A breakthrough in insulin delivery could one day spell an end to the invasive needles on which many people with diabetes rely. Using mice, minipigs, and lab-grown human skin samples, scientists have demonstrated a topical insulin treatment – an achievement long assumed impossible due to the large size of insulin molecules and their strong attraction to water, which prevents them from slipping through the skin's oily outer layers. "The skin-permeable polymer may enable non-invasive transdermal