The use of cell-penetrating peptides for drug delivery

In the past decade, several peptides that can translocate cell membranes have been identified. Some of these peptides, which can be divided into different families, have short amino acid sequences (10-27 residues in length) and enter the cell by a receptor-independent mechanism. Furthermore, these peptides are capable of internalizing hydrophilic cargoes. Although the detailed mechanism by which these molecules enter cells is poorly understood, their ability to traverse the membrane into the cytoplasm has provided a new and powerful biological tool for transporting drugs across cell membranes.