MMP9 and diabetes mellitus: CNPs, coatedwith GMs, might be able to react with matrix metalloproteinase 9 (MMP-9),which is often overexpressed and persists at the site of non-healingskin lesions in diabetes.199 As a result,the skin recovery process demands an equilibrium between the collagenbreakdown and the production of new components of the extracellularmatrix,200 as determined by substrate MMPand tissue metalloproteinase inhibitors.187