Just Uploaded a New One. New Hydrogel Heals 90% of Wounds in 4 Hours — No Stitches Needed. Scientists have just unveiled what might be the closest thing to science-fiction healing made real: a super skin hydrogel that can close 90% of wounds in just four hours—and fully repair them within a single day.