Ruthenium polypyridyl peptide conjugates: membrane permeable probes for cellular imaging

Abstract

Two novel polyarginine labelled ruthenium polypyridyl dyes are reported, one conjugated to five, (Ru–Ahx–R₅), and one to eight arginine residues, (Ru–Ahx–R₈); both complexes exhibit long-lived, intense, and oxygen-sensitive luminescence; (Ru–R₈) is passively, efficiently and very rapidly transported across the cell membrane into the cytoplasm without requirement for its permeablisation.