Development of a new enzyme-responsive self-immolative spacer conjugate applicable to the controlled drug release

A new self-immolative spacer conjugate based on a chemical adaptor unit aiming at controlled releasing drugs was designed and synthesized. It releases a fluorophore which was used as a model drug via a spontaneous cyclization mechanism after cleavage of an enzyme substrate. This system was proved to be stable under physiological conditions and only decomposed triggered by enzyme. It provides a generic linkage allowing connection of a variety of drugs and targeted devices to the chemical adaptor.