FAP and neoplasm: IRDye800CW has a polyanionic structure and, althoughwidely used in clinical trials, suffers from nonspecific invivo binding, which prevents the maximization of fluorescenceintensity at the target site.17 FNIRTaghas a zwitterionic structure, which may improve its tumor-to-backgroundratio.18 On these premises, this work aimsto synthesize, validate, and compare, both in vitro and in vivo, two novel FAP-targeting fluorescentprobes for NIRF imaging applications.