The invention relates to a modular transport platform (MTP) configured to penetrate a target cell, deliver the MTP into the target cell, provide a pH dependent membrane disruption activity, direct intracellular transport into a target subcellular compartment of the target cell, and couple the active agent within the modular platform. The modular transport platform includes: (1) a ligand module to target a specific receptor on the surface of the target cell; (2) an endosomolytic module that provides pH-dependent membrane disruption activity within the target cell; (3) an intracellular transport module to cause delivery of the MTP to a particular subcellular compartment; (4) a module for intracellular retention; (5) a module for subcellular recognition; (6) a substance to be transported by the MTP; and (7) a carrier module for unifying the modules and coupling the modules with the transported substance.