Regioselective fluorescent labeling of N,N,N-trimethyl chitosan via oxime formation

► Selective fluorescent end-labeling of N,N,N-trimethyl chitosan via oxime formation. ► Molecular weight of ∼7.7 kDa for the fluorescently end-labeled N,N,N-trimethyl chitosan confirmed with NMR, fluorospectrometry and MALDI-TOF. ► Membrane bound and intracellular localization of the fluorescently end-labeled N,N,N-trimethyl chitosan in epithelial cells.