Recent advances in cell-penetrating, non-peptide molecular carriers.

The intracellular delivery of proteins and other bioactive molecules by employing membrane-permeable carrier peptide vectors, e.g. HIV-1 Tat, Antp-HD, and related arginine-rich peptides are well known for a number of years. Because of some real and potential problems associated with these peptide carriers, such as instability due to various endogenous peptidases, uncertain in vivo delivery efficiency, potential neurotoxicity and immunogenicity, an urgent need exists for the development of efficient, non-peptide molecular carriers. This review briefly summarizes the structural characteristics and the delivery properties of the newly developed non-peptide carriers, in particular the ones developed in the author's laboratory, together with their potential as delivery vectors for poorly bioavailable drugs including small molecules, proteins, and nucleotides.