Design of a 1,8-naphthalimide-based OFF-ON type bioorthogonal reagent for fluorescent imaging in live cells

摘要

A novel 1,8-naphthalimide-based OFF-ON type fluorogenic sydnone(Naph-Syd) is designed as bioorthogonal probe for imaging.Sydnone moiety efficiently quenches the native fluorescence of 1,8-naphthalimide,which can be restored with the enhancement of about 300-fold,after reacting with strained cyclooctynes to form pyrazole products(Naph-Pyr).The second-order rate constant of this bioorthogonal cycloaddition can be up to 2.5 L mol^-1s^-1,which benefits imaging of biomolecules at low concentrations in cellular environment.