NOTICE:This is the peer-reviewed version of the following article:Juan M. Priegue, Daniel N. Crisan, José Martínez-Costas, Juan R. Granja, Francisco Fernandez-Trillo, and Javier Montenegro (2016),“In situ Functionalized Polymers for siRNA Delivery ; Angew. Chem. Int. Ed., 55, 7492–7495 [doi: 10.1002/anie.201601441]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archivingA new method is reported herein for screening the biological activity of functional polymers across a consistent degree of polymerization and in situ, that is, under aqueous conditions and without purification/isolation of candidate polymers. In brief, the chemical functionality of a poly(acryloyl hydrazide) scaff...