Each year, tens of thousands of people with diabetes in the U.S. have a lower limb amputated because a foot wound failed to heal. Identification of an enzyme that interferes with healing in diabetes patients may help prevent these amputations. Mayland Chang of the University of Notre Dame and colleagues looked for matrix metalloproteinases (MMPs) in the wounds of healthy and diabetic mice. The enzymes remodel the extracellular matrix in tissue during wound healing. The scientists used micrometer-sized polymer beads decorated with an inhibitor to snag active enzymes in the wounds. They detected active MMP-9 in both normal and diabetic tissue but found that levels of MMP-9 were almost two times as high in diabetic wounds as in normal ones, suggesting that MMP-9 is a roadblock to swift healing (ACS Chem. Biol. 2013, DOI: 10.1021/cb4005468). They treated wounds in diabetic mice with an inhibitor of MMP-9 and found that the wounds were 92% healed after 14 days, compared with 74% wound closure in untreated mice. The finding suggests that enzyme inhibition could be a wound treatment strategy.