Fig. 1

Schematic representation of proposed mechanisms for cell-penetrating peptides (CPPs) internalization. The diagram illustrates that the involved pathways can be divided into two groups: direct penetration of plasma membrane (yellow) and endocytic pathways (purple). The fifirst type of process involves several energy independent models including membrane insertion of CPPs through pore formation and membrane destabilization through the carpet-like model or inverted micelle formation. Endocytic internalization of CPPs is an energy-dependent process that comprises macropinocytosis and endocytosis. Reprinted with permission from ref. [11] Copyright (2017) Elsevier