Cell-Penetrating Peptides

Cell-penetrating peptides may cross the plasma membrane directly, enter through endocytosis, or use both routes. The apparent mechanism depends on the peptide, cargo, concentration, cell system, and assay.

A cell-penetrating peptide may enter cultured cells efficiently yet fail to deliver its cargo selectively to a target tissue in vivo. This guide explains the biological distinction and the evidence needed to evaluate selectivity.

A methods-focused guide to separating plasma-membrane binding, true CPP internalization, endosomal retention, and cytosolic delivery.