Efficient Intracellular Delivery of an MR Imaging Probe by a Novel Cell Penetrating Peptide

Introduction The quality of an intracellular targeted imaging probe or drug depends not only on the efficient delivery across the cell membrane but also on co-localization with its intracellular targets. In recent years, cell penetrating peptides (CPPs) have been investigated for their use as delivery tools. However, several studies reported on the entrapment of CPP conjugates into endosomes after uptake, thus, restricting their use for cytosolic targeting. Here, we are presenting the development of a novel cysteine rich CPP (derived from polypeptide crotamine (1)) able to distribute imaging probes into the entire cytosol.