The world of cell penetrating: the future of medical applications.

Cell-penetrating peptides present huge biomedical applications in a variety of pathologies, thanks to their ability to penetrate membranes and carry a variety of cargoes inside cells. Progress in peptide synthesis has produced a greater availability of virtually any synthetic peptide, increasing their attractiveness. Most molecules when associated to a cell-penetrating peptides can be delivered into a cell, however, understanding of the critical factors influencing the uptake mechanism is of paramount importance to construct nanoplatforms for effective delivery and in medical applications. Focus is now on the state-of-art of the mechanisms enabling therapeutics/diagnostics to reach the site target of their activities, and in support of scientists developing platforms for drug delivery and personalized therapies.