Cellular uptake of an α-AApeptide

Some short and cationic peptides such as the Tat peptide can cross the cell membrane and function as vectors for intracellular delivery. Here we show that an alpha-AApeptide is able to penetrate the membranes of living cells from an extracellular environment and enter the endosome and cytoplasm of cells. The efficiency of the cellular uptake is comparable to a Tat peptide (48-57) of the same length and is unexpectedly superior to an alpha-peptide with identical functional groups. The mechanism of uptake is similar to that of the Tat peptide and is through endocytosis by an energy-dependent pathway. Due to the easy synthesis of the alpha-AApeptides, their resistance to proteolytic hydrolysis, and their low cytotoxicity, alpha-AApeptides represent a new class of transporters for the delivery of drugs.