Precise tetrafunctional streptavidin bioconjugates towards multifaceted drug delivery systems

The preparation of precise macromolecules with multiple functionalities remains a challenge in drug delivery. Here, a method to prepare stoichiometrically precise tetrafunctional streptavidin conjugates is presented with an exemplary structure combining exactly one fluorescent label, one cell targeting group, one nucleus penetrating peptide and one drug molecule.